1 files changed, 32 insertions, 14 deletions

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index c9e4e5091da1..1f4a3f877262 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -19,10 +19,18 @@
 #include <linux/poll.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
+#include <linux/limits.h>
 #include <asm/uaccess.h>
 
 #include "sysfs.h"
 
+/* used in crash dumps to help with debugging */
+static char last_sysfs_file[PATH_MAX];
+void sysfs_printk_last_file(void)
+{
+        printk(KERN_EMERG "last sysfs file: %s\n", last_sysfs_file);
+}
+
 /*
  * There's one sysfs_buffer for each open file and one
  * sysfs_open_dirent for each sysfs_dirent with one or more open
@@ -328,6 +336,11 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
         struct sysfs_buffer *buffer;
         struct sysfs_ops *ops;
         int error = -EACCES;
+        char *p;
+
+        p = d_path(&file->f_path, last_sysfs_file, sizeof(last_sysfs_file));
+        if (p)
+                memmove(last_sysfs_file, p, strlen(p) + 1);
 
         /* need attr_sd for attr and ops, its parent for kobj */
         if (!sysfs_get_active_two(attr_sd))
@@ -440,7 +453,23 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
         return POLLERR|POLLPRI;
 }
 
-void sysfs_notify(struct kobject *k, char *dir, char *attr)
+void sysfs_notify_dirent(struct sysfs_dirent *sd)
+{
+        struct sysfs_open_dirent *od;
+
+        spin_lock(&sysfs_open_dirent_lock);
+
+        od = sd->s_attr.open;
+        if (od) {
+                atomic_inc(&od->event);
+                wake_up_interruptible(&od->poll);
+        }
+
+        spin_unlock(&sysfs_open_dirent_lock);
+}
+EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
+
+void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
 {
         struct sysfs_dirent *sd = k->sd;
 
@@ -450,19 +479,8 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr)
                 sd = sysfs_find_dirent(sd, dir);
         if (sd && attr)
                 sd = sysfs_find_dirent(sd, attr);
-        if (sd) {
-                struct sysfs_open_dirent *od;
-
-                spin_lock(&sysfs_open_dirent_lock);
-
-                od = sd->s_attr.open;
-                if (od) {
-                        atomic_inc(&od->event);
-                        wake_up_interruptible(&od->poll);
-                }
-
-                spin_unlock(&sysfs_open_dirent_lock);
-        }
+        if (sd)
+                sysfs_notify_dirent(sd);
 
         mutex_unlock(&sysfs_mutex);
 }