[PATCH 2/6] nvme-core: fix qid param blk_mq_alloc_request_hctx

Chaitanya Kulkarni
2022-06-07T01:17:30Z

Only caller of the __nvme_submit_sync_cmd() with qid value not equal to
NVME_QID_ANY is nvmf_connect_io_queues(), where qid value is alway set
to > 0.

[1] __nvme_submit_sync_cmd() callers with qid parameter from :-

Caller | qid parameter
------------------------------------------------------
* nvme_fc_connect_io_queues() |
nvmf_connect_io_queue() | qid > 0
* nvme_rdma_start_io_queues() |
nvme_rdma_start_queue() |
nvmf_connect_io_queues() | qid > 0
* nvme_tcp_start_io_queues() |
nvme_tcp_start_queue() |
nvmf_connect_io_queues() | qid > 0
* nvme_loop_connect_io_queues() |
nvmf_connect_io_queues() | qid > 0

When qid value of the function parameter __nvme_submit_sync_cmd() is > 0
from above callers, we use blk_mq_alloc_request_hctx(), where we pass
last parameter as 0 if qid functional parameter value is set to 0 with
conditional operators, see 1002 :-

991 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
992 union nvme_result *result, void *buffer, unsigned bufflen,
993 int qid, int at_head, blk_mq_req_flags_t flags)
994 {
995 struct request *req;
996 int ret;
997
998 if (qid == NVME_QID_ANY)
999 req = blk_mq_alloc_request(q, nvme_req_op(cmd), flags);
1000 else
1001 req = blk_mq_alloc_request_hctx(q, nvme_req_op(cmd), flags,
1002 qid ? qid - 1 : 0);
1003

But qid function parameter value of the __nvme_submit_sync_cmd() will
never be 0 from above caller list see [1], and all the other callers of
__nvme_submit_sync_cmd() use NVME_QID_ANY as qid value :-
1. nvme_submit_sync_cmd()
2. nvme_features()
3. nvme_sec_submit()
4. nvmf_reg_read32()
5. nvmf_reg_read64()
6. nvmf_ref_write32()
7. nvmf_connect_admin_queue()

Remove the conditional operator to pass the qid as 0 in the call to
blk_mq_alloc_requst_hctx().

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
---
drivers/nvme/host/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f46b0d37f45d..36943e245acf 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -999,7 +999,7 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
req = blk_mq_alloc_request(q, nvme_req_op(cmd), flags);
else
req = blk_mq_alloc_request_hctx(q, nvme_req_op(cmd), flags,
- qid ? qid - 1 : 0);
+ qid - 1);

if (IS_ERR(req))
return PTR_ERR(req);
--
2.29.0