[PATCH] nvme-fc: fix the fc_appid_store return value

Christoph Hellwig
2022-08-06T08:32:38Z

"nvme-fc: fold t fc_update_appid into fc_appid_store" accidentally
changed the userspace interface for the appid attribute, because the code
that decrements "count" to remove a trailing '\n' in the parsing results
in the decremented value being incorrectly be returned from the sysfs
write. Fix this by keeping an orig_count variable for the full length
of the write.

Fixes: c814153c83a8 ("nvme-fc: fold t fc_update_appid into fc_appid_store")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Tested-by: Muneendra Kumar M <muneendra.kumar@broadcom.com>
---
drivers/nvme/host/fc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 8d14df8eeab84..127abaf9ba5d6 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -3880,6 +3880,7 @@ static int fc_parse_cgrpid(const char *buf, u64 *id)
static ssize_t fc_appid_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
+ size_t orig_count = count;
u64 cgrp_id;
int appid_len = 0;
int cgrpid_len = 0;
@@ -3904,7 +3905,7 @@ static ssize_t fc_appid_store(struct device *dev,
ret = blkcg_set_fc_appid(app_id, cgrp_id, sizeof(app_id));
if (ret < 0)
return ret;
- return count;
+ return orig_count;
}
static DEVICE_ATTR(appid_store, 0200, NULL, fc_appid_store);
#endif /* CONFIG_BLK_CGROUP_FC_APPID */
--
2.30.2