[PATCH] nvme-multipath: Early exit if no path is available

[PATCH] nvme-multipath: Early exit if no path is available

[Daniel Wagner]

nvme_round_robin_path() should test if the return ns pointer is
valid. nvme_next_ns() will return a NULL pointer if there is no path
left.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/multipath.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index d578de0ce3aa..8837e9da1ccf 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -239,6 +239,8 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 	for (ns = nvme_next_ns(head, old);
 	     ns != old;
 	     ns = nvme_next_ns(head, ns)) {
+		if (!ns)
+			break;
 		if (nvme_path_is_disabled(ns))
 			continue;
 
-- 
2.29.2

[PATCH] nvme-multipath: Early exit if no path is available

[Daniel Wagner]

nvme_round_robin_path() should test if the return ns pointer is
valid. nvme_next_ns() will return a NULL pointer if there is no path
left.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/multipath.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index d578de0ce3aa..8837e9da1ccf 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -239,6 +239,8 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 	for (ns = nvme_next_ns(head, old);
 	     ns != old;
 	     ns = nvme_next_ns(head, ns)) {
+		if (!ns)
+			break;
 		if (nvme_path_is_disabled(ns))
 			continue;
 
-- 
2.29.2


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Re: [PATCH] nvme-multipath: Early exit if no path is available

[Christoph Hellwig]

On Fri, Jan 22, 2021 at 06:41:25PM +0100, Daniel Wagner wrote:
> nvme_round_robin_path() should test if the return ns pointer is
> valid. nvme_next_ns() will return a NULL pointer if there is no path
> left.

How can that happen once we're in the loop?

Re: [PATCH] nvme-multipath: Early exit if no path is available

[Christoph Hellwig]

On Fri, Jan 22, 2021 at 06:41:25PM +0100, Daniel Wagner wrote:
> nvme_round_robin_path() should test if the return ns pointer is
> valid. nvme_next_ns() will return a NULL pointer if there is no path
> left.

How can that happen once we're in the loop?

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Re: [PATCH] nvme-multipath: Early exit if no path is available

[Daniel Wagner]

On Fri, Jan 22, 2021 at 06:50:29PM +0100, Christoph Hellwig wrote:
> How can that happen once we're in the loop?

As far I can tell, it's the first nvme_next_ns() call which returns the
NULL pointer and this will pass the test 'ns != old'.

Re: [PATCH] nvme-multipath: Early exit if no path is available

[Daniel Wagner]

On Fri, Jan 22, 2021 at 06:50:29PM +0100, Christoph Hellwig wrote:
> How can that happen once we're in the loop?

As far I can tell, it's the first nvme_next_ns() call which returns the
NULL pointer and this will pass the test 'ns != old'.

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