Re: [PATCH v3 3/3] nvme: handle connectivity loss in nvme_set_queue_count

From: Hannes Reinecke
Date: Fri Dec 20 2024 - 03:32:49 EST


On 12/17/24 15:01, Daniel Wagner wrote:
On Tue, Dec 17, 2024 at 10:45:45AM +0100, Hannes Reinecke wrote:
On 12/17/24 09:35, Daniel Wagner wrote:
On Fri, Nov 29, 2024 at 12:10:33PM +0100, Hannes Reinecke wrote:
+ /*
+ * It's either a kernel error or the host observed a connection
+ * lost. In either case it's not possible communicate with the
+ * controller and thus enter the error code path.
+ */
+ if (status < 0 || status == NVME_SC_HOST_PATH_ERROR)
return status;
/*

Hmm. Maybe checking for NVME_SC_DNR, too?

if no one complains I'll update the check to:

if (status < 0 || (status > 0 && (status & NVME_STATUS_DNR)) ||
status == NVME_SC_HOST_PATH_ERROR)
return status;

okay?

Which really cries out for a helper. But otherwise okay.

As far I remember, Christoph is not a big fan of single users of tiny
helper functions. Anyway, what about this:

+static bool nvme_num_queue_updated(status)
+{
+ /*
+ * It's either a kernel error or the host observed a connection
+ * lost. In either case it's not possible communicate with the
+ * controller and thus enter the error code path.
+ */
+
+ if (status < 0 || status & NVME_STATUS_DNR ||
+ status == NVME_SC_HOST_PATH_ERROR)
+ return false;
+
+ return true;
+}
+
int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count)
{
u32 q_count = (*count - 1) | ((*count - 1) << 16);
@@ -1701,13 +1716,8 @@ int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count)

status = nvme_set_features(ctrl, NVME_FEAT_NUM_QUEUES, q_count, NULL, 0,
&result);
- /*
- * It's either a kernel error or the host observed a connection
- * lost. In either case it's not possible communicate with the
- * controller and thus enter the error code path.
- */
- if (status < 0 || (status > 0 && (status & NVME_STATUS_DNR)) ||
- status == NVME_SC_HOST_PATH_ERROR)
+
+ if (!nvme_num_queue_updated(status))
return status;

/*

Naming is terrible. The helper does not check whether the number of queues updated, so why the name?

Better keep it inline, then.

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich