io_provided_buffers_select() returns 0 to indicate success, but it should
be returning 1 to indicate that 1 vec was mapped. This causes peeking
to fail with classic provided buffers, and while that's not a use case
that anyone should use, it should still work correctly.

The end result is that no buffer will be selected, and hence a completion
with '0' as the result will be posted, without a buffer attached.

Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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>

Harden the buffer peeking a bit, by adding a sanity check for it having
a valid size. Outside of that, arg->max_len is a size_t, though it's
only ever set to a 32-bit value (as it's governed by MAX_RW_COUNT).
Bump our needed check to a size_t so we know it fits. Finally, cap the
calculated needed iov value to the PEEK_MAX_IMPORT, which is the
maximum number of segments that should be peeked.

Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There's a debug check in io_sq_thread_park() checking if it's the SQPOLL
thread itself calling park. KCSAN warns about this, as we should not be
reading sqd->thread outside of sqd->lock.

Just silence this with data_race(). The pointer isn't used for anything
but this debug check.

Reported-by: syzbot+2b946a3fd80caf971b21@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_napi_entry() has 2 calling sites. One of them is unlikely to find an
entry and if it does, the timeout should arguable not be updated.

The other io_napi_entry() calling site is overwriting the update made
by io_napi_entry() so the io_napi_entry() timeout value update has no or
little value and therefore is removed.

Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Link: https://lore.kernel.org/r/145b54ff179f87609e20dffaf5563c07cdbcad1a.1723423275.git.olivier@trillion01.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

doing so avoids the overhead of adding napi ids to all the rings that do
not enable napi.

if no id is added to napi_list because napi is disabled,
__io_napi_busy_loop() will not be called.

Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Fixes: b4ccc4dd1330 ("io_uring/napi: enable even with a timeout of 0")
Link: https://lore.kernel.org/r/bd989ccef5fda14f5fd9888faf4fefcf66bd0369.1723400131.git.olivier@trillion01.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If a send is issued marked with IOSQE_BUFFER_SELECT for selecting a
buffer, unless it's a bundle, it should not select multiple buffers.

Cc: stable@vger.kernel.org
Fixes: a05d1f625c7a ("io_uring/net: support bundles for send")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If the iovec inside the kmsg isn't already allocated AND one gets
expanded beyond the fixed size, then the request may not already have
been marked for cleanup. Ensure that it is.

Cc: stable@vger.kernel.org
Fixes: a05d1f625c7a ("io_uring/net: support bundles for send")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If the iovec inside the kmsg isn't already allocated AND one gets
expanded beyond the fixed size, then the request may not already have
been marked for cleanup. Ensure that it is.

Cc: stable@vger.kernel.org
Fixes: 2f9c9515bdfd ("io_uring/net: support bundles for recv")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

These lists are unused, remove them.

Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0a0ae3e955aed0f3e3d29882fb3d3cb575e0009b.1722294947.git.olivier@trillion01.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>