linux-kernel - [PATCH 4.19 069/100] aio: dont zero entire aio_kiocb aio_get

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Message-Id: <20190430113612.026422243@linuxfoundation.org>
Date:   Tue, 30 Apr 2019 13:38:38 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Jens Axboe <axboe@...nel.dk>,
        Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 4.19 069/100] aio: dont zero entire aio_kiocb aio_get_req()

From: Jens Axboe <axboe@...nel.dk>

commit 2bc4ca9bb600cbe36941da2b2a67189fc4302a04 upstream.

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.

Reviewed-by: Christoph Hellwig <hch@....de>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Cc: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/aio.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1010,14 +1010,15 @@ static inline struct aio_kiocb *aio_get_
 {
 	struct aio_kiocb *req;
 
-	req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
+	req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
 	if (unlikely(!req))
 		return NULL;
 
 	percpu_ref_get(&ctx->reqs);
+	req->ki_ctx = ctx;
 	INIT_LIST_HEAD(&req->ki_list);
 	refcount_set(&req->ki_refcnt, 0);
-	req->ki_ctx = ctx;
+	req->ki_eventfd = NULL;
 	return req;
 }
 
@@ -1738,6 +1739,10 @@ static ssize_t aio_poll(struct aio_kiocb
 	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;