[PATCH] update FSF address in COPYING

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

diff --git a/fs/aio.c b/fs/aio.c
index 7afa222..38f6268 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -29,6 +29,7 @@
 #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>
@@ -58,6 +59,7 @@ static DEFINE_SPINLOCK(fput_lock);
 static LIST_HEAD(fput_head);
 
 static void aio_kick_handler(void *);
+static void aio_queue_work(struct kioctx *);
 
 /* aio_setup
  *     Creates the slab caches used by the aio routines, panic on
@@ -498,7 +500,7 @@ 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(atomic_dec_and_test(&req->ki_filp->f_count))) {
+       if (unlikely(rcuref_dec_and_test(&req->ki_filp->f_count))) {
                get_ioctx(ctx);
                spin_lock(&fput_lock);
                list_add(&req->ki_list, &fput_head);
@@ -545,6 +547,24 @@ struct kioctx *lookup_ioctx(unsigned long ctx_id)
        return ioctx;
 }
 
+static int lock_kiocb_action(void *param)
+{
+       schedule();
+       return 0;
+}
+
+static inline void lock_kiocb(struct kiocb *iocb)
+{
+       wait_on_bit_lock(&iocb->ki_flags, KIF_LOCKED, lock_kiocb_action,
+                        TASK_UNINTERRUPTIBLE);
+}
+
+static inline void unlock_kiocb(struct kiocb *iocb)
+{
+       kiocbClearLocked(iocb);
+       wake_up_bit(&iocb->ki_flags, KIF_LOCKED);
+}
+
 /*
  * use_mm
  *     Makes the calling kernel thread take on the specified
@@ -566,6 +586,10 @@ static void use_mm(struct mm_struct *mm)
        atomic_inc(&mm->mm_count);
        tsk->mm = mm;
        tsk->active_mm = mm;
+       /*
+        * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
+        * it won't work. Update it accordingly if you change it here
+        */
        activate_mm(active_mm, mm);
        task_unlock(tsk);
 
@@ -747,6 +771,14 @@ out:
                 * has already been kicked */
                if (kiocbIsKicked(iocb)) {
                        __queue_kicked_iocb(iocb);
+
+                       /*
+                        * __queue_kicked_iocb will always return 1 here, because
+                        * iocb->ki_run_list is empty at this point so it should
+                        * be safe to unconditionally queue the context into the
+                        * work queue.
+                        */
+                       aio_queue_work(ctx);
                }
        }
        return ret;
@@ -773,7 +805,9 @@ static int __aio_run_iocbs(struct kioctx *ctx)
                 * Hold an extra reference while retrying i/o.
                 */
                iocb->ki_users++;       /* grab extra reference */
+               lock_kiocb(iocb);
                aio_run_iocb(iocb);
+               unlock_kiocb(iocb);
                if (__aio_put_req(ctx, iocb))  /* drop extra ref */
                        put_ioctx(ctx);
        }
@@ -1514,10 +1548,9 @@ int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                goto out_put_req;
 
        spin_lock_irq(&ctx->ctx_lock);
-       if (likely(list_empty(&ctx->run_list))) {
-               aio_run_iocb(req);
-       } else {
-               list_add_tail(&req->ki_run_list, &ctx->run_list);
+       aio_run_iocb(req);
+       unlock_kiocb(req);
+       if (!list_empty(&ctx->run_list)) {
                /* drain the run list */
                while (__aio_run_iocbs(ctx))
                        ;
@@ -1648,6 +1681,7 @@ asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
        if (NULL != cancel) {
                struct io_event tmp;
                pr_debug("calling cancel\n");
+               lock_kiocb(kiocb);
                memset(&tmp, 0, sizeof(tmp));
                tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
                tmp.data = kiocb->ki_user_data;
@@ -1659,8 +1693,9 @@ asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
                        if (copy_to_user(result, &tmp, sizeof(tmp)))
                                ret = -EFAULT;
                }
+               unlock_kiocb(kiocb);
        } else
-               printk(KERN_DEBUG "iocb has no cancel operation\n");
+               ret = -EINVAL;
 
        put_ioctx(ctx);