ipc: clamp with min()

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 22 deletions

diff --git a/ipc/msgutil.c b/ipc/msgutil.c
index 5df8e4bf1db0..98b1c2b476cc 100644
--- a/ipc/msgutil.c
+++ b/ipc/msgutil.c
@@ -41,8 +41,8 @@ struct msg_msgseg {
         /* the next part of the message follows immediately */
 };
 
-#define DATALEN_MSG     (PAGE_SIZE-sizeof(struct msg_msg))
-#define DATALEN_SEG     (PAGE_SIZE-sizeof(struct msg_msgseg))
+#define DATALEN_MSG     (int)(PAGE_SIZE-sizeof(struct msg_msg))
+#define DATALEN_SEG     (int)(PAGE_SIZE-sizeof(struct msg_msgseg))
 
 struct msg_msg *load_msg(const void __user *src, int len)
 {
@@ -51,10 +51,7 @@ struct msg_msg *load_msg(const void __user *src, int len)
         int err;
         int alen;
 
-        alen = len;
-        if (alen > DATALEN_MSG)
-                alen = DATALEN_MSG;
-
+        alen = min(len, DATALEN_MSG);
         msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
         if (msg == NULL)
                 return ERR_PTR(-ENOMEM);
@@ -72,9 +69,7 @@ struct msg_msg *load_msg(const void __user *src, int len)
         pseg = &msg->next;
         while (len > 0) {
                 struct msg_msgseg *seg;
-                alen = len;
-                if (alen > DATALEN_SEG)
-                        alen = DATALEN_SEG;
+                alen = min(len, DATALEN_SEG);
                 seg = kmalloc(sizeof(*seg) + alen,
                                                  GFP_KERNEL);
                 if (seg == NULL) {
@@ -113,19 +108,14 @@ struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
         if (src->m_ts > dst->m_ts)
                 return ERR_PTR(-EINVAL);
 
-        alen = len;
-        if (alen > DATALEN_MSG)
-                alen = DATALEN_MSG;
-
+        alen = min(len, DATALEN_MSG);
         memcpy(dst + 1, src + 1, alen);
 
         len -= alen;
         dst_pseg = dst->next;
         src_pseg = src->next;
         while (len > 0) {
-                alen = len;
-                if (alen > DATALEN_SEG)
-                        alen = DATALEN_SEG;
+                alen = min(len, DATALEN_SEG);
                 memcpy(dst_pseg + 1, src_pseg + 1, alen);
                 dst_pseg = dst_pseg->next;
                 len -= alen;
@@ -148,9 +138,7 @@ int store_msg(void __user *dest, struct msg_msg *msg, int len)
         int alen;
         struct msg_msgseg *seg;
 
-        alen = len;
-        if (alen > DATALEN_MSG)
-                alen = DATALEN_MSG;
+        alen = min(len, DATALEN_MSG);
         if (copy_to_user(dest, msg + 1, alen))
                 return -1;
 
@@ -158,9 +146,7 @@ int store_msg(void __user *dest, struct msg_msg *msg, int len)
         dest = ((char __user *)dest) + alen;
         seg = msg->next;
         while (len > 0) {
-                alen = len;
-                if (alen > DATALEN_SEG)
-                        alen = DATALEN_SEG;
+                alen = min(len, DATALEN_SEG);
                 if (copy_to_user(dest, seg + 1, alen))
                         return -1;
                 len -= alen;