[Devel] [PATCH RHEL7 COMMIT] ub stat: commnad check helper introduced

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.8.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.8.4
------>
commit f9c9089662c033a8044d1fa9ff375ff0c2031b66
Author: Stanislav Kinsburskiy <skinsbursky at parallels.com>
Date:   Thu Oct 8 15:53:17 2015 +0400

    ub stat: commnad check helper introduced
    
    Signed-off-by: Stanislav Kinsburskiy <skinsbursky at parallels.com>
---
 kernel/bc/statd.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/kernel/bc/statd.c b/kernel/bc/statd.c
index b421ac1..db9f294 100644
--- a/kernel/bc/statd.c
+++ b/kernel/bc/statd.c
@@ -224,12 +224,29 @@ int ubstat_alloc_store(struct user_beancounter *ub)
 }
 EXPORT_SYMBOL(ubstat_alloc_store);
 
+static int ubstat_check_cmd(long cmd)
+{
+	switch (UBSTAT_CMD(cmd)) {
+		case UBSTAT_READ_ONE:
+			if (UBSTAT_PARMID(cmd) >= UB_RESOURCES)
+				break;
+		case UBSTAT_READ_ALL:
+		case UBSTAT_READ_FULL:
+			return 0;
+	}
+	return -EINVAL;
+}
+
 static int ubstat_get_stat(struct user_beancounter *ub, long cmd,
 		void __user *buf, long size)
 {
 	void *kbuf;
 	int retval;
 
+	retval = ubstat_check_cmd(cmd);
+	if (retval)
+		return retval;
+
 	kbuf = (void *)__get_free_page(GFP_KERNEL);
 	if (kbuf == NULL)
 		return -ENOMEM;
@@ -241,9 +258,6 @@ static int ubstat_get_stat(struct user_beancounter *ub, long cmd,
 	spin_lock(&ubs_notify_lock);
 	switch (UBSTAT_CMD(cmd)) {
 		case UBSTAT_READ_ONE:
-			retval = -EINVAL;
-			if (UBSTAT_PARMID(cmd) >= UB_RESOURCES)
-				break;
 			retval = ubstat_do_read_one(ub,
 					UBSTAT_PARMID(cmd), kbuf);
 			break;
@@ -255,6 +269,8 @@ static int ubstat_get_stat(struct user_beancounter *ub, long cmd,
 			break;
 		default:
 			retval = -EINVAL;
+			__WARN_printf("%s: we shouldn't get there\ncmd: %ld\n",
+					__func__, UBSTAT_CMD(cmd));
 	}
 	spin_unlock(&ubs_notify_lock);