Commit c9d066eb authored by Caleb Sander Mateos's avatar Caleb Sander Mateos Committed by Jens Axboe
Browse files

ublk: remove ubq checks from ublk_{get,put}_req_ref() 



ublk_get_req_ref() and ublk_put_req_ref() currently call
ublk_need_req_ref(ubq) to check whether the ublk device features require
reference counting of its requests. However, all callers already know
that reference counting is required:
- __ublk_check_and_get_req() is only called from
  ublk_check_and_get_req() if user copy is enabled, and from
  ublk_register_io_buf() if zero copy is enabled
- ublk_io_release() is only called for requests registered by
  ublk_register_io_buf(), which requires zero copy
- ublk_ch_read_iter() and ublk_ch_write_iter() only call
  ublk_put_req_ref() if ublk_check_and_get_req() succeeded, which
  requires user copy to be enabled

So drop the ublk_need_req_ref() check and the ubq argument in
ublk_get_req_ref() and ublk_put_req_ref().

Signed-off-by: default avatarCaleb Sander Mateos <csander@purestorage.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250620151008.3976463-14-csander@purestorage.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1ceeedb5

drivers/block/ublk_drv.c

+11 −24
Original line number Diff line number Diff line
@@ -699,24 +699,15 @@ static inline void ublk_init_req_ref(const struct ublk_queue *ubq, 
		refcount_set(&io->ref, UBLK_REFCOUNT_INIT);

}



static inline bool ublk_get_req_ref(const struct ublk_queue *ubq,

		struct ublk_io *io)

static inline bool ublk_get_req_ref(struct ublk_io *io)

{

	if (ublk_need_req_ref(ubq))

	return refcount_inc_not_zero(&io->ref);



	return true;

}



static inline void ublk_put_req_ref(const struct ublk_queue *ubq,

		struct ublk_io *io, struct request *req)

static inline void ublk_put_req_ref(struct ublk_io *io, struct request *req)

{

	if (ublk_need_req_ref(ubq)) {

	if (refcount_dec_and_test(&io->ref))

		__ublk_complete_rq(req);

	} else {

		__ublk_complete_rq(req);

	}

}



static inline void ublk_sub_req_ref(struct ublk_io *io, struct request *req)
@@ -2037,7 +2028,7 @@ static void ublk_io_release(void *priv) 
	if (current == io->task && io->task_registered_buffers)

		io->task_registered_buffers--;

	else

		ublk_put_req_ref(ubq, io, rq);

		ublk_put_req_ref(io, rq);

}



static int ublk_register_io_buf(struct io_uring_cmd *cmd,
@@ -2059,7 +2050,7 @@ static int ublk_register_io_buf(struct io_uring_cmd *cmd, 
	ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,

				      issue_flags);

	if (ret) {

		ublk_put_req_ref(ubq, io, req);

		ublk_put_req_ref(io, req);

		return ret;

	}
@@ -2366,7 +2357,7 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub, 
	if (!req)

		return NULL;



	if (!ublk_get_req_ref(ubq, io))

	if (!ublk_get_req_ref(io))

		return NULL;



	if (unlikely(!blk_mq_request_started(req) || req->tag != tag))
@@ -2380,7 +2371,7 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub, 


	return req;

fail_put:

	ublk_put_req_ref(ubq, io, req);

	ublk_put_req_ref(io, req);

	return NULL;

}
@@ -2496,13 +2487,12 @@ static struct request *ublk_check_and_get_req(struct kiocb *iocb, 
	*off = buf_off;

	return req;

fail:

	ublk_put_req_ref(ubq, *io, req);

	ublk_put_req_ref(*io, req);

	return ERR_PTR(-EACCES);

}



static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to)

{

	struct ublk_queue *ubq;

	struct request *req;

	struct ublk_io *io;

	size_t buf_off;
@@ -2513,15 +2503,13 @@ static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to) 
		return PTR_ERR(req);



	ret = ublk_copy_user_pages(req, buf_off, to, ITER_DEST);

	ubq = req->mq_hctx->driver_data;

	ublk_put_req_ref(ubq, io, req);

	ublk_put_req_ref(io, req);



	return ret;

}



static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from)

{

	struct ublk_queue *ubq;

	struct request *req;

	struct ublk_io *io;

	size_t buf_off;
@@ -2532,8 +2520,7 @@ static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from) 
		return PTR_ERR(req);



	ret = ublk_copy_user_pages(req, buf_off, from, ITER_SOURCE);

	ubq = req->mq_hctx->driver_data;

	ublk_put_req_ref(ubq, io, req);

	ublk_put_req_ref(io, req);



	return ret;

}