[PATCH] scsi: scsi_devinfo: return an error when the proc write fails

[shao.mingyin]

From: Shao Mingyin <shao.mingyin@xxxxxxxxxx>

proc_scsi_devinfo_write() calls scsi_dev_info_list_add_str() but ignores
its return value, so a write to /proc/scsi/device_info always reports
success, even when the string is malformed and no entry was added.  Users
and scripts then believe that the quirk is in effect.

scsi_init_devinfo() already checks the return value of the same function
and fails the initialization.  Return the parser error, but keep returning
the number of bytes written on success: a proc write handler that returns
zero for a non-empty write would look like a short write to the caller.

Signed-off-by: Shao Mingyin <shao.mingyin@xxxxxxxxxx>
---
diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index cfc259fd0141..b1f3bcd739b4 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -688,6 +688,7 @@ static ssize_t proc_scsi_devinfo_write(struct file *file,
 {
 	char *buffer;
 	ssize_t err = length;
+	int ret;

 	if (!buf || length>PAGE_SIZE)
 		return -EINVAL;
@@ -706,7 +707,9 @@ static ssize_t proc_scsi_devinfo_write(struct file *file,
 		goto out;
 	}

-	scsi_dev_info_list_add_str(buffer);
+	ret = scsi_dev_info_list_add_str(buffer);
+	if (ret)
+		err = ret;

 out:
 	kfree(buffer);