linux-kernel - [PATCH] ublk: consolidate UBLK_IO_FLAG_OWNED_BY

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Message-ID: <20250430213144.2625274-1-csander@purestorage.com>
Date: Wed, 30 Apr 2025 15:31:43 -0600
From: Caleb Sander Mateos <csander@...estorage.com>
To: Ming Lei <ming.lei@...hat.com>,
	Jens Axboe <axboe@...nel.dk>
Cc: Caleb Sander Mateos <csander@...estorage.com>,
	linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] ublk: consolidate UBLK_IO_FLAG_OWNED_BY_SRV checks

Every ublk I/O command except UBLK_IO_FETCH_REQ checks that the ublk_io
has UBLK_IO_FLAG_OWNED_BY_SRV set. Consolidate the separate checks into
a single one in __ublk_ch_uring_cmd(), analogous to those for
UBLK_IO_FLAG_ACTIVE and UBLK_IO_FLAG_NEED_GET_DATA.

Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
---
This is targeted at for-6.16/block, but depends on a recent commit that's only
on block-6.15.

 drivers/block/ublk_drv.c | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index f9032076bc06..692590fcd967 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -1951,20 +1951,16 @@ static void ublk_io_release(void *priv)
 static int ublk_register_io_buf(struct io_uring_cmd *cmd,
 				const struct ublk_queue *ubq, unsigned int tag,
 				unsigned int index, unsigned int issue_flags)
 {
 	struct ublk_device *ub = cmd->file->private_data;
-	const struct ublk_io *io = &ubq->ios[tag];
 	struct request *req;
 	int ret;
 
 	if (!ublk_support_zero_copy(ubq))
 		return -EINVAL;
 
-	if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
-		return -EINVAL;
-
 	req = __ublk_check_and_get_req(ub, ubq, tag, 0);
 	if (!req)
 		return -EINVAL;
 
 	ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,
@@ -1976,21 +1972,16 @@ static int ublk_register_io_buf(struct io_uring_cmd *cmd,
 
 	return 0;
 }
 
 static int ublk_unregister_io_buf(struct io_uring_cmd *cmd,
-				  const struct ublk_queue *ubq, unsigned int tag,
+				  const struct ublk_queue *ubq,
 				  unsigned int index, unsigned int issue_flags)
 {
-	const struct ublk_io *io = &ubq->ios[tag];
-
 	if (!ublk_support_zero_copy(ubq))
 		return -EINVAL;
 
-	if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
-		return -EINVAL;
-
 	return io_buffer_unregister_bvec(cmd, index, issue_flags);
 }
 
 static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
 		      struct ublk_io *io, __u64 buf_addr)
@@ -2072,10 +2063,15 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 	/* there is pending io cmd, something must be wrong */
 	if (io->flags & UBLK_IO_FLAG_ACTIVE) {
 		ret = -EBUSY;
 		goto out;
 	}
+ 
+	/* only UBLK_IO_FETCH_REQ is allowed if io is not OWNED_BY_SRV */
+	if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV) &&
+	    _IOC_NR(cmd_op) != UBLK_IO_FETCH_REQ)
+		goto out;
 
 	/*
 	 * ensure that the user issues UBLK_IO_NEED_GET_DATA
 	 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
 	 */
@@ -2090,22 +2086,18 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 	ret = -EINVAL;
 	switch (_IOC_NR(cmd_op)) {
 	case UBLK_IO_REGISTER_IO_BUF:
 		return ublk_register_io_buf(cmd, ubq, tag, ub_cmd->addr, issue_flags);
 	case UBLK_IO_UNREGISTER_IO_BUF:
-		return ublk_unregister_io_buf(cmd, ubq, tag, ub_cmd->addr, issue_flags);
+		return ublk_unregister_io_buf(cmd, ubq, ub_cmd->addr, issue_flags);
 	case UBLK_IO_FETCH_REQ:
 		ret = ublk_fetch(cmd, ubq, io, ub_cmd->addr);
 		if (ret)
 			goto out;
 		break;
 	case UBLK_IO_COMMIT_AND_FETCH_REQ:
 		req = blk_mq_tag_to_rq(ub->tag_set.tags[ub_cmd->q_id], tag);
-
-		if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
-			goto out;
-
 		if (ublk_need_map_io(ubq)) {
 			/*
 			 * COMMIT_AND_FETCH_REQ has to provide IO buffer if
 			 * NEED GET DATA is not enabled or it is Read IO.
 			 */
@@ -2123,12 +2115,10 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 
 		ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
 		ublk_commit_completion(ub, ub_cmd);
 		break;
 	case UBLK_IO_NEED_GET_DATA:
-		if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
-			goto out;
 		ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
 		req = blk_mq_tag_to_rq(ub->tag_set.tags[ub_cmd->q_id], tag);
 		ublk_dispatch_req(ubq, req, issue_flags);
 		return -EIOCBQUEUED;
 	default:
-- 
2.45.2