This patch removes some "cold" fields from `struct io_issue_def`.

The plan is to keep only highly used fields into `struct io_issue_def`, so,
it may be hot in the cache. The hot fields are basically all the bitfields
and the callback functions for .issue and .prep.

The other less frequently used fields are now located in a secondary and
cold struct, called `io_cold_def`.

This is the size for the structs:

Before: io_issue_def = 56 bytes
After: io_issue_def = 24 bytes; io_cold_def = 40 bytes

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20230112144411.2624698-2-leitao@debian.org


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

The current io_op_def struct is becoming huge and the name is a bit
generic.

The goal of this patch is to rename this struct to `io_issue_def`. This
struct will contain the hot functions associated with the issue code
path.

For now, this patch only renames the structure, and an upcoming patch
will break up the structure in two, moving the non-issue fields to a
secondary struct.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20230112144411.2624698-1-leitao@debian.org


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

We should not be messing with req->file outside of core paths. Clearing
it makes msg_ring non reentrant, i.e. luckily io_msg_send_fd() fails the
request on failed io_double_lock_ctx() but clearly was originally
intended to do retries instead.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e5ac9edadb574fe33f6d727cb8f14ce68262a684.1670384893.git.asml.silence@gmail.com


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

Sometimes we have to do a little bit of a fixup on a request failuer in
io_req_complete_failed(). Add a callback in opdef for that.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b734cff4e67cb30cca976b9face321023f37549a.1663668091.git.asml.silence@gmail.com


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

There are opcodes that need ->async_data only in some cases and
allocation it unconditionally may hurt performance. Add an option to
opdef to make move the allocation part from the core io_uring to opcode
specific code.
Note, we can't just set opdef->async_size to zero because there are
other helpers that rely on it, e.g. io_alloc_async_data().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9dc62be9e88dd0ed63c48365340e8922d2498293.1661342812.git.asml.silence@gmail.com


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

We already have the declarations in opdef.h, move the rest into its own
file rather than in the main io_uring.c file.

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

Add a io_poll_issue() rather than export the general task_work locking
and io_issue_sqe(), and put the io_op_defs definition and structure into
a separate header file so that poll can use it.

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