epoll cleanups: epoll remove static pre-declarations and akpm-ize the code

Re-arrange epoll code to avoid static functions pre-declarations, and apply
akpm-filter on it.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 486 insertions, 548 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index e224abfd9197..1aad34ea61a4 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -41,7 +41,6 @@
 #include <asm/atomic.h>
 #include <asm/semaphore.h>
 
-
 /*
  * LOCKING:
  * There are three level of locking required by epoll :
@@ -74,7 +73,6 @@
  * a greater scalability.
  */
 
-
 #define DEBUG_EPOLL 0
 
 #if DEBUG_EPOLL > 0
@@ -104,7 +102,6 @@
 
 #define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))
 
-
 struct epoll_filefd {
         struct file *file;
         int fd;
@@ -222,36 +219,6 @@ struct ep_pqueue {
         struct epitem *epi;
 };
 
-
-
-static void ep_poll_safewake_init(struct poll_safewake *psw);
-static void ep_poll_safewake(struct poll_safewake *psw, wait_queue_head_t *wq);
-static int ep_alloc(struct eventpoll **pep);
-static void ep_free(struct eventpoll *ep);
-static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd);
-static void ep_use_epitem(struct epitem *epi);
-static void ep_release_epitem(struct epitem *epi);
-static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
-                                 poll_table *pt);
-static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi);
-static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
-                     struct file *tfile, int fd);
-static int ep_modify(struct eventpoll *ep, struct epitem *epi,
-                     struct epoll_event *event);
-static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi);
-static int ep_unlink(struct eventpoll *ep, struct epitem *epi);
-static int ep_remove(struct eventpoll *ep, struct epitem *epi);
-static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *key);
-static int ep_eventpoll_close(struct inode *inode, struct file *file);
-static unsigned int ep_eventpoll_poll(struct file *file, poll_table *wait);
-static int ep_send_events(struct eventpoll *ep, struct list_head *txlist,
-                          struct epoll_event __user *events, int maxevents);
-static int ep_events_transfer(struct eventpoll *ep,
-                              struct epoll_event __user *events,
-                              int maxevents);
-static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
-                   int maxevents, long timeout);
-
 /*
  * This semaphore is used to serialize ep_free() and eventpoll_release_file().
  */
@@ -266,19 +233,6 @@ static struct kmem_cache *epi_cache __read_mostly;
 /* Slab cache used to allocate "struct eppoll_entry" */
 static struct kmem_cache *pwq_cache __read_mostly;
 
-/* File callbacks that implement the eventpoll file behaviour */
-static const struct file_operations eventpoll_fops = {
-        .release        = ep_eventpoll_close,
-        .poll           = ep_eventpoll_poll
-};
-
-
-
-/* Fast test to see if the file is an evenpoll file */
-static inline int is_file_epoll(struct file *f)
-{
-        return f->f_op == &eventpoll_fops;
-}
 
 /* Setup the structure that is used as key for the rb-tree */
 static inline void ep_set_ffd(struct epoll_filefd *ffd,
@@ -347,7 +301,6 @@ static void ep_poll_safewake_init(struct poll_safewake *psw)
         spin_lock_init(&psw->lock);
 }
 
-
 /*
  * Perform a safe wake up of the poll wait list. The problem is that
  * with the new callback'd wake up system, it is possible that the
@@ -402,325 +355,145 @@ static void ep_poll_safewake(struct poll_safewake *psw, wait_queue_head_t *wq)
         spin_unlock_irqrestore(&psw->lock, flags);
 }
 
-
 /*
- * 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
- * closed without being removed from the eventpoll interface.
+ * This function unregister poll callbacks from the associated file descriptor.
+ * Since this must be called without holding "ep->lock" the atomic exchange trick
+ * will protect us from multiple unregister.
  */
-void eventpoll_release_file(struct file *file)
+static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi)
 {
-        struct list_head *lsthead = &file->f_ep_links;
-        struct eventpoll *ep;
-        struct epitem *epi;
+        int nwait;
+        struct list_head *lsthead = &epi->pwqlist;
+        struct eppoll_entry *pwq;
 
-        /*
-         * We don't want to get "file->f_ep_lock" because it is not
-         * necessary. It is not necessary because we're in the "struct 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 "epmutex" because ep_remove() requires it when called
-         * from anywhere but ep_free().
-         */
-        mutex_lock(&epmutex);
+        /* This is called without locks, so we need the atomic exchange */
+        nwait = xchg(&epi->nwait, 0);
 
-        while (!list_empty(lsthead)) {
-                epi = list_first_entry(lsthead, struct epitem, fllink);
+        if (nwait) {
+                while (!list_empty(lsthead)) {
+                        pwq = list_first_entry(lsthead, struct eppoll_entry, llink);
 
-                ep = epi->ep;
-                list_del_init(&epi->fllink);
-                down_write(&ep->sem);
-                ep_remove(ep, epi);
-                up_write(&ep->sem);
+                        list_del_init(&pwq->llink);
+                        remove_wait_queue(pwq->whead, &pwq->wait);
+                        kmem_cache_free(pwq_cache, pwq);
+                }
         }
-
-        mutex_unlock(&epmutex);
 }
 
-
 /*
- * It opens an eventpoll file descriptor by suggesting a storage of "size"
- * file descriptors. The size parameter is just an hint about how to size
- * data structures. It won't prevent the user to store more than "size"
- * file descriptors inside the epoll interface. It is the kernel part of
- * the userspace epoll_create(2).
+ * Unlink the "struct epitem" from all places it might have been hooked up.
+ * This function must be called with write IRQ lock on "ep->lock".
  */
-asmlinkage long sys_epoll_create(int size)
+static int ep_unlink(struct eventpoll *ep, struct epitem *epi)
 {
-        int error, fd = -1;
-        struct eventpoll *ep;
-        struct inode *inode;
-        struct file *file;
-
-        DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d)\n",
-                     current, size));
-
-        /*
-         * Sanity check on the size parameter, and create the internal data
-         * structure ( "struct eventpoll" ).
-         */
-        error = -EINVAL;
-        if (size <= 0 || (error = ep_alloc(&ep)) != 0)
-                goto eexit_1;
+        int error;