Commit 9e4c6c1a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'io_uring-6.12-20241011' of git://git.kernel.dk/linux 

Pull io_uring fixes from Jens Axboe:

 - Explicitly have a mshot_finished condition for IORING_OP_RECV in
   multishot mode, similarly to what IORING_OP_RECVMSG has. This doesn't
   fix a bug right now, but it makes it harder to actually have a bug
   here if a request takes multiple iterations to finish.

 - Fix handling of retry of read/write of !FMODE_NOWAIT files. If they
   are pollable, that's all we need.

* tag 'io_uring-6.12-20241011' of git://git.kernel.dk/linux:
  io_uring/rw: allow pollable non-blocking attempts for !FMODE_NOWAIT
  io_uring/rw: fix cflags posting for single issue multishot read
parents e643edac f7c91343

io_uring/rw.c

+24 −20
Original line number Diff line number Diff line
@@ -31,9 +31,19 @@ struct io_rw { 
	rwf_t				flags;

};



static inline bool io_file_supports_nowait(struct io_kiocb *req)

static bool io_file_supports_nowait(struct io_kiocb *req, __poll_t mask)

{

	return req->flags & REQ_F_SUPPORT_NOWAIT;

	/* If FMODE_NOWAIT is set for a file, we're golden */

	if (req->flags & REQ_F_SUPPORT_NOWAIT)

		return true;

	/* No FMODE_NOWAIT, if we can poll, check the status */

	if (io_file_can_poll(req)) {

		struct poll_table_struct pt = { ._key = mask };



		return vfs_poll(req->file, &pt) & mask;

	}

	/* No FMODE_NOWAIT support, and file isn't pollable. Tough luck. */

	return false;

}



#ifdef CONFIG_COMPAT
@@ -796,8 +806,8 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode, int rw_type) 
	 * supports async. Otherwise it's impossible to use O_NONBLOCK files

	 * reliably. If not, or it IOCB_NOWAIT is set, don't retry.

	 */

	if ((kiocb->ki_flags & IOCB_NOWAIT) ||

	    ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))

	if (kiocb->ki_flags & IOCB_NOWAIT ||

	    ((file->f_flags & O_NONBLOCK && (req->flags & REQ_F_SUPPORT_NOWAIT))))

		req->flags |= REQ_F_NOWAIT;



	if (ctx->flags & IORING_SETUP_IOPOLL) {
@@ -838,7 +848,7 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags) 


	if (force_nonblock) {

		/* If the file doesn't support async, just async punt */

		if (unlikely(!io_file_supports_nowait(req)))

		if (unlikely(!io_file_supports_nowait(req, EPOLLIN)))

			return -EAGAIN;

		kiocb->ki_flags |= IOCB_NOWAIT;

	} else {
@@ -951,13 +961,6 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags) 


	ret = __io_read(req, issue_flags);



	/*

	 * If the file doesn't support proper NOWAIT, then disable multishot

	 * and stay in single shot mode.

	 */

	if (!io_file_supports_nowait(req))

		req->flags &= ~REQ_F_APOLL_MULTISHOT;



	/*

	 * If we get -EAGAIN, recycle our buffer and just let normal poll

	 * handling arm it.
@@ -972,14 +975,15 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags) 
		if (issue_flags & IO_URING_F_MULTISHOT)

			return IOU_ISSUE_SKIP_COMPLETE;

		return -EAGAIN;

	}



	/*

	 * Any successful return value will keep the multishot read armed.

	 */

	if (ret > 0 && req->flags & REQ_F_APOLL_MULTISHOT) {

	} else if (ret <= 0) {

		io_kbuf_recycle(req, issue_flags);

		if (ret < 0)

			req_set_fail(req);

	} else {

		/*

		 * Put our buffer and post a CQE. If we fail to post a CQE, then

		 * Any successful return value will keep the multishot read

		 * armed, if it's still set. Put our buffer and post a CQE. If

		 * we fail to post a CQE, or multishot is no longer set, then

		 * jump to the termination path. This request is then done.

		 */

		cflags = io_put_kbuf(req, ret, issue_flags);
@@ -1026,7 +1030,7 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) 


	if (force_nonblock) {

		/* If the file doesn't support async, just async punt */

		if (unlikely(!io_file_supports_nowait(req)))

		if (unlikely(!io_file_supports_nowait(req, EPOLLOUT)))

			goto ret_eagain;



		/* Check if we can support NOWAIT. */