block: change blk_mq_add_to_batch() third argument type to bool

[ Upstream commit 9bce6b5f8987678b9c6c1fe433af6b5fe41feadc ]

Commit 1f47ed294a2b ("block: cleanup and fix batch completion adding
conditions") modified the evaluation criteria for the third argument,
'ioerror', in the blk_mq_add_to_batch() function. Initially, the
function had checked if 'ioerror' equals zero. Following the commit, it
started checking for negative error values, with the presumption that
such values, for instance -EIO, would be passed in.

However, blk_mq_add_to_batch() callers do not pass negative error
values. Instead, they pass status codes defined in various ways:

- NVMe PCI and Apple drivers pass NVMe status code
- virtio_blk driver passes the virtblk request header status byte
- null_blk driver passes blk_status_t

These codes are either zero or positive, therefore the revised check
fails to function as intended. Specifically, with the NVMe PCI driver,
this modification led to the failure of the blktests test case nvme/039.
In this test scenario, errors are artificially injected to the NVMe
driver, resulting in positive NVMe status codes passed to
blk_mq_add_to_batch(), which unexpectedly processes the failed I/O in a
batch. Hence the failure.

To correct the ioerror check within blk_mq_add_to_batch(), make all
callers to uniformly pass the argument as boolean. Modify the callers to
check their specific status codes and pass the boolean value 'is_error'.
Also describe the arguments of blK_mq_add_to_batch as kerneldoc.

Fixes: 1f47ed294a2b ("block: cleanup and fix batch completion adding conditions")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20250311104359.1767728-3-shinichiro.kawasaki@wdc.com
[axboe: fold in documentation update]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2 files changed, 5 insertions, 3 deletions

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index 0bca33dc48cc..05cd4c4f1ed6 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -599,7 +599,8 @@ static inline void apple_nvme_handle_cqe(struct apple_nvme_queue *q,
 	}
 
 	if (!nvme_try_complete_req(req, cqe->status, cqe->result) &&
-	    !blk_mq_add_to_batch(req, iob, nvme_req(req)->status,
+	    !blk_mq_add_to_batch(req, iob,
+				 nvme_req(req)->status != NVME_SC_SUCCESS,
 				 apple_nvme_complete_batch))
 		apple_nvme_complete_rq(req);
 }
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d2eeba15c73b..0b4ca8e8f9b4 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1131,8 +1131,9 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq,
 
 	trace_nvme_sq(req, cqe->sq_head, nvmeq->sq_tail);
 	if (!nvme_try_complete_req(req, cqe->status, cqe->result) &&
-	    !blk_mq_add_to_batch(req, iob, nvme_req(req)->status,
-					nvme_pci_complete_batch))
+	    !blk_mq_add_to_batch(req, iob,
+				 nvme_req(req)->status != NVME_SC_SUCCESS,
+				 nvme_pci_complete_batch))
 		nvme_pci_complete_rq(req);
 }