RDMA/uverbs: Avoid -Wflex-array-member-not-at-end warnings

-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.

There are currently a couple of objects (`alloc_head` and `bundle`) in
`struct bundle_priv` that contain a couple of flexible structures:

struct bundle_priv {
/* Must be first */
struct bundle_alloc_head alloc_head;

...

/*
* Must be last. bundle ends in a flex array which overlaps
* internal_buffer.
*/
struct uverbs_attr_bundle bundle;
u64 internal_buffer[32];
};

So, in order to avoid ending up with a couple of flexible-array members
in the middle of a struct, we use the `struct_group_tagged()` helper to
separate the flexible array from the rest of the members in the flexible
structures:

struct uverbs_attr_bundle {
struct_group_tagged(uverbs_attr_bundle_hdr, hdr,
... the rest of the members
);
struct uverbs_attr attrs[];
};

With the change described above, we now declare objects of the type of
the tagged struct without embedding flexible arrays in the middle of
another struct:

struct bundle_priv {
/* Must be first */
struct bundle_alloc_head_hdr alloc_head;

...

struct uverbs_attr_bundle_hdr bundle;
u64 internal_buffer[32];
};

We also use `container_of()` whenever we need to retrieve a pointer
to the flexible structures.

Notice that the `bundle_size` computed in `uapi_compute_bundle_size()`
remains the same.

So, with these changes, fix the following warnings:

drivers/infiniband/core/uverbs_ioctl.c:45:34: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
45 | struct bundle_alloc_head alloc_head;
| ^~~~~~~~~~
drivers/infiniband/core/uverbs_ioctl.c:67:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
67 | struct uverbs_attr_bundle bundle;
| ^~~~~~

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/ZeIgeZ5Sb0IZTOyt@neat
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

rdma: fix INFINIBAND_USER_ACCESS dependency

After a change to the bnxt_re driver, it fails to link when
CONFIG_INFINIBAND_USER_ACCESS is disabled:

aarch64-linux-ld: drivers/infiniband/hw/bnxt_re/ib_verbs.o: in function `bnxt_re_handler_BNXT_RE_METHOD_ALLOC_PAGE':
ib_verbs.c:(.text+0xd64): undefined reference to `ib_uverbs_get_ucontext_file'
aarch64-linux-ld: drivers/infiniband/hw/bnxt_re/ib_verbs.o:(.rodata+0x168): undefined reference to `uverbs_idr_class'
aarch64-linux-ld: drivers/infiniband/hw/bnxt_re/ib_verbs.o:(.rodata+0x1a8): undefined reference to `uverbs_destroy_def_handler'

The problem is that the 'bnxt_re_uapi_defs' structure is built
unconditionally and references a couple of functions that are never
really called in this configuration but instead require other functions
that are left out.

Adding an #ifdef around the new code, or a Kconfig dependency would
address this problem, but adding the compile-time check inside of the
UAPI_DEF_CHAIN_OBJ_TREE_NAMED() macro seems best because that also
addresses the problem in other drivers that may run into the same
dependency.

Fixes: 360da60d6c6ed ("RDMA/bnxt_re: Enable low latency push")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

RDMA/core: Add UVERBS_ATTR_RAW_FD

This uses the same passing protocol as UVERBS_ATTR_FD (eg len = 0 data_s64
= fd), except that the FD is not required to be a uverbs object and the
core code does not covert the FD to an object handle automatically.

Access to the int fd is provided by uverbs_get_raw_fd().

Link: https://lore.kernel.org/r/2-v1-bd147097458e+ede-umem_dmabuf_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

RDMA/uverbs: Fix -Wunused-function warning

make W=1 warns this:

In file included from drivers/infiniband/sw/rdmavt/mmap.c:51:0:
./include/rdma/uverbs_ioctl.h:937:1:
warning: ‘_uverbs_get_const_unsigned’ defined but not used [-Wunused-function]
_uverbs_get_const_unsigned(u64 *to,
^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/rdma/uverbs_ioctl.h:930:1:
warning: ‘_uverbs_get_const_signed’ defined but not used [-Wunused-function]
_uverbs_get_const_signed(s64 *to, const struct uverbs_attr_bundle *attrs_bundle,
^~~~~~~~~~~~~~~~~~~~~~~~

Make these functions inline to fix this warnings.

Fixes: 2904bb37b35d ("IB/core: Split uverbs_get_const/default to consider target type")
Link: https://lore.kernel.org/r/20210401021028.25720-1-yuehaibing@huawei.com
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/core: Split uverbs_get_const/default to consider target type

Change uverbs_get_const/uverbs_get_const_default to work properly with
both signed/unsigned parameters.

Current APIs mix s64 and u64 which leads to incorrect check when u64
value was supplied and its upper bit was set. In that case
uverbs_get_const() / uverbs_get_const_default() lower bound check may
fail unexpectedly, target is unsigned (lower bound is 0) but value
became negative as of the s64 usage.

Split to have two different APIs, no change to callers as the required
API will be called internally according to the target type.

Link: https://lore.kernel.org/r/20210304130501.1102577-3-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

RDMA/uverbs: Fix incorrect variable type

Fix incorrect type of max_entries in UVERBS_METHOD_QUERY_GID_TABLE -
max_entries is of type size_t although it can take negative values.

The following static check revealed it:

drivers/infiniband/core/uverbs_std_types_device.c:338 ib_uverbs_handler_UVERBS_METHOD_QUERY_GID_TABLE() warn: 'max_entries' unsigned <= 0

Fixes: 9f85cbe50aa0 ("RDMA/uverbs: Expose the new GID query API to user space")
Link: https://lore.kernel.org/r/20201208073545.9723-4-leon@kernel.org
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

IB/verbs: avoid nested container_of()

Nested container_of() calls work correctly but cause a warning when
building with W=2. Invoking it from an inline function like in
drivers/infiniband/hw/mlx5/mlx5_ib.h means we get hundreds of warnings
like:

include/linux/kernel.h:852:8: warning: declaration of '__mptr' shadows a previous local [-Wshadow]
852 | void *__mptr = (void *)(ptr); \
| ^~~~~~
include/rdma/uverbs_ioctl.h:651:11: note: in expansion of macro 'container_of'
651 | (udata ? container_of(container_of(udata, struct uverbs_attr_bundle, \
| ^~~~~~~~~~~~
include/rdma/uverbs_ioctl.h:651:24: note: in expansion of macro 'container_of'
651 | (udata ? container_of(container_of(udata, struct uverbs_attr_bundle, \
| ^~~~~~~~~~~~
drivers/infiniband/hw/mthca/mthca_qp.c:564:35: note: in expansion of macro 'rdma_udata_to_drv_context'
564 | struct mthca_ucontext *context = rdma_udata_to_drv_context(
| ^~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/kernel.h:852:8: note: shadowed declaration is here
852 | void *__mptr = (void *)(ptr); \
| ^~~~~~
include/rdma/uverbs_ioctl.h:651:11: note: in expansion of macro 'container_of'
651 | (udata ? container_of(container_of(udata, struct uverbs_attr_bundle, \
| ^~~~~~~~~~~~
drivers/infiniband/hw/mthca/mthca_qp.c:564:35: note: in expansion of macro 'rdma_udata_to_drv_context'
564 | struct mthca_ucontext *context = rdma_udata_to_drv_context(
| ^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from <command-line>:
include/linux/kernel.h:852:8: warning: declaration of '__mptr' shadows a previous local [-Wshadow]
852 | void *__mptr = (void *)(ptr); \
| ^~~~~~

Rewrite the macro to use an inline function internally, which makes it
more readable and reduces the amount of useless output from make W=2.

Fixes: 730623f4a56f ("IB/verbs: Add helper function rdma_udata_to_drv_context")
Link: https://lore.kernel.org/r/20201026161549.3709175-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

RDMA/include: Replace license text with SPDX tags

The header files in RDMA subsystem are dual licensed and can be
described by simple SPDX tag, so replace all of them at once
together with making them use the same coding style for header
guard defines.

Link: https://lore.kernel.org/r/20200719072521.135260-1-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

RDMA/core: Align abort/commit object scheme for write() and ioctl() paths

Create the same logic flow for the write() interface as we have for the
ioctl() path by making sure that the object is committed or aborted
automatically after HW object creation.

Link: https://lore.kernel.org/r/20200719052223.75245-2-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

RDMA/core: Use offsetofend() instead of open coding

No reason to open code this.

Link: https://lore.kernel.org/r/0-v1-0bc346e08476+585-drop_offsetofend_jgg@mellanox.com
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Use sizeof_field() helper

Make use of the sizeof_field() helper instead of an open-coded version.

Link: https://lore.kernel.org/r/20200527144152.GA22605@embeddedor
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/core: Allow the ioctl layer to abort a fully created uobject

While creating a uobject every create reaches a point where the uobject is
fully initialized. For ioctls that go on to copy_to_user this means they
need to open code the destruction of a fully created uobject - ie the
RDMA_REMOVE_DESTROY sort of flow.

Open coding this creates bugs, eg the CQ does not properly flush the
events list when it does its error unwind.

Provide a uverbs_finalize_uobj_create() function which indicates that the
uobject is fully initialized and that abort should call to destroy_hw to
destroy the uobj->object and related.

Methods can call this function if they go on to have error cases after
setting uobj->object. Once done those error cases can simply do return,
without an error unwind.

Link: https://lore.kernel.org/r/20200519072711.257271-2-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>

IB/mlx5: Expose UAR object and its alloc/destroy commands

Expose UAR object and its alloc/destroy commands to be used over the ioctl
interface by user space applications.

This API supports both BF & NC modes and enables a dynamic allocation of
UARs once really needed.

As the number of driver objects were limited by the core ones when the
merged tree is prepared, had to decrease the number of core objects to
enable the new UAR object usage.

Link: https://lore.kernel.org/r/20200324060143.1569116-2-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Michael Guralnik <michaelgur@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/verbs: Add helper function rdma_udata_to_drv_context

Helper function to get driver's context out of ib_udata wrapped in
uverbs_attr_bundle for user objects or NULL for kernel objects.

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

IB/uverbs: Add ib_ucontext to uverbs_attr_bundle sent from ioctl and cmd flows

Add ib_ucontext to the uverbs_attr_bundle sent down the iocl and cmd flows
as soon as the flow has ib_uobject.

In addition, remove rdma_get_ucontext helper function that is only used by
ib_umem_get.

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

IB/core: uverbs copy to struct or zero helper

Add a helper to zero fill fields before copying data to
UVERBS_ATTR_STRUCT.

As UVERBS_ATTR_STRUCT can be used as an extensible struct, we want to make
sure that if the user supplies us with a struct that has new fields that
we are not aware of, we return them zeroed to the user.

This helper should be used when using UVERBS_ATTR_STRUCT for an extendable
data structure and there is a need to make sure that extended members of
the struct, that the kernel doesn't handle, are returned zeroed to the
user. This is needed due to the fact that UVERBS_ATTR_STRUCT allows
non-zero values for members after 'last' member.

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

IB/uverbs: Add helper to get array size from ptr attribute

When the parser of an ioctl command has the knowledge that a ptr attribute
in a bundle represents an array of structures, it is useful for it to know
the number of elements in the array. This is done by dividing the
attribute length with the element size.

Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Guy Levi <guyle@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA: Start use ib_device_ops

Make all the required change to start use the ib_device_ops structure.

Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/mlx5: Fail early if user tries to create flows on IB representors

IB representors don't support creation of RAW ethernet QP flows. Disable
them by reusing existing RDMA/core support macros. We do it for both
creation and matcher because latter is not usable if no flow creation is
available.

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

IB/core: Introduce UVERBS_IDR_ANY_OBJECT

Introduce the UVERBS_IDR_ANY_OBJECT type to match any IDR object.

Once used, the infrastructure skips checking for the IDR type, it
becomes the driver handler responsibility.

This enables drivers to get in a given method an object from various of
types.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

RDMA/uverbs: Use only attrs for the write() handler signature

All of the old arguments can be derived from the uverbs_attr_bundle
structure, so get rid of the redundant arguments. Most of the prior work
has been removing users of the arguments to allow this to be a simple
patch.

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: Use uverbs_attr_bundle to pass ucore for write/write_ex

This creates a consistent way to access the two core buffers across write
and write_ex handlers.

Remove the open coded ucore conversion in the write/ex compatibility
handlers.

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: Use uverbs_attr_bundle to pass udata for ioctl()

Have the core code initialize the driver_udata if the method has a udata
description. This is done using the same create_udata the handler was
supposed to call.

This makes ioctl consistent with the write and write_ex paths.

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

RDMA/uverbs: Use uverbs_attr_bundle to pass udata for write_ex

The core code needs to compute the udata so we may as well pass it in the
uverbs_attr_bundle instead of on the stack. This converts the simple case
of write_ex() which already has a core calculation.

Also change the write() path to use the attrs for ib_uverbs_init_udata()
instead of on the stack. This lets the write to write_ex compatibility
path continue to follow the lead of the _ex path.

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

RDMA/uverbs: Add structure size info to write commands

We need the structure sizes to compute the location of the udata in the
core code. Annotate the sizes into the new macro language.

This is generated largely by script and checked by comparing against the
similar list in rdma-core.

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

RDMA/uverbs: Do not pass ib_uverbs_file to ioctl methods

The uverbs_attr_bundle already contains this pointer, and most methods
don't actually need it. Get rid of the redundant function argument.

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

RDMA/uverbs: Make write() handlers return 0 on success

Currently they return the command length, while all other handlers return
0. This makes the write path closer to the write_ex and ioctl path.

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

RDMA/uverbs: Replace ib_uverbs_file with uverbs_attr_bundle for write

Now that we can add meta-data to the description of write() methods we
need to pass the uverbs_attr_bundle into all write based handlers so
future patches can use it as a container for any new data transferred out
of the core.

This is the first step to bringing the write() and ioctl() methods to a
common interface signature.

This is a simple search/replace, and we push the attr down into the uobj
and other APIs to keep changes minimal.

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

RDMA/uverbs: Check for NULL driver methods for every write call

Add annotations to the uverbs_api structure indicating which driver
methods are called by the implementation. If the required method
is NULL the write API will be not be callable.

This effectively duplicates the cmd_mask system, however it does it by
expressing invariants required by the core code, not by delegating
decision making to the driver. This is another step toward eliminating
cmd_mask.

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

RDMA/verbs: Store the write/write_ex uapi entry points in the uverbs_api

Bringing all uapi entry points into one place lets us deal with them
consistently. For instance the write, write_ex and ioctl paths can be
disabled when an API is not supported by the driver.

This will replace the uverbs_cmd_table static arrays.

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

RDMA/uverbs: Add helpers to mark uapi functions as unsupported

We have many cases where parts of the uapi are not supported in a driver,
needs a certain protocol, or whatever. It is best to reflect this directly
into the struct uverbs_api when it is built so that everything is simply
blocked off, and future introspection can report a proper supported list.

This is done by adding some additional helpers to the definition list
language that disable objects based on a 'supported' call back, and a
helper that disables based on a NULL struct ib_device function pointer.

Disablement is global. For instance, if a driver disables an object then
everything connected to that object is removed, including core methods.

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

RDMA/uverbs: Use a linear list to describe the compiled-in uapi

The 'tree' data structure is very hard to build at compile time, and this
makes it very limited. The new radix tree based compiler can handle a more
complex input language that does not require the compiler to perfectly
group everything into a neat tree structure.

Instead use a simple list to describe to input, where the list elements
can be of various different 'opcodes' instructing the radix compiler what
to do. Start out with opcodes chaining to other definition lists and
chaining to the existing 'tree' definition.

Replace the very top level of the 'object tree' with this list type and
get rid of struct uverbs_object_tree_def and DECLARE_UVERBS_OBJECT_TREE.

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

IB/uverbs: Add IDRs array attribute type to ioctl() interface

Methods sometimes need to get a flexible set of IDRs and not a strict set
as can be achieved today by the conventional IDR attribute. Add a new
IDRS_ARRAY attribute to the generic uverbs ioctl layer.

IDRS_ARRAY points to array of idrs of the same object type and same access
rights, only write and read are supported.

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

RDMA/uverbs: Add UVERBS_ATTR_CONST_IN to the specs language

This makes it clear and safe to access constants passed in from user
space. We define a consistent ABI of u64 for all constants, and verify
that the data passed in can be represented by the type the user supplies.

The expectation is this will always be used with an enum declaring the
constant values, and the user will use the enum type as input to the
accessor.

To retrieve the attribute value we introduce two helper calls - one
standard which may fail if attribute is not valid and one where caller can
provide a default value which will be used in case the attribute is not
valid (useful when attribute is optional).

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@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: Use uverbs_api to unmarshal ioctl commands

Convert the ioctl method syscall path to use the uverbs_api data
structures. The new uapi structure includes all the same information, just
in a different and more optimal way.

- Use attr_bkey instead of 2 level radix trees for everything related to
attributes. This includes the attribute storage, presence, and
detection of missing mandatory attributes.
- Avoid iterating over all attribute storage at finish, instead use
find_first_bit with the attr_bkey to locate only those attrs that need
cleanup.
- Organize things to always run, and always rely on, cleanup. This
avoids a bunch of tricky error unwind cases.
- Locate the method using the radix tree, and locate the attributes
using a very efficient incremental radix tree lookup
- Use the precomputed destroy_bkey to handle uobject destruction
- Use the precomputed allocation sizes and precomputed 'need_stack'
to avoid maths in the fast path. This is optimal if userspace
does not pass (many) unsupported attributes.

Overall this results in much better codegen for the attribute accessors,
everything is now stored in bitmaps or linear arrays indexed by attr_bkey.
The compiler can compute attr_bkey values at compile time for all method
attributes, meaning things like uverbs_attr_is_valid() now compile into
single instruction bit tests.

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

IB/uverbs: Add a simple allocator to uverbs_attr_bundle

This is similar in spirit to devm, it keeps track of any allocations
linked to this method call and ensures they are all freed when the method
exits. Further, if there is space in the internal/onstack buffer then the
allocator will hand out that memory and avoid an expensive call to
kalloc/kfree in the syscall path.

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

IB/uverbs: Remove the ib_uverbs_attr pointer from each attr

Memory in the bundle is valuable, do not waste it holding an 8 byte
pointer for the rare case of writing to a PTR_OUT. We can compute the
pointer by storing a small 1 byte array offset and the base address of the
uattr memory in the bundle private memory.

This also means we can access the kernel's copy of the ib_uverbs_attr, so
drop the copy of flags as well.

Since the uattr base should be private bundle information this also
de-inlines the already too big uverbs_copy_to inline and moves
create_udata into uverbs_ioctl.c so they can see the private struct
definition.

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

IB/uverbs: Provide implementation private memory for the uverbs_attr_bundle

This already existed as the anonymous 'ctx' structure, but this was not
really a useful form. Hoist this struct into bundle_priv and rework the
internal things to use it instead.

Move a bunch of the processing internal state into the priv and reduce the
excessive use of function arguments.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@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 pass struct ib_device to the ioctl methods

This does the same as the patch before, except for ioctl. The rules are
the same, but for the ioctl methods the core code handles setting up the
uobject.

- Retrieve the ib_dev from the uobject->context->device. This is
safe under ioctl as the core has already done rdma_alloc_begin_uobject
and so CREATE calls are entirely protected by the rwsem.
- Retrieve the ib_dev from uobject->object
- Call ib_uverbs_get_ucontext()

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

IB/uverbs: Add UVERBS_ATTR_FLAGS_IN to the specs language

This clearly indicates that the input is a bitwise combination of values
in an enum, and identifies which enum contains the definition of the bits.

Special accessors are provided that handle the mandatory validation of the
allowed bits and enforce the correct type for bitwise flags.

If we had introduced this at the start then the kabi would have uniformly
used u64 data to pass flags, however today there is a mixture of u64 and
u32 flags. All places are converted to accept both sizes and the accessor
fixes it. This allows all existing flags to grow to u64 in future without
any hassle.

Finally all flags are, by definition, optional. If flags are not passed
the accessor does not fail, but provides a value of zero.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@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/mlx5: Introduce flow steering matcher uapi object

Introduce flow steering matcher object and its create and destroy methods.

This matcher object holds some mlx5 specific driver properties that
matches the underlay device specification when an mlx5 flow steering group
is created.

It will be used in downstream patches to be part of mlx5 specific create
flow method.

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: Combine MIN_SZ_OR_ZERO with UVERBS_ATTR_STRUCT

After all the rework is done it is now possible to include single flags in
the type macros. Any user of UVERBS_ATTR_STRUCT needs to zero check data
past the end of the known struct to be correct, so make this mandatory,
and get rid of MIN_SZ_OR_ZERO as a user flag.

This changes UVERBS_ATTR_TYPE to refer to a struct of exact size with not
possibility of extension, convert the few users of UVERBS_ATTR_TYPE and
MIN_SZ_OR_ZERO to use UVERBS_ATTR_STRUCT.

The one user of UVERBS_ATTR_STRUCT without MIN_SZ_OR_ZERO is just
confused. There is some padding at the end of that struct, but userspace
always provides it with the padding. The construction doesn't test if the
padding is zero, so it is pointless. Just use UVERBS_ATTR_TYPE.

Finally, rename min_sz_or_zero to zero_trailing to better reflect what it
does and hopefully avoid such mis-uses in the future.

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

RDMA/uverbs: Use UVERBS_ATTR_MIN_SIZE correctly and uniformly

This newer macro allows specifying a lower bound on the accepted size, and
has an 'unlimited' upper bound. Due to this it never checks for trailing
zeroing so it doesn't make any sense to combine it with MIN_SZ_OR_ZERO, so
drop MIN_SZ_OR_ZERO when they are used together

There were a couple of places that open coded this pattern, switch them to
use the clearer UVERBS_ATTR_MIN_SIZE for clarity.

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

RDMA/uverbs: Remove UA_FLAGS

This bit of boilerplate isn't really necessary, we can use bitfields
instead of a flags enum and the macros can then individually initialize
them through the __VA_ARGS__ like everything else.

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

RDMA/uverbs: Get rid of the & in method specifications

Hide it inside the macros. The & is confusing and interferes with using
this as a generic DSL in later patches.

Since this also touches almost every line, also run the specs through
clang-format (with 'BinPackParameters: false') to make the maintenance
easier.

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>

RDMA/uverbs: Simplify method definition macros

Instead of the large set of indirecting macros, define the few needed
macros to directly instantiate the struct uverbs_method_def and associated
attributes 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>

RDMA/uverbs: Simplify UVERBS_ATTR family of macros

Instead of using a complex cascade of macros, just directly provide the
initializer list each of the declarations is trying to create.

Now that the macros are simplified this also reworks the uverbs_attr_spec
to be friendly to older compilers by eliminating any unnamed
structures/unions inside, and removing the duplication of some fields. The
structure size remains at 16 bytes which was the original motivation for
some of this oddness.

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

IB/uverbs: Delete type and id from uverbs_obj_attr

In this context the uobject is not allowed to be NULL, so type is the same
as uobject->type, and at least for IDR, id is the same as uobject->id.

FD objects should never handle the FD number outside the uAPI boundary
code.

Suggested-by: Guy Levi <guyle@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Add a macro to define a type with no kernel known size

Sometimes the uverbs uAPI doesn't really care about the structure it gets
from user-space. All it wants to do is to allocate enough space and send
it to the hardware/provider driver. Adding a UVERBS_ATTR_MIN_SIZE that
could be used for this scenarios. We use USHRT_MAX as the kernel known
size to bypass any zero validations.

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 PTR_IN attributes that are allocated/copied automatically

Adding UVERBS_ATTR_SPEC_F_ALLOC_AND_COPY flag to PTR_IN attributes.
By using this flag, the parse automatically allocates and copies the
user-space data. This data is accessible by using uverbs_attr_get_len
and uverbs_attr_get_alloced_ptr inline accessor functions from the
handler.

Signed-off-by: Matan Barak <matanb@mellanox.com>
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 an ib_uobject getter to ioctl() infrastructure

Previously, the user had to dig inside the attribute to get the uobject.
Add a helper function that correctly extract it (and do the required
checks) for him/her.

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

IB/uverbs: Fix uverbs_attr_get_obj

The err pointer comes from uverbs_attr_get, not from the uobject member,
which does not store an ERR_PTR.

Fixes: be934cca9e98 ("IB/uverbs: Add device memory registration ioctl support")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>

IB/uverbs: Add device memory registration ioctl support

Adding new ioctl method for the MR object - REG_DM_MR.

This command can be used by users to register an allocated
device memory buffer as an MR and receive lkey and rkey
to be used within work requests.

It is added as a new method under the MR object and using a new
ib_device callback - reg_dm_mr.
The command creates a standard ib_mr object which represents the
registered memory.

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: Add enum attribute type to ioctl() interface

Methods sometimes need to get one attribute out of a group of
pre-defined attributes. This is an enum-like behavior. Since
this is a common requirement, we add a new ENUM attribute to the
generic uverbs ioctl() layer. This attribute is embedded in methods,
like any other attributes we currently have. ENUM attributes point to
an array of standard UVERBS_ATTR_PTR_IN. The user-space encodes the
enum's attribute id in the id field and the internal PTR_IN attr id in
the enum_data.elem_id field. This ENUM attribute could be shared by
several attributes and it can get UVERBS_ATTR_SPEC_F_MANDATORY flag,
stating this attribute must be supported by the kernel, like any other
attribute.

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: Safely extend existing attributes

Previously, we've used UVERBS_ATTR_SPEC_F_MIN_SZ for extending existing
attributes. The behavior of this flag was the kernel accepts anything
bigger than the minimum size it specified. This is unsafe, since in
order to safely extend an attribute, we need to make sure unknown size
is zeroed. Replacing UVERBS_ATTR_SPEC_F_MIN_SZ with
UVERBS_ATTR_SPEC_F_MIN_SZ_OR_ZERO, which essentially checks that the
unknown size is zero. In addition, attributes are now decorated with
UVERBS_ATTR_TYPE and UVERBS_ATTR_STRUCT, so we can provide the minimum
and known length.

Users of this flag needs to use copy_from_or_zero functions/macros.

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: Enable compact representation of uverbs_attr_spec

Downstream patches extend uverbs_attr_spec with new fields.
In order to save space, we move the type and flags fields to
the various attribute flavors contained in the union.

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: Use u64_to_user_ptr() not a union

The union approach will get the endianness wrong sometimes if the kernel's
pointer size is 32 bits resulting in EFAULTs when trying to copy to/from
user.

Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/uverbs: Always use the attribute size provided by the user

This fixes several bugs around the copy_to/from user path:
- copy_to used the user provided size of the attribute
and could copy data beyond the end of the kernel buffer into
userspace.
- copy_from didn't know the size of the kernel buffer and
could have left kernel memory unexpectedly un-initialized.
- copy_from did not use the user length to determine if the
attribute data is inlined or not.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.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: Add legacy driver's user-data

In this phase, we don't want to change all the drivers to use
flexible driver's specific attributes. Therefore, we add two default
attributes: UHW_IN and UHW_OUT. These attributes are optional in some
methods and they encode the driver specific command data. We add
a function that extract this data and creates the legacy udata over
it.

Driver's data should start from UVERBS_UDATA_DRIVER_DATA_FLAG. This
turns on the first bit of the namespace, indicating this attribute
belongs to the driver's namespace.

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 macros for declaring methods and attributes

This patch adds macros for declaring objects, methods and
attributes. These definitions are later used by downstream patches
to declare some of the default types.

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 uverbs merge trees functionality

Different drivers support different features and even subset of the
common uverbs implementation. Currently, this is handled as bitmask
in every driver that represents which kind of methods it supports, but
doesn't go down to attributes granularity. Moreover, drivers might
want to add their specific types, methods and attributes to let
their user-space counter-parts be exposed to some more efficient
abstractions. It means that existence of different features is
validated syntactically via the parsing infrastructure rather than
using a complex in-handler logic.

In order to do that, we allow defining features and abstractions
as parsing trees. These per-feature parsing tree could be merged
to an efficient (perfect-hash based) parsing tree, which is later
used by the parsing infrastructure.

To sum it up, this makes a parse tree unique for a device and
represents only the features this particular device supports.
This is done by having a root specification tree per feature.
Before a device registers itself as an IB device, it merges
all these trees into one parsing tree. This parsing tree
is used to parse all user-space commands.

A future user-space application could read this parse tree. This
tree represents which objects, methods and attributes are
supported by this device.

This is based on the idea of
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

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 DEVICE object and root tree structure

This adds the DEVICE object. This object supports creating the context
that all objects are created from. Moreover, it supports executing
methods which are related to the device itself, such as QUERY_DEVICE.
This is a singleton object (per file instance).

All standard objects are put in the root structure. This root will later
on be used in drivers as the source for their whole parsing tree.
Later on, when new features are added, these drivers could mix this root
with other customized objects.

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: Declare an object instead of declaring only type attributes

Switch all uverbs_type_attrs_xxxx with DECLARE_UVERBS_OBJECT
macros. This will be later used in order to embed the object
specific methods in the objects as well.

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 new ioctl interface

In this ioctl interface, processing the command starts from
properties of the command and fetching the appropriate user objects
before calling the handler.

Parsing and validation is done according to a specifier declared by
the driver's code. In the driver, all supported objects are declared.
These objects are separated to different object namepsaces. Dividing
objects to namespaces is done at initialization by using the higher
bits of the object ids. This initialization can mix objects declared
in different places to one parsing tree using in this ioctl interface.

For each object we list all supported methods. Similarly to objects,
methods are separated to method namespaces too. Namespacing is done
similarly to the objects case. This could be used in order to add
methods to an existing object.

Each method has a specific handler, which could be either a default
handler or a driver specific handler.
Along with the handler, a bunch of attributes are specified as well.
Similarly to objects and method, attributes are namespaced and hashed
by their ids at initialization too. All supported attributes are
subject to automatic fetching and validation. These attributes include
the command, response and the method's related objects' ids.

When these entities (objects, methods and attributes) are used, the
high bits of the entities ids are used in order to calculate the hash
bucket index. Then, these high bits are masked out in order to have a
zero based index. Since we use these high bits for both bucketing and
namespacing, we get a compact representation and O(1) array access.
This is mandatory for efficient dispatching.

Each attribute has a type (PTR_IN, PTR_OUT, IDR and FD) and a length.
Attributes could be validated through some attributes, like:
(*) Minimum size / Exact size
(*) Fops for FD
(*) Object type for IDR

If an IDR/fd attribute is specified, the kernel also states the object
type and the required access (NEW, WRITE, READ or DESTROY).
All uobject/fd management is done automatically by the infrastructure,
meaning - the infrastructure will fail concurrent commands that at
least one of them requires concurrent access (WRITE/DESTROY),
synchronize actions with device removals (dissociate context events)
and take care of reference counting (increase/decrease) for concurrent
actions invocation. The reference counts on the actual kernel objects
shall be handled by the handlers.

objects
+--------+
| |
| | methods +--------+
| | ns method method_spec +-----+ |len |
+--------+ +------+[d]+-------+ +----------------+[d]+------------+ |attr1+-> |type |
| object +> |method+-> | spec +-> + attr_buckets +-> |default_chain+--> +-----+ |idr_type|
+--------+ +------+ |handler| | | +------------+ |attr2| |access |
| | | | +-------+ +----------------+ |driver chain| +-----+ +--------+
| | | | +------------+
| | +------+
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
+--------+

[d] = Hash ids to groups using the high order bits

The right types table is also chosen by using the high bits from
the ids. Currently we have either default or driver specific groups.

Once validation and object fetching (or creation) completed, we call
the handler:
int (*handler)(struct ib_device *ib_dev, struct ib_uverbs_file *ufile,
struct uverbs_attr_bundle *ctx);

ctx bundles attributes of different namespaces. Each element there
is an array of attributes which corresponds to one namespaces of
attributes. For example, in the usually used case:

ctx core
+----------------------------+ +------------+
| core: +---> | valid |
+----------------------------+ | cmd_attr |
| driver: | +------------+
|----------------------------+--+ | valid |
| | cmd_attr |
| +------------+
| | valid |
| | obj_attr |
| +------------+
|
| drivers
| +------------+
+> | valid |
| cmd_attr |
+------------+
| valid |
| cmd_attr |
+------------+
| valid |
| obj_attr |
+------------+

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 to finalize objects in one transaction

The new ioctl based infrastructure either commits or rollbacks
all objects of the method as one transaction. In order to do
that, we introduce a notion of dealing with a collection of
objects that are related to a specific method.

This also requires adding a notion of a method and attribute.
A method contains a hash of attributes, where each bucket
contains several attributes. The attributes are hashed according
to their namespace which resides in the four upper bits of the id.

For example, an object could be a CQ, which has an action of CREATE_CQ.
This action has multiple attributes. For example, the CQ's new handle
and the comp_channel. Each layer in this hierarchy - objects, methods
and attributes is split into namespaces. The basic example for that is
one namespace representing the default entities and another one
representing the driver specific entities.

When declaring these methods and attributes, we actually declare
their specifications. When a method is executed, we actually
allocates some space to hold auxiliary information. This auxiliary
information contains meta-data about the required objects, such
as pointers to their type information, pointers to the uobjects
themselves (if exist), etc.
The specification, along with the auxiliary information we allocated
and filled is given to the finalize_objects function.

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 a generic way to execute an operation on a uobject

The ioctl infrastructure treats all user-objects in the same manner.
It gets objects ids from the user-space and by using the object type
and type attributes mentioned in the object specification, it executes
this required method. Passing an object id from the user-space as
an attribute is carried out in three stages. The first is carried out
before the actual handler and the last is carried out afterwards.

The different supported operations are read, write, destroy and create.
In the first stage, the former three actions just fetches the object
from the repository (by using its id) and locks it. The last action
allocates a new uobject. Afterwards, the second stage is carried out
when the handler itself carries out the required modification of the
object. The last stage is carried out after the handler finishes and
commits the result. The former two operations just unlock the object.
Destroy calls the "free object" operation, taking into account the
object's type and releases the uobject as well. Creation just adds the
new uobject to the repository, making the object visible to the
application.

In order to abstract these details from the ioctl infrastructure
layer, we add uverbs_get_uobject_from_context and
uverbs_finalize_object functions which corresponds to the first
and last stages respectively.

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