RDMA/core: Use refcount_t instead of atomic_t on refcount of ib_uverbs_device

The refcount_t API will WARN on underflow and overflow of a reference
counter, and avoid use-after-free risks.

Link: https://lore.kernel.org/r/1622194663-2383-8-git-send-email-liweihang@huawei.com
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/uverbs: Extend CQ to get its own asynchronous event FD

Extend CQ to get its own asynchronous event FD.
The event FD is an optional attribute, in case wasn't given the ufile
event FD will be used.

Link: https://lore.kernel.org/r/20200519072711.257271-4-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Refactor related objects to use their own asynchronous event FD

Refactor related objects to use their own asynchronous event FD.
The ufile event FD will be the default in case an object won't have its own
event FD.

Link: https://lore.kernel.org/r/20200519072711.257271-3-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Move IB_EVENT_DEVICE_FATAL to destroy_uobj

When multiple async FDs were allowed to exist the idea was for all
broadcast events to be delivered to all async FDs, however
IB_EVENT_DEVICE_FATAL was missed.

Instead of having ib_uverbs_free_hw_resources() special case the global
async_fd, have it cause the event during the uobject destruction. Every
async fd is now a uobject so simply generate the IB_EVENT_DEVICE_FATAL
while destroying the async fd uobject. This ensures every async FD gets a
copy of the event.

Fixes: d680e88e2013 ("RDMA/core: Add UVERBS_METHOD_ASYNC_EVENT_ALLOC")
Link: https://lore.kernel.org/r/20200507063348.98713-3-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Do not discard the IB_EVENT_DEVICE_FATAL event

The commit below moved all of the destruction to the disassociate step and
cleaned up the event channel during destroy_uobj.

However, when ib_uverbs_free_hw_resources() pushes IB_EVENT_DEVICE_FATAL
and then immediately goes to destroy all uobjects this causes
ib_uverbs_free_event_queue() to discard the queued event if userspace
hasn't already read() it.

Unlike all other event queues async FD needs to defer the
ib_uverbs_free_event_queue() until FD release. This still unregisters the
handler from the IB device during disassociation.

Fixes: 3e032c0e92aa ("RDMA/core: Make ib_uverbs_async_event_file into a uobject")
Link: https://lore.kernel.org/r/20200507063348.98713-2-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Make the entire API tree static

Compilation of mlx5 driver without CONFIG_INFINIBAND_USER_ACCESS generates
the following error.

on x86_64:

ld: drivers/infiniband/hw/mlx5/main.o: in function `mlx5_ib_handler_MLX5_IB_METHOD_VAR_OBJ_ALLOC':
main.c:(.text+0x186d): undefined reference to `ib_uverbs_get_ucontext_file'
ld: drivers/infiniband/hw/mlx5/main.o:(.rodata+0x2480): undefined reference to `uverbs_idr_class'
ld: drivers/infiniband/hw/mlx5/main.o:(.rodata+0x24d8): undefined reference to `uverbs_destroy_def_handler'

This is happening because some parts of the UAPI description are not
static. This is a hold over from earlier code that relied on struct
pointers to refer to object types, now object types are referenced by
number. Remove the unused globals and add statics to the remaining UAPI
description elements.

Remove the redundent #ifdefs around mlx5_ib_*defs and obsolete
mlx5_ib_get_devx_tree().

The compiler now trims alot more unused code, including the above
problematic definitions when !CONFIG_INFINIBAND_USER_ACCESS.

Fixes: 7be76bef320b ("IB/mlx5: Introduce VAR object and its alloc/destroy methods")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Add ioctl command to get a device context

Allow future extensions of the get context command through the uverbs
ioctl kabi.

Unlike the uverbs version this does not return an async_fd as well, that
has to be done with another command.

Link: https://lore.kernel.org/r/1578506740-22188-5-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Use READ_ONCE for ib_ufile.async_file

The writer for async_file holds the ucontext_lock, while the readers are
left unlocked. Most readers rely on an implicit locking, either by having
a uobject (which cannot be created before a context) or by holding the
ib_ufile kref.

However ib_uverbs_free_hw_resources() has no implicit lock and has a
possible race. Make this all clear and sane by using READ_ONCE
consistently.

Link: https://lore.kernel.org/r/1578504126-9400-15-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Make ib_uverbs_async_event_file into a uobject

This makes async events aligned with completion events as both are full
uobjects of FD type and use the same uobject lifecycle.

A bunch of duplicate code is consolidated and the general flow between the
two FDs is now very similar.

Link: https://lore.kernel.org/r/1578504126-9400-14-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Simplify type usage for ib_uverbs_async_handler()

This function works on an ib_uverbs_async_file. Accept that as a parameter
instead of the struct ib_uverbs_file.

Consoldiate all the callers working from an ib_uevent_object to a single
function and locate the async_file directly from the struct ib_uobject
instead of using context_ptr.

Link: https://lore.kernel.org/r/1578504126-9400-11-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Make ib_ucq_object use ib_uevent_object

Any uobject that sends events into the async_event_file should be using
ib_uevent_object so it can use the standard uevent based helper
functions. CQ pushes events into both the async_event and the comp_channel
in an open coded way. Move the async events related stuff to
ib_uevent_object.

Link: https://lore.kernel.org/r/1578504126-9400-6-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Prevent potential underflow

The issue is in drivers/infiniband/core/uverbs_std_types_cq.c in the
UVERBS_HANDLER(UVERBS_METHOD_CQ_CREATE) function. We check that:

if (attr.comp_vector >= attrs->ufile->device->num_comp_vectors) {

But we don't check if "attr.comp_vector" is negative. It could
potentially lead to an array underflow. My concern would be where
cq->vector is used in the create_cq() function from the cxgb4 driver.

And really "attr.comp_vector" is appears as a u32 to user space so that's
the right type to use.

Fixes: 9ee79fce3642 ("IB/core: Add completion queue (cq) object actions")
Link: https://lore.kernel.org/r/20191011133419.GA22905@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

uverbs: Convert idr to XArray

The word 'idr' is scattered throughout the API, so I haven't changed it,
but the 'idr' variable is now an XArray.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/ucontext: Fix regression with disassociate

When this code was consolidated the intention was that the VMA would
become backed by anonymous zero pages after the zap_vma_pte - however this
very subtly relied on setting the vm_ops = NULL and clearing the VM_SHARED
bits to transform the VMA into an anonymous VMA. Since the vm_ops was
removed this broke.

Now userspace gets a SIGBUS if it touches the vma after disassociation.

Instead of converting the VMA to anonymous provide a fault handler that
puts a zero'd page into the VMA when user-space touches it after
disassociation.

Cc: stable@vger.kernel.org
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Fixes: 5f9794dc94f5 ("RDMA/ucontext: Add a core API for mmaping driver IO memory")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB: Remove 'uobject->context' dependency in object destroy APIs

Now that we have the udata passed to all the ib_xxx object destroy APIs
and the additional macro 'rdma_udata_to_drv_context' to get the
ib_ucontext from ib_udata stored in uverbs_attr_bundle, we can finally
start to remove the dependency of the drivers in the
ib_xxx->uobject->context.

Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB: Pass uverbs_attr_bundle down ib_x destroy path

The uverbs_attr_bundle with the ucontext is sent down to the drivers ib_x
destroy path as ib_udata. The next patch will use the ib_udata to free the
drivers destroy path from the dependency in 'uobject->context' as we
already did for the create path.

Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/core: Move query port to ioctl

Add a method for query port under the uverbs global methods. Current
ib_port_attr struct is passed as a single attribute and port_cap_flags2 is
added as a new attribute to the function.

Signed-off-by: Michael Guralnik <michaelgur@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Implement an ioctl that can call write and write_ex handlers

Now that the handlers do not process their own udata we can make a
sensible ioctl that wrappers them. The ioctl follows the same format as
the write_ex() and has the user explicitly specify the core and driver
in/out opaque structures and a command number.

This works for all forms of write commands.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

RDMA/uverbs: Make all the method functions in uverbs_cmd static

Now that we use struct uverbs_uapi to link the method functions to the
dispatcher there is no reason to have them be extern symbols.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

RDMA/uverbs: Convert the write interface to use uverbs_api

This organizes the write commands into objects and links them to the
uverbs_api data structure. The command path is reworked to use uapi
instead of its internal structures.

The command mask is moved from a runtime check to a registration time
check in the uapi.

Since the write interface does not have the object ID as part of the
command, the radix bins are converted into linear lists to support the
lookup.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

RDMA/ucontext: Add a core API for mmaping driver IO memory

To support disassociation and PCI hot unplug, we have to track all the
VMAs that refer to the device IO memory. When disassociation occurs the
VMAs have to be revised to point to the zero page, not the IO memory, to
allow the physical HW to be unplugged.

The three drivers supporting this implemented three different versions
of this algorithm, all leaving something to be desired. This new common
implementation has a few differences from the driver versions:

- Track all VMAs, including splitting/truncating/etc. Tie the lifetime of
the private data allocation to the lifetime of the vma. This avoids any
tricks with setting vm_ops which Linus didn't like. (see link)
- Support multiple mms, and support properly tracking mmaps triggered by
processes other than the one first opening the uverbs fd. This makes
fork behavior of disassociation enabled drivers the same as fork support
in normal drivers.
- Don't use crazy get_task stuff.
- Simplify the approach for to racing between vm_ops close and
disassociation, fixing the related bugs most of the driver
implementations had. Since we are in core code the tracking list can be
placed in struct ib_uverbs_ufile, which has a lifetime strictly longer
than any VMAs created by mmap on the uverbs FD.

Link: https://www.spinics.net/lists/stable/msg248747.html
Link: https://lkml.kernel.org/r/CA+55aFxJTV_g46AQPoPXen-UPiqR1HGMZictt7VpC-SMFbm3Cw@mail.gmail.com
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

RDMA/uverbs: Remove is_closed from ib_uverbs_file

This does nothing but indicate if the uverbs_file is in the device's list,
use list_del_init instead.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

RDMA/uverbs: Move flow resources initialization

Use ib_set_flow() when initializing flow related resources.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Use device.groups to initialize device attributes

Instead of explicitly adding device attribute files and handling such
error conditions, depend on device core layer to create device attributes
files based group pointer NULL terminated array.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/uverbs: Use cdev_device_add() instead of cdev_add()

Instead of doing two step process to add char device and create underlying
device, use cdev_device_add() which does both.

Currently a kobject per uverbs_device is created to keep reference to its
holding ib_uverbs_device in addition to its underlying device 'dev'.

Instead just use uverbs_device->dev to keep a reference to.

With this change there is single reference tracker for ib_uverbs_device
structure.

This allows for subsequent patch to registers group attribute as well
using single API cdev_device_add().

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Remove struct uverbs_root_spec and all supporting code

Everything now uses the uverbs_uapi data structure.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Build the specs into a radix tree at runtime

This radix tree datastructure is intended to replace the 'hash' structure
used today for parsing ioctl methods during system calls. This first
commit introduces the structure and builds it from the existing .rodata
descriptions.

The so-called hash arrangement is actually a 5 level open coded radix tree.
This new version uses a 3 level radix tree built using the radix tree
library.

Overall this is much less code and much easier to build as the radix tree
API allows for dynamic modification during the building. There is a small
memory penalty to pay for this, but since the radix tree is allocated on
a per device basis, a few kb of RAM seems immaterial considering the
gained simplicity.

The radix tree is similar to the existing tree, but also has a 'attr_bkey'
concept, which is a small value'd index for each method attribute. This is
used to simplify and improve performance of everything in the next
patches.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>

IB/uverbs: Do not block disassociate during write()

Now that all the callbacks are safe to run concurrently with
disassociation this test can be eliminated. The ufile core infrastructure
becomes entirely self contained and is not sensitive to disassociation.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Do not pass struct ib_device to the write based methods

This is a step to get rid of the global check for disassociation. In this
model, the ib_dev is not proven to be valid by the core code and cannot be
provided to the method. Instead, every method decides if it is able to
run after disassociation and obtains the ib_dev using one of three
different approaches:

- Call srcu_dereference on the udevice's ib_dev. As before, this means
the method cannot be called after disassociation begins.
(eg alloc ucontext)
- Retrieve the ib_dev from the ucontext, via ib_uverbs_get_ucontext()
- Retrieve the ib_dev from the uobject->object after checking
under SRCU if disassociation has started (eg uobj_get)

Largely, the code is all ready for this, the main work is to provide a
ib_dev after calling uobj_alloc(). The few other places simply use
ib_uverbs_get_ucontext() to get the ib_dev.

This flexibility will let the next patches allow destroy to operate
after disassociation.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Fix locking around struct ib_uverbs_file ucontext

We have a parallel unlocked reader and writer with ib_uverbs_get_context()
vs everything else, and nothing guarantees this works properly.

Audit and fix all of the places that access ucontext to use one of the
following locking schemes:
- Call ib_uverbs_get_ucontext() under SRCU and check for failure
- Access the ucontext through an struct ib_uobject context member
while holding a READ or WRITE lock on the uobject.
This value cannot be NULL and has no race.
- Hold the ucontext_lock and check for ufile->ucontext !NULL

This also re-implements ib_uverbs_get_ucontext() in a way that is safe
against concurrent ib_uverbs_get_context() and disassociation.

As a side effect, every access to ucontext in the commands is via
ib_uverbs_get_context() with an error check, or via the uobject, so there
is no longer any need for the core code to check ucontext on every command
call. These checks are also removed.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Rework the locking for cleaning up the ucontext

The locking here has always been a bit crazy and spread out, upon some
careful analysis we can simplify things.

Create a single function uverbs_destroy_ufile_hw() that internally handles
all locking. This pulls together pieces of this process that were
sprinkled all over the places into one place, and covers them with one
lock.

This eliminates several duplicate/confusing locks and makes the control
flow in ib_uverbs_close() and ib_uverbs_free_hw_resources() extremely
simple.

Unfortunately we have to keep an extra mutex, ucontext_lock. This lock is
logically part of the rwsem and provides the 'down write, fail if write
locked, wait if read locked' semantic we require.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Revise and clarify the rwsem and uobjects_lock

Rename 'cleanup_rwsem' to 'hw_destroy_rwsem' which is held across any call
to the type destroy function (aka 'hw' destroy). The main purpose of this
lock is to prevent normal add and destroy from running concurrently with
uverbs_cleanup_ufile()

Since the uobjects list is always manipulated under the 'hw_destroy_rwsem'
we can eliminate the uobjects_lock in the cleanup function. This allows
converting that lock to a very simple spinlock with a narrow critical
section.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB: Enable uverbs_destroy_def_handler to be used by drivers

Enable uverbs_destroy_def_handler to be used by drivers and replace
current code to use it.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Replace ib_ucq_object uverbs_file with the one in ib_uobject

Now that ib_uobject has a ib_uverbs_file we don't need this extra one in
ib_ucq_object.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Remove ib_uobject_file

The only purpose for this structure was to hold the ib_uobject_file
pointer, but now that is part of the standard ib_uobject the structure
no longer makes any sense, so get rid of it.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

IB/uverbs: Move non driver related elements from ib_ucontext to ib_ufile

The IDR is part of the ib_ufile so all the machinery to lock it, handle
closing and disassociation rightly belongs to the ufile not the ucontext.

This changes the lifetime of that data to match the lifetime of the file
descriptor which is always strictly longer than the lifetime of the
ucontext.

We need the entire locking machinery to continue to exist after ucontext
destruction to allow us to return the destroy data after a device has been
disassociated.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

RDMA/uverbs: Simplify UVERBS_OBJECT and _TREE family of macros

Instead of the large set of indirecting macros, define the few needed
macros to directly instantiate the struct uverbs_oject_tree_def and
associated objects list.

This is small amount of code duplication but the readability is far
better.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

IB: Improve uverbs_cleanup_ucontext algorithm

Improve uverbs_cleanup_ucontext algorithm to work properly when the
topology graph of the objects cannot be determined at compile time. This
is the case with objects created via the devx interface in mlx5.

Typically uverbs objects must be created in a strict topologically sorted
order, so that LIFO ordering will generally cause them to be freed
properly. There are only a few cases (eg memory windows) where objects can
point to things out of the strict LIFO order.

Instead of using an explicit ordering scheme where the HW destroy is not
allowed to fail, go over the list multiple times and allow the destroy
function to fail. If progress halts then a final, desperate, cleanup is
done before leaking the memory. This indicates a driver bug.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Add support for flow counters

The struct ib_uverbs_flow_spec_action_count associates a counters object
with the flow.

Post this association the flow counters can be read via the counters
object.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Raed Salem <raeds@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Add create/destroy counters support

User space application which uses counters functionality, is expected to
allocate/release the counters resources by calling create/destroy verbs
and in turn get a unique handle that can be used to attach the counters to
its counted type.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Raed Salem <raeds@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Add alloc/free dm uverbs ioctl support

This change adds uverbs support for allocation/freeing
of device memory commands.

A new uverbs object is defined of type idr to represent
and track the new resource type allocation per context.

The API requires provider driver to implement 2 new ib_device
callbacks - one for allocation and one for deallocation which
return and accept (respectively) the ib_dm object which represents
the allocated memory on the device.

The support is added via the ioctl command infrastructure
only.

Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Introduce ESP steering match filter

Adding a new ESP steering match filter that could match against
spi and seq used in IPSec protocol.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Add action_handle flow steering specification

Binding a flow_action to flow steering rule requires using a new
specification. Therefore, adding such an IB_FLOW_SPEC_ACTION_HANDLE flow
specification.

Flow steering rules could use flow_action(s) and as of that we need to
avoid deleting flow_action(s) as long as they're being used.
Moreover, when the attached rules are deleted, action_handle reference
count should be decremented. Introducing a new mechanism of flow
resources to keep track on the attached action_handle(s). Later on, this
mechanism should be extended to other attached flow steering resources
like flow counters.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Add flow_action create and destroy verbs

A verbs application may receive and transmits packets using a data
path pipeline. Sometimes, the first stage in the receive pipeline or
the last stage in the transmit pipeline involves transforming a
packet, either in order to make it easier for later stages to process
it or to prepare it for transmission over the wire. Such transformation
could be stripping/encapsulating the packet (i.e. vxlan),
decrypting/encrypting it (i.e. ipsec), altering headers, doing some
complex FPGA changes, etc.

Some hardware could do such transformations without software data path
intervention at all. The flow steering API supports steering a
packet (either to a QP or dropping it) and some simple packet
immutable actions (i.e. tagging a packet). Complex actions, that may
change the packet, could bloat the flow steering API extensively.
Sometimes the same action should be applied to several flows.
In this case, it's easier to bind several flows to the same action and
modify it than change all matching flows.

Introducing a new flow_action object that abstracts any packet
transformation (out of a standard and well defined set of actions).
This flow_action object could be tied to a flow steering rule via a
new specification.

Currently, we support esp flow_action, which encrypts or decrypts a
packet according to the given parameters. However, we present a
flexible schema that could be used to other transformation actions tied
to flow rules.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Refactor kern_spec_to_ib_spec_filter

The current implementation of kern_spec_to_ib_spec_filter, which takes
a uAPI based flow steering specification and creates the respective kernel
API flow steering structure, gets a ib_uverbs_flow_spec structure.
The new flow_action uAPI gets a match mask and filter from user-space
which aren't encoded in the flow steering's ib_uverbs_flow_spec structure.
Exporting the logic out of kern_spec_to_ib_spec_filter to get user-space
blobs rather than ib_uverbs_flow_spec structure.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Move ioctl path of create_cq and destroy_cq to a new file

Currently, all objects are declared in uverbs_std_types. This could lead
to a huge file once we implement all objects, methods and handlers.
Moving each object to its own file to keep the files smaller and more
readable. uverbs_std_types.c will only contain the parsing tree
definition and objects without any methods.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Expose parsing tree of all common objects to providers

The ioctl() based uverbs is based on merging feature trees. This teaches
the generic parser how to parse methods according to the provider's
support. In order to support merging with the common objects, exporting
the common-object-tree to the provider drivers.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Move to new headers and make naming consistent

Use macros to make names consistent in ioctl() uAPI:
The ioctl() uAPI works with object-method hierarchy. The method part
also states which handler should be executed when this method is called
from user-space. Therefore, we need to tie method, method's id, method's
handler and the object owning this method together.
Previously, this was done through explicit developer chosen names.
This makes grepping the code harder. Changing the method's name,
method's handler and object's name to be automatically generated based
on the ids.

The headers are split in a way so they be included and used by
user-space. One header strictly contains structures that are used
directly by user-space applications, where another header is used for
internal library (i.e. libibverbs) to form the ioctl() commands.
Other header simply contains the required general command structure.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Allow CQ moderation with modify CQ

Uverbs support in modify_cq for CQ moderation only.
Gives ability to change cq_max_count and cq_period.
CQ moderation enhance performance by moderating the number
of CQEs needed to create an event instead of application
having to suffer from event per-CQE.
To achieve CQ moderation the application needs to set cq_max_count
and cq_period.
cq_max_count - defines the number of CQEs needed to create an event.
cq_period - defines the timeout (micro seconds) between last
event and a new one that will occur even if
cq_max_count was not satisfied

Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: clean up INIT_UDATA() macro usage

After changing INIT_UDATA_BUF_OR_NULL() to an inline function,
this does the same change to INIT_UDATA for consistency.
I'm keeping it separate as this part is much larger and
we wouldn't want to backport this to stable kernels if we
ever want to address the gcc warnings by backporting the
first patch.

Again, using an inline function gives us better type
safety here among other issues with macros. I'm using
u64_to_user_ptr() to convert the user pointer to simplify
the logic rather than adding lots of new type casts.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: clean up INIT_UDATA_BUF_OR_NULL usage

We get a harmless warning about the fact that we use the result of a
multiplication as a condition:

drivers/infiniband/core/uverbs_main.c: In function 'ib_uverbs_write':
drivers/infiniband/core/uverbs_main.c:787:40: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
drivers/infiniband/core/uverbs_main.c:787:117: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
drivers/infiniband/core/uverbs_main.c:790:50: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
drivers/infiniband/core/uverbs_main.c:790:151: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]

This avoids the problem by using an inline function in place of
the macro.

Fixes: a96e4e2ffe43 ("IB/uverbs: New macro to set pointers to NULL if length is 0 in INIT_UDATA()")
Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://patchwork.kernel.org/patch/9940777/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Expose ioctl interface through experimental Kconfig

Add CONFIG_INFINIBAND_EXP_USER_ACCESS that enables the ioctl
interface. This interface is experimental and is subject to change.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Assign root to all drivers

In order to use the parsing tree, we need to assign the root
to all drivers. Currently, we just assign the default parsing
tree via ib_uverbs_add_one. The driver could override this by
assigning a parsing tree prior to registering the device.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Introduce drop flow specification

This flow steering specification identifies flow for drop by the HW.
If user create a flow only with the drop specification,
then all the packets that hit this flow will be dropped, otherwise the HW
will drop only the packets that match the other L2/L3/L4 specifications.

Signed-off-by: Slava Shwartsman <slavash@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Rename uverbs event file structure

Previously, ib_uverbs_event_file was suffixed by _file as it contained
the actual file information. Since it's now only used as base struct
for ib_uverbs_async_event_file and ib_uverbs_completion_event_file,
we change its name to ib_uverbs_event_queue. This represents its
logical role better.

Fixes: 1e7710f3f656 ('IB/core: Change completion channel to use the reworked objects schema')
Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Change completion channel to use the reworked objects schema

This patch adds the standard fd based type - completion_channel.
The completion_channel is now prefixed with ib_uobject, similarly
to the rest of the uobjects.
This requires a few changes:
(1) We define a new completion channel fd based object type.
(2) completion_event and async_event are now two different types.
This means they use different fops.
(3) We release the completion_channel exactly as we release other
idr based objects.
(4) Since ib_uobjects are already kref-ed, we only add the kref to the
async event.

A fd object requires filling out several parameters. Its op pointer
should point to uverbs_fd_ops and its size should be at least the
size if ib_uobject. We use a macro to make the type declaration
easier.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Add support for fd objects

The completion channel we use in verbs infrastructure is FD based.
Previously, we had a separate way to manage this object. Since we
strive for a single way to manage any kind of object in this
infrastructure, we conceptually treat all objects as subclasses
of ib_uobject.

This commit adds the necessary mechanism to support FD based objects
like their IDR counterparts. FD objects release need to be synchronized
with context release. We use the cleanup_mutex on the uverbs_file for
that.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Add lock to multicast handlers

When two handlers used the same object in the old schema, we blocked
the process in the kernel. The new schema just returns -EBUSY. This
could lead to different behaviour in applications between the old
schema and the new schema. In most cases, using such handlers
concurrently could lead to crashing the process. For example, if
thread A destroys a QP and thread B modifies it, we could have the
destruction happens before the modification. In this case, we are
accessing freed memory which could lead to crashing the process.
This is true for most cases. However, attaching and detaching
a multicast address from QP concurrently is safe. Therefore, we
preserve the original behaviour by adding a lock there.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Change idr objects to use the new schema

This changes only the handlers which deals with idr based objects to
use the new idr allocation, fetching and destruction schema.
This patch consists of the following changes:
(1) Allocation, fetching and destruction is done via idr ops.
(2) Context initializing and release is done through
uverbs_initialize_ucontext and uverbs_cleanup_ucontext.
(3) Ditching the live flag. Mostly, this is pretty straight
forward. The only place that is a bit trickier is in
ib_uverbs_open_qp. Commit [1] added code to check whether
the uobject is already live and initialized. This mostly
happens because of a race between open_qp and events.
We delayed assigning the uobject's pointer in order to
eliminate this race without using the live variable.

[1] commit a040f95dc819
("IB/core: Fix XRC race condition in ib_uverbs_open_qp")

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Add idr based standard types

This patch adds the standard idr based types. These types are
used in downstream patches in order to initialize, destroy and
lookup IB standard objects which are based on idr objects.

An idr object requires filling out several parameters. Its op pointer
should point to uverbs_idr_ops and its size should be at least the
size of ib_uobject. We add a macro to make the type declaration easier.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Refactor idr to be per uverbs_file

The current code creates an idr per type. Since types are currently
common for all drivers and known in advance, this was good enough.
However, the proposed ioctl based infrastructure allows each driver
to declare only some of the common types and declare its own specific
types.

Thus, we decided to implement idr to be per uverbs_file.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Add support for flow tag

The struct ib_uverbs_flow_spec_action_tag associates a tag_id with the
flow defined by any number of other flow_spec entries which can reference
L2, L3, and L4 packet contents.

Use of ib_uverbs_flow_spec_action_tag allows the consumer to identify
the set of rules which where matched by
the packet by examining the tag_id in the CQE.

Signed-off-by: Moses Reuben <mosesr@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Extend modify_qp and support packet pacing

An new uverbs command ib_uverbs_ex_modify_qp is added to support more QP
attributes. User driver should choose to call the legacy/extended API
based on input mask.

IB_USER_LAST_QP_ATTR_MASK is added to indicated the maximum bit position
which supports legacy ib_uverbs_modify_qp.
IB_USER_LEGACY_LAST_QP_ATTR_MASK indicates the maximum bit position
which supports ib_uverbs_ex_modify_qp, the value of this mask should be
updated if new mask is added later.

Along with this change, rate_limit is supported by the extended command,
user driver could use it to control packet packing.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Fix race between uverbs_close and remove_one

Fixes an oops that might happen if uverbs_close races with
remove_one.

Both contexts may run ib_uverbs_cleanup_ucontext, it depends
on the flow.

Currently, there is no protection for a case that remove_one
didn't make the cleanup it runs to its end, the underlying
ib_device was freed then uverbs_close will call
ib_uverbs_cleanup_ucontext and OOPs.

Above might happen if uverbs_close deleted the file from the list
then remove_one didn't find it and runs to its end.

Fixes to protect against that case by a new cleanup lock so that
ib_uverbs_cleanup_ucontext will be called always before that
remove_one is ended.

Fixes: 35d4a0b63dc0 ("IB/uverbs: Fix race between ib_uverbs_open and remove_one")
Reported-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Add IPv6 support to flow steering

Add IPv6 flow specification support.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Introduce RWQ Indirection table

User applications that want to spread traffic on several WQs, need to
create an indirection table, by using already created WQs.

Adding uverbs API in order to create and destroy this table.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Add WQ support

User space applications which use RSS functionality need to create
a work queue object (WQ). The lifetime of such an object is:
* Create a WQ
* Modify the WQ from reset to init state.
* Use the WQ (by downstream patches).
* Destroy the WQ.

These commands are added to the uverbs API.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@rimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB: remove in-kernel support for memory windows

Remove the unused ib_allow_mw and ib_bind_mw functions, remove the
unused IB_WR_BIND_MW and IB_WC_BIND_MW opcodes and move ib_dealloc_mw
into the uverbs module.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> [core]
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Extend ib_uverbs_create_qp

ib_uverbs_ex_create_qp follows the extension verbs
mechanism. New features (for example, QP creation flags
field which is added in a downstream patch) could used
via user-space libraries without breaking the ABI.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Enable device removal when there are active user space applications

Enables the uverbs_remove_one to succeed despite the fact that there are
running IB applications working with the given ib device. This
functionality enables a HW device to be unbind/reset despite the fact that
there are running user space applications using it.

It exposes a new IB kernel API named 'disassociate_ucontext' which lets
a driver detaching its HW resources from a given user context without
crashing/terminating the application. In case a driver implemented the
above API and registered with ib_uverb there will be no dependency between its
device to its uverbs_device. Upon calling remove_one of ib_uverbs the call
should return after disassociating the open HW resources without waiting to
clients disconnecting. In case driver didn't implement this API there will be no
change to current behaviour and uverbs_remove_one will return only when last
client has disconnected and reference count on uverbs device became 0.

In case the lower driver device was removed any application will
continue working over some zombie HCA, further calls will ended with an
immediate error.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Explicitly pass ib_dev to uverbs commands

Done in preparation for deploying RCU for the device removal
flow. Allows isolating the RCU handling to the uverb_main layer and
keeping the uverbs_cmd code as is.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Fix race between ib_uverbs_open and remove_one

Fixes: 2a72f212263701b927559f6850446421d5906c41 ("IB/uverbs: Remove dev_table")

Before this commit there was a device look-up table that was protected
by a spin_lock used by ib_uverbs_open and by ib_uverbs_remove_one. When
it was dropped and container_of was used instead, it enabled the race
with remove_one as dev might be freed just after:
dev = container_of(inode->i_cdev, struct ib_uverbs_device, cdev) but
before the kref_get.

In addition, this buggy patch added some dead code as
container_of(x,y,z) can never be NULL and so dev can never be NULL.
As a result the comment above ib_uverbs_open saying "the open method
will either immediately run -ENXIO" is wrong as it can never happen.

The solution follows Jason Gunthorpe suggestion from below URL:
https://www.mail-archive.com/linux-rdma@vger.kernel.org/msg25692.html

cdev will hold a kref on the parent (the containing structure,
ib_uverbs_device) and only when that kref is released it is
guaranteed that open will never be called again.

In addition, fixes the active count scheme to use an atomic
not a kref to prevent WARN_ON as pointed by above comment
from Jason.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/uverbs: Fix reference counting usage of event files

Fix the reference counting usage to be handled in the event file
creation/destruction function, instead of being done by the caller.
This is done for both async/non-async event files.

Based on Jason Gunthorpe report at https://www.mail-archive.com/
linux-rdma@vger.kernel.org/msg24680.html:
"The existing code for this is broken, in ib_uverbs_get_context all
the error paths between ib_uverbs_alloc_event_file and the
kref_get(file->ref) are wrong - this will result in fput() which will
call ib_uverbs_event_close, which will try to do kref_put and
ib_unregister_event_handler - which are no longer paired."

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Extend ib_uverbs_create_cq

ib_uverbs_ex_create_cq follows the extension verbs
mechanism. New features (for example, CQ creation flags
field which is added in a downstream patch) could used
via user-space libraries without breaking the ABI.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/core: Add support for extended query device caps

Add extensible query device capabilities verb to allow adding new features.
ib_uverbs_ex_query_device is added and copy_query_dev_fields is used to copy
capability fields to be used by both ib_uverbs_query_device and
ib_uverbs_ex_query_device.

Following the discussion about this patch [1], the code now validates
the command's comp_mask is zero, returning -EINVAL for unknown values,
in order to allow extending the verb in the future.

The verb also checks the user-space provided response buffer size and
only fills in capabilities that will fit in the buffer. In attempt to
follow the spirit of presentation [2] by Tzahi Oved that was presented
during OpenFabrics Alliance International Developer Workshop 2013, the
comp_mask bits will only describe which fields are valid. Furthermore,
fields that can simply be cleared when they are not supported, do not
require a comp_mask bit at all. The verb returns a response_length
field containing the actual number of bytes written by the kernel, so
that a newer version running on an older kernel can tell which fields
were actually returned.

[1] [PATCH v1 0/5] IB/core: extended query device caps cleanup for v3.19
http://thread.gmane.org/gmane.linux.kernel.api/7889/

[2] https://www.openfabrics.org/images/docs/2013_Dev_Workshop/Tues_0423/2013_Workshop_Tues_0830_Tzahi_Oved-verbs_extensions_ofa_2013-tzahio.pdf

Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Reviewed-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

Revert "IB/core: Add support for extended query device caps"

While commit 7e36ef8205ff ("IB/core: Temporarily disable
ex_query_device uverb") is correct as it makes the extended
QUERY_DEVICE uverb (which came as part of commit 5a77abf9a97a
("IB/core: Add support for extended query device caps") and commit
860f10a799c8 ("IB/core: Add flags for on demand paging support")) not
available to userspace, it doesn't address the initial issue regarding
ib_copy_to_udata() [1][2].

Additionally, further discussions around this new uverb seems to
conclude it would require a different data structure than the one
currently described in <rdma/ib_user_verbs.h> [3].

Both of these issues require a revert of the changes, so this patch
partially reverts commit 8cdd312cfed7 ("IB/mlx5: Implement the ODP
capability query verb") and commit 860f10a799c8 ("IB/core: Add flags
for on demand paging support") and fully reverts commit 5a77abf9a97a
("IB/core: Add support for extended query device caps").

[1] "Re: [PATCH v3 06/17] IB/core: Add support for extended query device caps"
http://mid.gmane.org/1418733236.2779.26.camel@opteya.com

[2] "Re: [PATCH] IB/core: Temporarily disable ex_query_device uverb"
http://mid.gmane.org/1423067503.3030.83.camel@opteya.com

[3] "RE: [PATCH v1 1/5] IB/uverbs: ex_query_device: answer must not depend on request's comp_mask"
http://mid.gmane.org/2807E5FD2F6FDA4886F6618EAC48510E0CC12C30@CRSMSX101.amr.corp.intel.com

Cc: Eli Cohen <eli@mellanox.com>
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Add support for extended query device caps

Add extensible query device capabilities verb to allow adding new features.
ib_uverbs_ex_query_device is added and copy_query_dev_fields is used to
copy capability fields to be used by both ib_uverbs_query_device and
ib_uverbs_ex_query_device.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Add user MR re-registration support

Memory re-registration is a feature that enables changing the
attributes of a memory region registered by user-space, including PD,
translation (address and length) and access flags.

Add the required support in uverbs and the kernel verbs API.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/uverbs: New macro to set pointers to NULL if length is 0 in INIT_UDATA()

Trying to have a ternary operator to choose between NULL (or 0) and the
real pointer value in invocations leads to an impossible choice between
a sparse error about a literal 0 used as a NULL pointer, and a gcc
warning about "pointer/integer type mismatch in conditional expression."

Rather than clutter the source with more casts, move the ternary
operator into a new INIT_UDATA_BUF_OR_NULL() macro, which makes it
easier to use and simplifies its callers.

Reported-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: const'ify inbuf in struct ib_udata

Userspace input buffer is not modified by kernel, so it can be 'const'.

This is also a prerequisite to remove the implicit cast
from INIT_UDATA().

Link: http://marc.info/?i=cover.1386798254.git.ydroneaud@opteya.com>
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Re-enable create_flow/destroy_flow uverbs

This commit reverts commit 7afbddfae993 ("IB/core: Temporarily disable
create_flow/destroy_flow uverbs"). Since the uverbs extensions
functionality was experimental for v3.12, this patch re-enables the
support for them and flow-steering for v3.13.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: extended command: an improved infrastructure for uverbs commands

Commit 400dbc96583f ("IB/core: Infrastructure for extensible uverbs
commands") added an infrastructure for extensible uverbs commands
while later commit 436f2ad05a0b ("IB/core: Export ib_create/destroy_flow
through uverbs") exported ib_create_flow()/ib_destroy_flow() functions
using this new infrastructure.

According to the commit 400dbc96583f, the purpose of this
infrastructure is to support passing around provider (eg. hardware)
specific buffers when userspace issue commands to the kernel, so that
it would be possible to extend uverbs (eg. core) buffers independently
from the provider buffers.

But the new kernel command function prototypes were not modified to
take advantage of this extension. This issue was exposed by Roland
Dreier in a previous review[1].

So the following patch is an attempt to a revised extensible command
infrastructure.

This improved extensible command infrastructure distinguish between
core (eg. legacy)'s command/response buffers from provider
(eg. hardware)'s command/response buffers: each extended command
implementing function is given a struct ib_udata to hold core
(eg. uverbs) input and output buffers, and another struct ib_udata to
hold the hw (eg. provider) input and output buffers.

Having those buffers identified separately make it easier to increase
one buffer to support extension without having to add some code to
guess the exact size of each command/response parts: This should make
the extended functions more reliable.

Additionally, instead of relying on command identifier being greater
than IB_USER_VERBS_CMD_THRESHOLD, the proposed infrastructure rely on
unused bits in command field: on the 32 bits provided by command
field, only 6 bits are really needed to encode the identifier of
commands currently supported by the kernel. (Even using only 6 bits
leaves room for about 23 new commands).

So this patch makes use of some high order bits in command field to
store flags, leaving enough room for more command identifiers than one
will ever need (eg. 256).

The new flags are used to specify if the command should be processed
as an extended one or a legacy one. While designing the new command
format, care was taken to make usage of flags itself extensible.

Using high order bits of the commands field ensure that newer
libibverbs on older kernel will properly fail when trying to call
extended commands. On the other hand, older libibverbs on newer kernel
will never be able to issue calls to extended commands.

The extended command header includes the optional response pointer so
that output buffer length and output buffer pointer are located
together in the command, allowing proper parameters checking. This
should make implementing functions easier and safer.

Additionally the extended header ensure 64bits alignment, while making
all sizes multiple of 8 bytes, extending the maximum buffer size:

legacy extended

Maximum command buffer: 256KBytes 1024KBytes (512KBytes + 512KBytes)
Maximum response buffer: 256KBytes 1024KBytes (512KBytes + 512KBytes)

For the purpose of doing proper buffer size accounting, the headers
size are no more taken in account in "in_words".

One of the odds of the current extensible infrastructure, reading
twice the "legacy" command header, is fixed by removing the "legacy"
command header from the extended command header: they are processed as
two different parts of the command: memory is read once and
information are not duplicated: it's making clear that's an extended
command scheme and not a different command scheme.

The proposed scheme will format input (command) and output (response)
buffers this way:

- command:

legacy header +
extended header +
command data (core + hw):

+----------------------------------------+
| flags | 00 00 | command |
| in_words | out_words |
+----------------------------------------+
| response |
| response |
| provider_in_words | provider_out_words |
| padding |
+----------------------------------------+
| |
. <uverbs input> .
. (in_words * 8) .
| |
+----------------------------------------+
| |
. <provider input> .
. (provider_in_words * 8) .
| |
+----------------------------------------+

- response, if present:

+----------------------------------------+
| |
. <uverbs output space> .
. (out_words * 8) .
| |
+----------------------------------------+
| |
. <provider output space> .
. (provider_out_words * 8) .
| |
+----------------------------------------+

The overall design is to ensure that the extensible infrastructure is
itself extensible while begin more reliable with more input and bound
checking.

Note:

The unused field in the extended header would be perfect candidate to
hold the command "comp_mask" (eg. bit field used to handle
compatibility). This was suggested by Roland Dreier in a previous
review[2]. But "comp_mask" field is likely to be present in the uverb
input and/or provider input, likewise for the response, as noted by
Matan Barak[3], so it doesn't make sense to put "comp_mask" in the
header.

[1]:
http://marc.info/?i=CAL1RGDWxmM17W2o_era24A-TTDeKyoL6u3NRu_=t_dhV_ZA9MA@mail.gmail.com

[2]:
http://marc.info/?i=CAL1RGDXJtrc849M6_XNZT5xO1+ybKtLWGq6yg6LhoSsKpsmkYA@mail.gmail.com

[3]:
http://marc.info/?i=525C1149.6000701@mellanox.com

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Link: http://marc.info/?i=cover.1383773832.git.ydroneaud@opteya.com

[ Convert "ret ? ret : 0" to the equivalent "ret". - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Remove ib_uverbs_flow_spec structure from userspace

The structure holding any types of flow_spec is of no use to
userspace. It would be wrong for userspace to do:

struct ib_uverbs_flow_spec flow_spec;

flow_spec.type = IB_FLOW_SPEC_TCP;
flow_spec.size = sizeof(flow_spec);

Instead, userspace should use the dedicated flow_spec structure for
- Ethernet : struct ib_uverbs_flow_spec_eth,
- IPv4 : struct ib_uverbs_flow_spec_ipv4,
- TCP/UDP : struct ib_uverbs_flow_spec_tcp_udp.

In other words, struct ib_uverbs_flow_spec is a "virtual" data
structure that can only be use by the kernel as an alias to the other.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Link: http://marc.info/?i=cover.1383773832.git.ydroneaud@opteya.com
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Temporarily disable create_flow/destroy_flow uverbs

The create_flow/destroy_flow uverbs and the associated extensions to
the user-kernel verbs ABI are under review and are too experimental to
freeze at this point.

So userspace is not exposed to experimental features and an uinstable
ABI, temporarily disable this for v3.12 (with a Kconfig option behind
staging to reenable it if desired).

The feature will be enabled after proper cleanup for v3.13.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Link: http://marc.info/?i=cover.1381351016.git.ydroneaud@opteya.com
Link: http://marc.info/?i=cover.1381177342.git.ydroneaud@opteya.com

[ Add a Kconfig option to reenable these verbs. - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Export ib_create/destroy_flow through uverbs

Implement ib_uverbs_create_flow() and ib_uverbs_destroy_flow() to
support flow steering for user space applications.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/core: Fixes to XRC reference counting in uverbs

Added reference counting mechanism for XRC target QPs between
ib_uqp_object and its ib_uxrcd_object. This prevents closing an XRC
domain that is still attached to a QP. In addition, add missing code
in ib_uverbs_destroy_srq() to handle ib_uxrcd_object reference
counting correctly when destroying an xsrq.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/uverbs: Implement memory windows support in uverbs

The existing user/kernel uverbs API has IB_USER_VERBS_CMD_ALLOC/DEALLOC_MW.
Implement these calls, along with destroying user memory windows during
process cleanup.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Shani Michaeli <shanim@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

RDMA/uverbs: Export ib_open_qp() capability to user space

Allow processes that share the same XRC domain to open an existing
shareable QP. This permits those processes to receive events on the
shared QP and transfer ownership, so that any process may modify the
QP. The latter allows the creating process to exit, while a remaining
process can still transition it for path migration purposes.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

RDMA/uverbs: Export XRC SRQs to user space

We require additional information to create XRC SRQs than we can
exchange using the existing create SRQ ABI. Provide an enhanced create
ABI for extended SRQ types.

Based on patches by Jack Morgenstein <jackm@dev.mellanox.co.il>
and Roland Dreier <roland@purestorage.com>

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

RDMA/uverbs: Export XRC domains to user space

Allow user space to create XRC domains. Because XRCDs are expected to
be shared among multiple processes, we use inodes to identify an XRCD.

Based on patches by Jack Morgenstein <jackm@dev.mellanox.co.il>

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

switch infiniband uverbs to anon_inodes

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

IB/uverbs: Pack struct ib_uverbs_event_file tighter

Eliminate some padding in the structure by rearranging the members.
sizeof(struct ib_uverbs_event_file) is now 72 bytes (from 80) and
more members now fit in the first cacheline.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Convert *cdev to cdev in struct ib_uverbs_device

Instead of storing a pointer to a cdev, embed the entire struct cdev.

This change allows us to use the container_of() macro in
ib_uverbs_open() in a future patch.

This change increases the size of struct ib_uverbs_device to 168 bytes
across 3 cachelines from 80 bytes in 2 cachelines. However, we
rearrange the members so that everything fits into the first cacheline
except for the struct cdev. Finally, we don't touch the cdev in any
fastpaths, so this change shouldn't negatively affect performance.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

RDMA: Remove subversion $Id tags

They don't get updated by git and so they're worse than useless.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB: convert struct class_device to struct device

This converts the main ib_device to use struct device instead of struct
class_device as class_device is going away.

Signed-off-by: Tony Jones <tonyj@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

IB/uverbs: Don't store struct file * for event files

The file member of struct ib_uverbs_event_file was only used to keep
track of whether the file had been closed or not. The only thing we
ever did with the value was check if it was NULL or not. Simplify the
code and get rid of the need to keep track of the struct file * we
allocate by replacing the file member with an is_closed member.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Make ib_uverbs_release_event_file() static

ib_uverbs_release_event_file() is only used in uverbs_main.c, so make it
static to that file. Also move the definition before the first use, so
a forward declaration is not needed.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Export ib_umem_get()/ib_umem_release() to modules

Export ib_umem_get()/ib_umem_release() and put low-level drivers in
control of when to call ib_umem_get() to pin and DMA map userspace,
rather than always calling it in ib_uverbs_reg_mr() before calling the
low-level driver's reg_user_mr method.

Also move these functions to be in the ib_core module instead of
ib_uverbs, so that driver modules using them do not depend on
ib_uverbs.

This has a number of advantages:
- It is better design from the standpoint of making generic code a
library that can be used or overridden by device-specific code as
the details of specific devices dictate.
- Drivers that do not need to pin userspace memory regions do not
need to take the performance hit of calling ib_mem_get(). For
example, although I have not tried to implement it in this patch,
the ipath driver should be able to avoid pinning memory and just
use copy_{to,from}_user() to access userspace memory regions.
- Buffers that need special mapping treatment can be identified by
the low-level driver. For example, it may be possible to solve
some Altix-specific memory ordering issues with mthca CQs in
userspace by mapping CQ buffers with extra flags.
- Drivers that need to pin and DMA map userspace memory for things
other than memory regions can use ib_umem_get() directly, instead
of hacks using extra parameters to their reg_phys_mr method. For
example, the mlx4 driver that is pending being merged needs to pin
and DMA map QP and CQ buffers, but it does not need to create a
memory key for these buffers. So the cleanest solution is for mlx4
to call ib_umem_get() in the create_qp and create_cq methods.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Avoid a crash on device hot remove

Wait until all users have closed their device context before allowing
device unregistration to complete. This prevents a crash caused by
referring to stale data structures.

A better solution would be to have a way to revoke contexts rather
than waiting for userspace to close the context, but that's a much
bigger change that will have to wait. For now let's at least avoid
the crash.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Don't serialize with ib_uverbs_idr_mutex

Currently, all userspace verbs operations that call into the kernel
are serialized by ib_uverbs_idr_mutex. This can be a scalability
issue for some workloads, especially for devices driven by the ipath
driver, which needs to call into the kernel even for datapath
operations.

Fix this by adding reference counts to the userspace objects, and then
converting ib_uverbs_idr_mutex into a spinlock that only protects the
idrs long enough to take a reference on the object being looked up.
Because remove operations may fail, we have to do a slightly funky
two-step deletion, which is described in the comments at the top of
uverbs_cmd.c.

This also still leaves ib_uverbs_idr_lock as a single lock that is
possibly subject to contention. However, the lock hold time will only
be a single idr operation, so multiple threads should still be able to
make progress, even if ib_uverbs_idr_lock is being ping-ponged.

Surprisingly, these changes even shrink the object code:

add/remove: 23/5 grow/shrink: 4/21 up/down: 633/-693 (-60)

Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Support for query SRQ from userspace

Add support to uverbs to handle querying userspace SRQs (shared
receive queues), including adding an ABI for marshalling requests and
responses. The kernel midlayer already has the underlying
ib_query_srq() function.

Signed-off-by: Dotan Barak <dotanb@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: Support for query QP from userspace

Add support to uverbs to handle querying userspace QPs (queue pairs),
including adding an ABI for marshalling requests and responses. The
kernel midlayer already has the underlying ib_query_qp() function.

Signed-off-by: Dotan Barak <dotanb@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB: Add userspace support for resizing CQs

Add support to uverbs to handle resizing userspace CQs (completion
queues), including adding an ABI for marshalling requests and
responses. The kernel midlayer already has ib_resize_cq().

Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB: convert from semaphores to mutexes

semaphore to mutex conversion by Ingo and Arjan's script.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
[ Sanity-checked on real IB hardware ]
Signed-off-by: Roland Dreier <rolandd@cisco.com>

IB/uverbs: track multicast group membership for userspace QPs

uverbs needs to track which multicast groups is each qp
attached to, in order to properly detach when cleanup
is performed on device file close.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

[IB] uverbs: Avoid NULL pointer deref on CQ async event

Userspace CQs that have no completion event channel attached end up
with their cq_context set to NULL. However, asynchronous events like
"CQ overrun" can still occur on such CQs, so add a uverbs_file member
to struct ib_ucq_object that we can follow to deliver these events.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[IB] uverbs: Fix device lifetime problems

Move ib_uverbs module to using cdev_alloc() and class_device_create()
so that we can handle device lifetime properly. Now we can make sure
we keep all of our data structures around until the last way to reach
them is gone.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[IB] uverbs: Implement more commands

Add kernel support for userspace calling poll CQ, request CQ
notification, post send, post receive, post SRQ receive, create AH and
destroy AH commands. These commands allow us to support userspace
verbs for devices that can't perform these operations directly from
userspace (eg the PathScale HCA).

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[IB] uverbs: ABI-breaking fixes for userspace verbs

Introduce new userspace verbs ABI version 3. This eliminates some
unneeded commands, and adds support for user-created completion
channels. This cleans up problems with file leaks on error paths, and
also makes sure that file descriptors are always installed into the
correct process.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[IB] uverbs: Close some exploitable races

Al Viro pointed out that the current IB userspace verbs interface
allows userspace to cause mischief by closing file descriptors before
we're ready, or issuing the same command twice at the same time. This
patch closes those races, and fixes other obvious problems such as a
module reference leak.

Some other interface bogosities will require an ABI change to fix
properly, so I'm deferring those fixes until 2.6.15.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

Make sure that userspace does not retrieve stale asynchronous or
completion events after destroying a CQ, QP or SRQ. We do this by
sweeping the event lists before returning from a destroy calls, and
then return the number of events already reported before the destroy
call. This allows userspace wait until it has processed all events
for an object returned from the kernel before it frees its context for
the object.

The ABI of the destroy CQ, destroy QP and destroy SRQ commands has to
change to return the event count, so bump the ABI version from 1 to 2.
The userspace libibverbs library has already been updated to handle
both the old and new ABI versions.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[PATCH] IB: move include files to include/rdma

Move the InfiniBand headers from drivers/infiniband/include to include/rdma.
This allows InfiniBand-using code to live elsewhere, and lets us remove the
ugly EXTRA_CFLAGS include path from the InfiniBand Makefiles.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[PATCH] IB: userspace SRQ support

Add SRQ support to userspace verbs module. This adds several commands
and associated structures, but it's OK to do this without bumping the
ABI version because the commands are added at the end of the list so
they don't change the existing numbering. There are two cases to
worry about:

1. New kernel, old userspace. This is OK because old userspace simply
won't try to use the new SRQ commands. None of the old commands are
changed.

2. Old kernel, new userspace. This works perfectly as long as
userspace doesn't try to use SRQ commands. If userspace tries to
use SRQ commands, it will get EINVAL, which is perfectly
reasonable: the kernel doesn't support SRQs, so we couldn't do any
better.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[PATCH] IB: Add copyright notices

Make some lawyers happy and add copyright notices for people who
forgot to include them when they actually touched the code.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

[IB/uverbs]: Add O_ASYNC support

Add support for O_ASYNC notifications on userspace verbs
completion and asynchronous event file descriptors.

Signed-off-by: Gleb Natapov <glebn@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

[PATCH] IB uverbs: core implementation

Add the core of the InfiniBand userspace verbs implementation, including
creating character device nodes, dispatching requests from userspace, and
passing event notifications back up to userspace.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>