sockets: Decode kernel dev_t into stat's one

Unix diag and stat report dev_t-s in different formats. Cast one to
another when comparing in unix dumping.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

include/util.h

@@ -264,4 +264,25 @@ FILE *fopen_proc(int pid_dir_fd, char *fmt, ...);
 #define pr_img_head(type, ...)	pr_info("\n"#type __VA_ARGS__ "\n----------------\n")
 #define pr_img_tail(type)	pr_info("----------------\n")
 
+#define KDEV_MINORBITS	20
+#define KDEV_MINORMASK	((1UL << KDEV_MINORBITS) - 1)
+
+static inline u32 kdev_major(u32 kdev)
+{
+	return kdev >> KDEV_MINORBITS;
+}
+
+static inline u32 kdev_minor(u32 kdev)
+{
+	return kdev & KDEV_MINORMASK;
+}
+
+static inline dev_t kdev_to_odev(u32 kdev)
+{
+	/*
+	 * New kernels envcode devices in a new form
+	 */
+	return (kdev_major(kdev) << 8) | kdev_minor(kdev);
+}
+
 #endif /* UTIL_H_ */

sockets.c

@@ -466,7 +466,10 @@ static int unix_collect_one(struct unix_diag_msg *m, struct rtattr **tb)
 			}
 
 			if ((st.st_ino != uv->udiag_vfs_ino) ||
-			    (st.st_dev != uv->udiag_vfs_dev)) {
+			    (st.st_dev != kdev_to_odev(uv->udiag_vfs_dev))) {
+				pr_info("unix: Dropping path for unlinked bound sk %x.%x real %x.%x\n",
+						(int)st.st_dev, (int)st.st_ino,
+						(int)uv->udiag_vfs_dev, (int)uv->udiag_vfs_ino);
 				/*
 				 * When a listen socket is bound to
 				 * unlinked file, we just drop his name,