[PATCH] sem2mutex: eventpoll

Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/eventpoll.c

@@ -34,6 +34,7 @@
 #include <linux/eventpoll.h>
 #include <linux/mount.h>
 #include <linux/bitops.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <asm/io.h>
@@ -46,7 +47,7 @@
  * LOCKING:
  * There are three level of locking required by epoll :
  *
- * 1) epsem (semaphore)
+ * 1) epmutex (mutex)
  * 2) ep->sem (rw_semaphore)
  * 3) ep->lock (rw_lock)
  *
@@ -67,9 +68,9 @@
  * if a file has been pushed inside an epoll set and it is then
  * close()d without a previous call toepoll_ctl(EPOLL_CTL_DEL).
  * It is possible to drop the "ep->sem" and to use the global
- * semaphore "epsem" (together with "ep->lock") to have it working,
+ * semaphore "epmutex" (together with "ep->lock") to have it working,
  * but having "ep->sem" will make the interface more scalable.
- * Events that require holding "epsem" are very rare, while for
+ * Events that require holding "epmutex" are very rare, while for
  * normal operations the epoll private "ep->sem" will guarantee
  * a greater scalability.
  */
@@ -274,7 +275,7 @@ static struct super_block *eventpollfs_get_sb(struct file_system_type *fs_type,
 /*
  * This semaphore is used to serialize ep_free() and eventpoll_release_file().
  */
-static struct semaphore epsem;
+static struct mutex epmutex;
 
 /* Safe wake up implementation */
 static struct poll_safewake psw;
@@ -477,10 +478,10 @@ void eventpoll_release_file(struct file *file)
 	 * cleanup path, and this means that noone is using this file anymore.
 	 * The only hit might come from ep_free() but by holding the semaphore
 	 * will correctly serialize the operation. We do need to acquire
-	 * "ep->sem" after "epsem" because ep_remove() requires it when called
+	 * "ep->sem" after "epmutex" because ep_remove() requires it when called
 	 * from anywhere but ep_free().
 	 */
-	down(&epsem);
+	mutex_lock(&epmutex);
 
 	while (!list_empty(lsthead)) {
 		epi = list_entry(lsthead->next, struct epitem, fllink);
@@ -492,7 +493,7 @@ void eventpoll_release_file(struct file *file)
 		up_write(&ep->sem);
 	}
 
-	up(&epsem);
+	mutex_unlock(&epmutex);
 }
 
 
@@ -819,9 +820,9 @@ static void ep_free(struct eventpoll *ep)
 	 * We do not need to hold "ep->sem" here because the epoll file
 	 * is on the way to be removed and no one has references to it
 	 * anymore. The only hit might come from eventpoll_release_file() but
-	 * holding "epsem" is sufficent here.
+	 * holding "epmutex" is sufficent here.
 	 */
-	down(&epsem);
+	mutex_lock(&epmutex);
 
 	/*
 	 * Walks through the whole tree by unregistering poll callbacks.
@@ -843,7 +844,7 @@ static void ep_free(struct eventpoll *ep)
 		ep_remove(ep, epi);
 	}
 
-	up(&epsem);
+	mutex_unlock(&epmutex);
 }
 
 
@@ -1615,7 +1616,7 @@ static int __init eventpoll_init(void)
 {
 	int error;
 
-	init_MUTEX(&epsem);
+	mutex_init(&epmutex);
 
 	/* Initialize the structure used to perform safe poll wait head wake ups */
 	ep_poll_safewake_init(&psw);