NTB/msi: Use struct_size() helper in devm_kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/ntb/msi.c:46:23: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

NTB/msi: Fix ntbm_msi_request_threaded_irq() kernel-doc comment

Add the description of @msi_desc and change the @devname to @name
in ntbm_msi_request_threaded_irq() kernel-doc comment to remove
some warnings found by running scripts/kernel-doc, which is caused
by using 'make W=1'.
drivers/ntb/msi.c:285: warning: Function parameter or member 'name' not
described in 'ntbm_msi_request_threaded_irq'
drivers/ntb/msi.c:285: warning: Function parameter or member 'msi_desc'
not described in 'ntbm_msi_request_threaded_irq'
drivers/ntb/msi.c:285: warning: Excess function parameter 'devname'
description in 'ntbm_msi_request_threaded_irq'

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

NTB/msi: Convert to msi_on_each_desc()

Replace the about to vanish iterators, make use of the filtering and take
the descriptor lock around the iteration.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211206210748.683004012@linutronix.de

NTB/msi: Use irq_has_action()

Use the proper core function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Link: https://lore.kernel.org/r/20201210194044.255887860@linutronix.de

NTB/msi: remove incorrect MODULE defines

msi.c is not a module on its own right and should not have the
MODULE_[LICENSE|VERSION|AUTHOR|DESCRIPTION] definitions.

This caused a regression noticed by lkp with the following back
trace:

WARNING: CPU: 0 PID: 1 at kernel/params.c:861 param_sysfs_init+0xb1/0x20a
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc1-00018-g26b3a37b928457 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
RIP: 0010:param_sysfs_init+0xb1/0x20a
Code: 24 38 e8 ec 17 2e fd 49 8b 7c 24 38 e8 76 fe ff ff 48 85 c0 48 89 c5 74 25 31 d2 4c 89 e6 48 89 c7 e8 6d 6f 3c fd 85 c0 74 02 <0f> 0b 48 89 ef 31 f6 e8 5d 70 a7 fe 48 89 ef e8 95 52 a7 fe 48 83
RSP: 0000:ffff88806b0ffe30 EFLAGS: 00010282
RAX: 00000000ffffffef RBX: ffffffff83774220 RCX: ffff88806a85e880
RDX: 00000000ffffffef RSI: ffff88806b000400 RDI: ffff88806a8608c0
RBP: ffff88806b392000 R08: ffffed100d61ff59 R09: ffffed100d61ff59
R10: 0000000000000001 R11: ffffed100d61ff58 R12: ffffffff83974bc0
R13: 0000000000000004 R14: 0000000000000028 R15: 00000000000003b9
FS: 0000000000000000(0000) GS:ffff88806b800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000380e000 CR4: 00000000000406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
? file_caps_disable+0x10/0x10
? locate_module_kobject+0xf2/0xf2
do_one_initcall+0x47/0x1f0
kernel_init_freeable+0x1b1/0x243
? rest_init+0xd0/0xd0
kernel_init+0xa/0x130
? calculate_sigpending+0x63/0x80
? rest_init+0xd0/0xd0
ret_from_fork+0x1f/0x30
---[ end trace 78201497ae74cc91 ]---

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 26b3a37b9284 ("NTB: Introduce MSI library")
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

NTB: Introduce MSI library

The NTB MSI library allows passing MSI interrupts across a memory
window. This offers similar functionality to doorbells or messages
except will often have much better latency and the client can
potentially use significantly more remote interrupts than typical hardware
provides for doorbells. (Which can be important in high-multiport
setups.)

The library utilizes one memory window per peer and uses the highest
index memory windows. Before any ntb_msi function may be used, the user
must call ntb_msi_init(). It may then setup and tear down the memory
windows when the link state changes using ntb_msi_setup_mws() and
ntb_msi_clear_mws().

The peer which receives the interrupt must call ntb_msim_request_irq()
to assign the interrupt handler (this function is functionally
similar to devm_request_irq()) and the returned descriptor must be
transferred to the peer which can use it to trigger the interrupt.
The triggering peer, once having received the descriptor, can
trigger the interrupt by calling ntb_msi_peer_trigger().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>