[PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications

[linux-2.6-omap-h63xx.git] / fs / eventpoll.c

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4284cd31eba6dcb6f125f1fd574aa2213439b45f..a0f682cdd03e06e8802efdf320c6da9d436d31ad 100644 (file)
--- a/fs/eventpoll.c
+++ b/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;
@@ -451,15 +452,6 @@ static void ep_poll_safewake(struct poll_safewake *psw, wait_queue_head_t *wq)
 }
 
 
-/* Used to initialize the epoll bits inside the "struct file" */
-void eventpoll_init_file(struct file *file)
-{
-
-       INIT_LIST_HEAD(&file->f_ep_links);
-       spin_lock_init(&file->f_ep_lock);
-}
-
-
 /*
  * This is called from eventpoll_release() to unlink files from the eventpoll
  * interface. We need to have this facility to cleanup correctly files that are
@@ -477,10 +469,10 @@ 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 +484,7 @@ void eventpoll_release_file(struct file *file)
                up_write(&ep->sem);
        }
 
-       up(&epsem);
+       mutex_unlock(&epmutex);
 }
 
 
@@ -607,7 +599,7 @@ sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event)
        switch (op) {
        case EPOLL_CTL_ADD:
                if (!epi) {
-                       epds.events |= POLLERR | POLLHUP;
+                       epds.events |= POLLERR | POLLHUP | POLLRDHUP;
 
                        error = ep_insert(ep, &epds, tfile, fd);
                } else
@@ -621,7 +613,7 @@ sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event)
                break;
        case EPOLL_CTL_MOD:
                if (epi) {
-                       epds.events |= POLLERR | POLLHUP;
+                       epds.events |= POLLERR | POLLHUP | POLLRDHUP;
                        error = ep_modify(ep, epi, &epds);
                } else
                        error = -ENOENT;
@@ -819,9 +811,9 @@ 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 +835,7 @@ static void ep_free(struct eventpoll *ep)
                ep_remove(ep, epi);
        }
 
-       up(&epsem);
+       mutex_unlock(&epmutex);
 }
 
 
@@ -1615,7 +1607,7 @@ 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);