[PATCH 3/8] aio: store event at final iocb_put()

[Al Viro]

From: Al Viro <v...@zeniv.linux.org.uk>

Instead of having aio_complete() set ->ki_res.{res,res2}, do that
explicitly in its callers, drop the reference (as aio_complete()
used to do) and delay the rest until the final iocb_put().

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
---
 fs/aio.c | 45 ++++++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 2249a7a1d6b3..b9c4c1894020 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1077,24 +1077,10 @@ static inline void iocb_destroy(struct aio_kiocb *iocb)
        kmem_cache_free(kiocb_cachep, iocb);
 }
 
-static inline void iocb_put(struct aio_kiocb *iocb)
-{
-       if (refcount_dec_and_test(&iocb->ki_refcnt))
-               iocb_destroy(iocb);
-}
-
-static void aio_fill_event(struct io_event *ev, struct aio_kiocb *iocb,
-                          long res, long res2)
-{
-       iocb->ki_res.res = res;
-       iocb->ki_res.res2 = res2;
-       *ev = iocb->ki_res;
-}
-
 /* aio_complete
  *     Called when the io request on the given iocb is complete.
  */
-static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
+static void aio_complete(struct aio_kiocb *iocb)
 {
        struct kioctx   *ctx = iocb->ki_ctx;
        struct aio_ring *ring;
@@ -1118,14 +1104,14 @@ static void aio_complete(struct aio_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;
 
-       aio_fill_event(event, iocb, res, res2);
+       *event = iocb->ki_res;
 
        kunmap_atomic(ev_page);
        flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
 
-       pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
+       pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n",
                 ctx, tail, iocb, (void __user *)iocb->ki_res.obj, 
iocb->ki_res.data,
-                res, res2);
+                iocb->ki_res.res, iocb->ki_res.res2);
 
        /* after flagging the request as done, we
         * must never even look at it again
@@ -1167,7 +1153,14 @@ static void aio_complete(struct aio_kiocb *iocb, long 
res, long res2)
 
        if (waitqueue_active(&ctx->wait))
                wake_up(&ctx->wait);
-       iocb_put(iocb);
+}
+
+static inline void iocb_put(struct aio_kiocb *iocb)
+{
+       if (refcount_dec_and_test(&iocb->ki_refcnt)) {
+               aio_complete(iocb);
+               iocb_destroy(iocb);
+       }
 }
 
 /* aio_read_events_ring
@@ -1441,7 +1434,9 @@ static void aio_complete_rw(struct kiocb *kiocb, long 
res, long res2)
                file_end_write(kiocb->ki_filp);
        }
 
-       aio_complete(iocb, res, res2);
+       iocb->ki_res.res = res;
+       iocb->ki_res.res2 = res2;
+       iocb_put(iocb);
 }
 
 static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
@@ -1589,11 +1584,10 @@ static ssize_t aio_write(struct kiocb *req, const 
struct iocb *iocb,
 
 static void aio_fsync_work(struct work_struct *work)
 {
-       struct fsync_iocb *req = container_of(work, struct fsync_iocb, work);
-       int ret;
+       struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, 
fsync.work);
 
-       ret = vfs_fsync(req->file, req->datasync);
-       aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
+       iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
+       iocb_put(iocb);
 }
 
 static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
@@ -1614,7 +1608,8 @@ static int aio_fsync(struct fsync_iocb *req, const struct 
iocb *iocb,
 
 static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
 {
-       aio_complete(iocb, mangle_poll(mask), 0);
+       iocb->ki_res.res = mangle_poll(mask);
+       iocb_put(iocb);
 }
 
 static void aio_poll_complete_work(struct work_struct *work)
-- 
2.11.0