From: Caleb Sander Mateos <csander@purestorage.com>
Date: Fri, 20 Jun 2025 15:09:58 +0000 (-0600)
Subject: ublk: handle UBLK_IO_FETCH_REQ earlier
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ee97736384beccc1f72116718af23e5f6de75210;p=thirdparty%2Fkernel%2Flinux.git

ublk: handle UBLK_IO_FETCH_REQ earlier

Check for UBLK_IO_FETCH_REQ early in __ublk_ch_uring_cmd() and skip the
rest of the checks in this case. This allows removing the checks for
NULL io->task and UBLK_IO_FLAG_OWNED_BY_SRV unset in io->flags, which
are only allowed for FETCH.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250620151008.3976463-5-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index cf550a56b19bb..c2f83036aacf1 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2215,8 +2215,18 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 		goto out;
 
 	io = &ubq->ios[tag];
+	/* UBLK_IO_FETCH_REQ can be handled on any task, which sets io->task */
+	if (unlikely(_IOC_NR(cmd_op) == UBLK_IO_FETCH_REQ)) {
+		ret = ublk_fetch(cmd, ubq, io, ub_cmd->addr);
+		if (ret)
+			goto out;
+
+		ublk_prep_cancel(cmd, issue_flags, ubq, tag);
+		return -EIOCBQUEUED;
+	}
+
 	task = READ_ONCE(io->task);
-	if (task && task != current)
+	if (task != current)
 		goto out;
 
 	/* there is pending io cmd, something must be wrong */
@@ -2225,9 +2235,7 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 		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)
+	if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
 		goto out;
 
 	/*
@@ -2243,11 +2251,6 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 		return ublk_register_io_buf(cmd, ubq, io, ub_cmd->addr, issue_flags);
 	case UBLK_IO_UNREGISTER_IO_BUF:
 		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:
 		ret = ublk_commit_and_fetch(ubq, io, cmd, ub_cmd, issue_flags);
 		if (ret)