ethtool: Update ethtool_rxnfc::rule_cnt on return from ETHTOOL_GRXCLSRLALL
A user-space process must use ETHTOOL_GRXCLSRLCNT to find the number
of classification rules, then allocate a buffer of the right size,
then use ETHTOOL_GRXCLSRLALL to fill the buffer. If some other
process inserts or deletes a rule between those two operations,
the user buffer might turn out to be the wrong size.
If it's too small, the return value will be -EMSGSIZE. But if it's
too large, there is no indication of this. Fix this by updating
the rule_cnt field on return.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 5d4a06a..45f00b6 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -496,9 +496,9 @@
*
* For %ETHTOOL_GRXCLSRLALL, @rule_cnt specifies the array size of the
* user buffer for @rule_locs on entry. On return, @data is the size
- * of the rule table and @rule_locs contains the locations of the
- * defined rules. Drivers must use the second parameter to get_rxnfc()
- * instead of @rule_locs.
+ * of the rule table, @rule_cnt is the number of defined rules, and
+ * @rule_locs contains the locations of the defined rules. Drivers
+ * must use the second parameter to get_rxnfc() instead of @rule_locs.
*
* For %ETHTOOL_SRXCLSRLINS, @fs specifies the rule to add or update.
* @fs.@location specifies the location to use and must not be ignored.