Merge branch 'master' of /usr/src/ntfs-2.6/

[pandora-kernel.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index 20bb919..aec2b19 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -29,7 +29,6 @@
 #include <linux/highmem.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>
-#include <linux/rcuref.h>
 
 #include <asm/kmap_types.h>
 #include <asm/uaccess.h>
@@ -457,6 +456,8 @@ static inline struct kiocb *aio_get_req(struct kioctx *ctx)
 
 static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
 {
+       assert_spin_locked(&ctx->ctx_lock);
+
        if (req->ki_dtor)
                req->ki_dtor(req);
        kmem_cache_free(kiocb_cachep, req);
@@ -498,6 +499,8 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
        dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n",
                req, atomic_read(&req->ki_filp->f_count));
 
+       assert_spin_locked(&ctx->ctx_lock);
+
        req->ki_users --;
        if (unlikely(req->ki_users < 0))
                BUG();
@@ -510,7 +513,7 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
        /* Must be done under the lock to serialise against cancellation.
         * Call this aio_fput as it duplicates fput via the fput_work.
         */
-       if (unlikely(rcuref_dec_and_test(&req->ki_filp->f_count))) {
+       if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
                get_ioctx(ctx);
                spin_lock(&fput_lock);
                list_add(&req->ki_list, &fput_head);
@@ -619,14 +622,13 @@ static void unuse_mm(struct mm_struct *mm)
  * the kiocb (to tell the caller to activate the work
  * queue to process it), or 0, if it found that it was
  * already queued.
- *
- * Should be called with the spin lock iocb->ki_ctx->ctx_lock
- * held
  */
 static inline int __queue_kicked_iocb(struct kiocb *iocb)
 {
        struct kioctx *ctx = iocb->ki_ctx;
 
+       assert_spin_locked(&ctx->ctx_lock);
+
        if (list_empty(&iocb->ki_run_list)) {
                list_add_tail(&iocb->ki_run_list,
                        &ctx->run_list);
@@ -771,13 +773,15 @@ out:
  *     Process all pending retries queued on the ioctx
  *     run list.
  * Assumes it is operating within the aio issuer's mm
- * context. Expects to be called with ctx->ctx_lock held
+ * context.
  */
 static int __aio_run_iocbs(struct kioctx *ctx)
 {
        struct kiocb *iocb;
        LIST_HEAD(run_list);
 
+       assert_spin_locked(&ctx->ctx_lock);
+
        list_splice_init(&ctx->run_list, &run_list);
        while (!list_empty(&run_list)) {
                iocb = list_entry(run_list.next, struct kiocb,
@@ -937,28 +941,19 @@ int fastcall aio_complete(struct kiocb *iocb, long res, long res2)
        unsigned long   tail;
        int             ret;
 
-       /* Special case handling for sync iocbs: events go directly
-        * into the iocb for fast handling.  Note that this will not 
-        * work if we allow sync kiocbs to be cancelled. in which
-        * case the usage count checks will have to move under ctx_lock
-        * for all cases.
+       /*
+        * Special case handling for sync iocbs:
+        *  - events go directly into the iocb for fast handling
+        *  - the sync task with the iocb in its stack holds the single iocb
+        *    ref, no other paths have a way to get another ref
+        *  - the sync task helpfully left a reference to itself in the iocb
         */
        if (is_sync_kiocb(iocb)) {
-               int ret;
-
+               BUG_ON(iocb->ki_users != 1);
                iocb->ki_user_data = res;
-               if (iocb->ki_users == 1) {
-                       iocb->ki_users = 0;
-                       ret = 1;
-               } else {
-                       spin_lock_irq(&ctx->ctx_lock);
-                       iocb->ki_users--;
-                       ret = (0 == iocb->ki_users);
-                       spin_unlock_irq(&ctx->ctx_lock);
-               }
-               /* sync iocbs put the task here for us */
+               iocb->ki_users = 0;
                wake_up_process(iocb->ki_obj.tsk);
-               return ret;
+               return 1;
        }
 
        info = &ctx->ring_info;
@@ -1613,12 +1608,14 @@ asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
 
 /* lookup_kiocb
  *     Finds a given iocb for cancellation.
- *     MUST be called with ctx->ctx_lock held.
  */
 static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
                                  u32 key)
 {
        struct list_head *pos;
+
+       assert_spin_locked(&ctx->ctx_lock);
+
        /* TODO: use a hash or array, this sucks. */
        list_for_each(pos, &ctx->active_reqs) {
                struct kiocb *kiocb = list_kiocb(pos);