For buffer registration (or updates), a userspace iovec is copied in
and updated. If the application is within a compat syscall, then the
iovec type is compat_iovec rather than iovec. However, the type used
in __io_sqe_buffers_update() and io_sqe_buffers_register() is always
struct iovec, and hence the source is incremented by the size of a
non-compat iovec in the loop. This misses every other iovec in the
source, and will run into garbage half way through the copies and
return -EFAULT to the application.

Maintain the source address separately and assign to our user vec
pointer, so that copies always happen from the right source address.

While in there, correct a bad placement of __user which triggered
the following sparse warning prior to this fix:

io_uring/rsrc.c:981:33: warning: cast removes address space '__user' of expression
io_uring/rsrc.c:981:30: warning: incorrect type in assignment (different address spaces)
io_uring/rsrc.c:981:30:    expected struct iovec const [noderef] __user *uvec
io_uring/rsrc.c:981:30:    got struct iovec *[noderef] __user

Fixes: f4eaf8eda89e ("io_uring/rsrc: Drop io_copy_iov in favor of iovec API")
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull io_uring updates from Jens Axboe:
 "Here are the io_uring updates queued up for 6.11.

  Nothing major this time around, various minor improvements and
  cleanups/fixes. This contains:

   - Add bind/listen opcodes. Main motivation is to support direct
     descriptors, to avoid needing a regular fd just for doing these two
     operations (Gabriel)

   - Probe fixes (Gabriel)

   - Treat io-wq work flags as atomics. Not fixing a real issue, but may
     as well and it silences a KCSAN warning (me)

   - Cleanup of rsrc __set_current_state() usage (me)

   - Add 64-bit for {m,f}advise operations (me)

   - Improve performance of data ring messages (me)

   - Fix for ring message overflow posting (Pavel)

   - Fix for freezer interaction with TWA_NOTIFY_SIGNAL. Not strictly an
     io_uring thing, but since TWA_NOTIFY_SIGNAL was originally added
     for faster task_work signaling for io_uring, bundling it with this
     pull (Pavel)

   - Add Pavel as a co-maintainer

   - Various cleanups (me, Thorsten)"

* tag 'for-6.11/io_uring-20240714' of git://git.kernel.dk/linux: (28 commits)
  io_uring/net: check socket is valid in io_bind()/io_listen()
  kernel: rerun task_work while freezing in get_signal()
  io_uring/io-wq: limit retrying worker initialisation
  io_uring/napi: Remove unnecessary s64 cast
  io_uring/net: cleanup io_recv_finish() bundle handling
  io_uring/msg_ring: fix overflow posting
  MAINTAINERS: change Pavel Begunkov from io_uring reviewer to maintainer
  io_uring/msg_ring: use kmem_cache_free() to free request
  io_uring/msg_ring: check for dead submitter task
  io_uring/msg_ring: add an alloc cache for io_kiocb entries
  io_uring/msg_ring: improve handling of target CQE posting
  io_uring: add io_add_aux_cqe() helper
  io_uring: add remote task_work execution helper
  io_uring/msg_ring: tighten requirement for remote posting
  io_uring: Allocate only necessary memory in io_probe
  io_uring: Fix probe of disabled operations
  io_uring: Introduce IORING_OP_LISTEN
  io_uring: Introduce IORING_OP_BIND
  net: Split a __sys_listen helper for io_uring
  net: Split a __sys_bind helper for io_uring
  ...

In io_import_fixed when advancing the iter within the first bvec, the
iter->nr_segs is set to bvec->bv_len. nr_segs should be the number of
bvecs, plus we don't need to adjust it here, so just remove it.

Fixes: b000ae0ec2d7 ("io_uring/rsrc: optimise single entry advance")
Signed-off-by: Chenliang Li <cliang01.li@samsung.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20240619063819.2445-1-cliang01.li@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We're guaranteed to be in a TASK_RUNNING state post schedule, so we
never need to set the state after that. While in there, remove the
other __set_current_state() as well, and just call finish_wait()
when we now we're going to break anyway. This is easier to grok than
manual __set_current_state() calls.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Instead of open coding an io_uring function to copy iovs from userspace,
rely on the existing iovec_from_user function.  While there, avoid
repeatedly zeroing the iov in the !arg case for io_sqe_buffer_register.

tested with liburing testsuite.

Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20240523214535.31890-1-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There is a report of io_rsrc_ref_quiesce() locking a mutex while not
TASK_RUNNING, which is due to forgetting restoring the state back after
io_run_task_work_sig() and attempts to break out of the waiting loop.

do not call blocking ops when !TASK_RUNNING; state=1 set at
[<ffffffff815d2494>] prepare_to_wait+0xa4/0x380
kernel/sched/wait.c:237
WARNING: CPU: 2 PID: 397056 at kernel/sched/core.c:10099
__might_sleep+0x114/0x160 kernel/sched/core.c:10099
RIP: 0010:__might_sleep+0x114/0x160 kernel/sched/core.c:10099
Call Trace:
 <TASK>
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0xb4/0x940 kernel/locking/mutex.c:752
 io_rsrc_ref_quiesce+0x590/0x940 io_uring/rsrc.c:253
 io_sqe_buffers_unregister+0xa2/0x340 io_uring/rsrc.c:799
 __io_uring_register io_uring/register.c:424 [inline]
 __do_sys_io_uring_register+0x5b9/0x2400 io_uring/register.c:613
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd8/0x270 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

Reported-by: Li Shi <sl1589472800@gmail.com>
Fixes: 4ea15b56f0810 ("io_uring/rsrc: use wq for quiescing")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/77966bc104e25b0534995d5dbb152332bc8f31c0.1718196953.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Move the related code from io_uring.c into memmap.c. No functional
changes in this patch, just cleaning it up a bit now that the full
transition is done.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Move it into io_uring.c where it belongs, and use it in there as well
rather than have two implementations of this.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently lists are being used to manage this, but best practice is
usually to have these in an array instead as that it cheaper to manage.

Outside of that detail, games are also played with KASAN as the list
is inside the cached entry itself.

Finally, all users of this need a struct io_cache_entry embedded in
their struct, which is union'ized with something else in there that
isn't used across the free -> realloc cycle.

Get rid of all of that, and simply have it be an array. This will not
change the memory used, as we're just trading an 8-byte member entry
for the per-elem array size.

This reduces the overhead of the recycled allocations, and it reduces
the amount of code code needed to support recycling to about half of
what it currently is.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

This is dead code after we dropped support for passing io_uring fds
over SCM_RIGHTS, get rid of it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>