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

[Chaitanya Kulkarni <chaitanyak@nvidia.com>]

On 8/6/22 01:32, Christoph Hellwig wrote:
> "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.
> 
>

while we are at it perhaps we should consider fixing following ?

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 8d14df8eeab8..7ba35b059214 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -3886,10 +3886,10 @@ static ssize_t fc_appid_store(struct device *dev,
         char app_id[FC_APPID_LEN];
         int ret = 0;

-       if (buf[count-1] == '\n')
+       if (buf[count - 1] == '\n')
                 count--;

-       if ((count > (16+1+FC_APPID_LEN)) || (!strchr(buf, ':')))
+       if ((count > (16 + 1 + FC_APPID_LEN)) || (!strchr(buf, ':')))
                 return -EINVAL;

         cgrpid_len = fc_parse_cgrpid(buf, &cgrp_id);
@@ -3900,7 +3900,7 @@ static ssize_t fc_appid_store(struct device *dev,
                 return -EINVAL;

         memset(app_id, 0x0, sizeof(app_id));
-       memcpy(app_id, &buf[cgrpid_len+1], appid_len);
+       memcpy(app_id, &buf[cgrpid_len + 1], appid_len);
         ret = blkcg_set_fc_appid(app_id, cgrp_id, sizeof(app_id));
         if (ret < 0)
                 return ret;

or lmk if I should send a different patch..

-ck