[PATCH 10/27] aio: don't zero entire aio_kiocb aio_get_req()

[Jens Axboe <axboe@xxxxxxxxx>]

It's 192 bytes, fairly substantial. Most items don't need to be cleared,
especially not upfront. Clear the ones we do need to clear, and leave
the other ones for setup when the iocb is prepared and submitted.

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
 fs/aio.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index eaceb40e6cf5..681f2072f81b 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1009,14 +1009,15 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
 {
 	struct aio_kiocb *req;
 
-	req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
-	if (unlikely(!req))
-		return NULL;
+	req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
+	if (req) {
+		percpu_ref_get(&ctx->reqs);
+		req->ki_ctx = ctx;
+		INIT_LIST_HEAD(&req->ki_list);
+		refcount_set(&req->ki_refcnt, 0);
+		req->ki_eventfd = NULL;
+	}
 
-	percpu_ref_get(&ctx->reqs);
-	INIT_LIST_HEAD(&req->ki_list);
-	refcount_set(&req->ki_refcnt, 0);
-	req->ki_ctx = ctx;
 	return req;
 }
 
@@ -1730,6 +1731,10 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
 	if (unlikely(!req->file))
 		return -EBADF;
 
+	req->head = NULL;
+	req->woken = false;
+	req->cancelled = false;
+
 	apt.pt._qproc = aio_poll_queue_proc;
 	apt.pt._key = req->events;
 	apt.iocb = aiocb;
-- 
2.17.1