1 files changed, 65 insertions, 29 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 8ca8df1c3550..958286536a10 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -151,6 +151,38 @@ struct kioctx {
         unsigned                id;
 };
 
+/*
+ * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
+ * cancelled or completed (this makes a certain amount of sense because
+ * successful cancellation - io_cancel() - does deliver the completion to
+ * userspace).
+ *
+ * And since most things don't implement kiocb cancellation and we'd really like
+ * kiocb completion to be lockless when possible, we use ki_cancel to
+ * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
+ * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
+ */
+#define KIOCB_CANCELLED         ((void *) (~0ULL))
+
+struct aio_kiocb {
+        struct kiocb            common;
+
+        struct kioctx           *ki_ctx;
+        kiocb_cancel_fn         *ki_cancel;
+
+        struct iocb __user      *ki_user_iocb;  /* user's aiocb */
+        __u64                   ki_user_data;   /* user's data for completion */
+
+        struct list_head        ki_list;        /* the aio core uses this
+                                                 * for cancellation */
+
+        /*
+         * If the aio_resfd field of the userspace iocb is not zero,
+         * this is the underlying eventfd context to deliver events to.
+         */
+        struct eventfd_ctx      *ki_eventfd;
+};
+
 /*------ sysctl variables----*/
 static DEFINE_SPINLOCK(aio_nr_lock);
 unsigned long aio_nr;           /* current system wide number of aio requests */
@@ -220,7 +252,7 @@ static int __init aio_setup(void)
         if (IS_ERR(aio_mnt))
                 panic("Failed to create aio fs mount.");
 
-        kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
+        kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
         kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
 
         pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page));
@@ -480,8 +512,9 @@ static int aio_setup_ring(struct kioctx *ctx)
 #define AIO_EVENTS_FIRST_PAGE   ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
 #define AIO_EVENTS_OFFSET       (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
 
-void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel)
+void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
 {
+        struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, common);
         struct kioctx *ctx = req->ki_ctx;
         unsigned long flags;
 
@@ -496,7 +529,7 @@ void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel)
 }
 EXPORT_SYMBOL(kiocb_set_cancel_fn);
 
-static int kiocb_cancel(struct kiocb *kiocb)
+static int kiocb_cancel(struct aio_kiocb *kiocb)
 {
         kiocb_cancel_fn *old, *cancel;
 
@@ -514,7 +547,7 @@ static int kiocb_cancel(struct kiocb *kiocb)
                 cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED);
         } while (cancel != old);
 
-        return cancel(kiocb);
+        return cancel(&kiocb->common);
 }
 
 static void free_ioctx(struct work_struct *work)
@@ -550,13 +583,13 @@ static void free_ioctx_reqs(struct percpu_ref *ref)
 static void free_ioctx_users(struct percpu_ref *ref)
 {
         struct kioctx *ctx = container_of(ref, struct kioctx, users);
-        struct kiocb *req;
+        struct aio_kiocb *req;
 
         spin_lock_irq(&ctx->ctx_lock);
 
         while (!list_empty(&ctx->active_reqs)) {
                 req = list_first_entry(&ctx->active_reqs,
-                                       struct kiocb, ki_list);
+                                       struct aio_kiocb, ki_list);
 
                 list_del_init(&req->ki_list);
                 kiocb_cancel(req);
@@ -932,9 +965,9 @@ static void user_refill_reqs_available(struct kioctx *ctx)
  *      Allocate a slot for an aio request.
  * Returns NULL if no requests are free.
  */
-static inline struct kiocb *aio_get_req(struct kioctx *ctx)
+static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
 {
-        struct kiocb *req;
+        struct aio_kiocb *req;
 
         if (!get_reqs_available(ctx)) {
                 user_refill_reqs_available(ctx);
@@ -955,10 +988,10 @@ out_put:
         return NULL;
 }
 
-static void kiocb_free(struct kiocb *req)
+static void kiocb_free(struct aio_kiocb *req)
 {
-        if (req->ki_filp)
-                fput(req->ki_filp);
+        if (req->common.ki_filp)
+                fput(req->common.ki_filp);
         if (req->ki_eventfd != NULL)
                 eventfd_ctx_put(req->ki_eventfd);
         kmem_cache_free(kiocb_cachep, req);
@@ -994,8 +1027,9 @@ out:
 /* aio_complete
  *      Called when the io request on the given iocb is complete.
  */
-void aio_complete(struct kiocb *iocb, long res, long res2)
+static void aio_complete(struct kiocb *kiocb, long res, long res2)
 {
+        struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, common);
         struct kioctx   *ctx = iocb->ki_ctx;
         struct aio_ring *ring;
         struct io_event *ev_page, *event;
@@ -1009,7 +1043,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
          *    ref, no other paths have a way to get another ref
          *  - the sync task helpfully left a reference to itself in the iocb
          */
-        BUG_ON(is_sync_kiocb(iocb));
+        BUG_ON(is_sync_kiocb(kiocb));
 
         if (iocb->ki_list.next) {
                 unsigned long flags;
@@ -1035,7 +1069,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
         ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
         event = ev_page + pos % AIO_EVENTS_PER_PAGE;
 
-        event->obj = (u64)(unsigned long)iocb->ki_obj.user;
+        event->obj = (u64)(unsigned long)iocb->ki_user_iocb;
         event->data = iocb->ki_user_data;
         event->res = res;
         event->res2 = res2;
@@ -1044,7 +1078,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
         flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
 
         pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
-                 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
+                 ctx, tail, iocb, iocb->ki_user_iocb, iocb->ki_user_data,
                  res, res2);
 
         /* after flagging the request as done, we
@@ -1091,7 +1125,6 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
 
         percpu_ref_put(&ctx->reqs);
 }
-EXPORT_SYMBOL(aio_complete);
 
 /* aio_read_events_ring
  *      Pull an event off of the ioctx's event ring.  Returns the number of
@@ -1480,7 +1513,7 @@ rw_common:
 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                          struct iocb *iocb, bool compat)
 {
-        struct kiocb *req;
+        struct aio_kiocb *req;
         ssize_t ret;
 
         /* enforce forwards compatibility on users */
@@ -1503,11 +1536,14 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
         if (unlikely(!req))
                 return -EAGAIN;
 
-        req->ki_filp = fget(iocb->aio_fildes);
-        if (unlikely(!req->ki_filp)) {
+        req->common.ki_filp = fget(iocb->aio_fildes);
+        if (unlikely(!req->common.ki_filp)) {
                 ret = -EBADF;
                 goto out_put_req;
         }
+        req->common.ki_pos = iocb->aio_offset;
+        req->common.ki_complete = aio_complete;
+        req->common.ki_flags = 0;
 
         if (iocb->aio_flags & IOCB_FLAG_RESFD) {
                 /*
@@ -1522,6 +1558,8 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                         req->ki_eventfd = NULL;
                         goto out_put_req;
                 }
+
+                req->common.ki_flags |= IOCB_EVENTFD;
         }
 
         ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
@@ -1530,11 +1568,10 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                 goto out_put_req;
         }
 
-        req->ki_obj.user = user_iocb;
+        req->ki_user_iocb = user_iocb;
         req->ki_user_data = iocb->aio_data;
-        req->ki_pos = iocb->aio_offset;
 
-        ret = aio_run_iocb(req, iocb->aio_lio_opcode,
+        ret = aio_run_iocb(&req->common, iocb->aio_lio_opcode,
                            (char __user *)(unsigned long)iocb->aio_buf,
                            iocb->aio_nbytes,
                            compat);
@@ -1623,10 +1660,10 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
 /* lookup_kiocb
  *      Finds a given iocb for cancellation.
  */
-static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
-                                  u32 key)
+static struct aio_kiocb *
+lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, u32 key)
 {
-        struct list_head *pos;
+        struct aio_kiocb *kiocb;
 
         assert_spin_locked(&ctx->ctx_lock);
 
@@ -1634,9 +1671,8 @@ static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
                 return NULL;
 
         /* TODO: use a hash or array, this sucks. */
-        list_for_each(pos, &ctx->active_reqs) {
-                struct kiocb *kiocb = list_kiocb(pos);
-                if (kiocb->ki_obj.user == iocb)
+        list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
+                if (kiocb->ki_user_iocb == iocb)
                         return kiocb;
         }
         return NULL;
@@ -1656,7 +1692,7 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
                 struct io_event __user *, result)
 {
         struct kioctx *ctx;
-        struct kiocb *kiocb;
+        struct aio_kiocb *kiocb;
         u32 key;
         int ret;