linux-kernel - [PATCH 7/8] deal with get_reqs_available() in aio_get

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Date:   Sun, 10 Mar 2019 07:08:21 +0000
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Eric Dumazet <eric.dumazet@...il.com>,
        David Miller <davem@...emloft.net>,
        Jason Baron <jbaron@...mai.com>, kgraul@...ux.ibm.com,
        ktkhai@...tuozzo.com, kyeongdon.kim@....com,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        Netdev <netdev@...r.kernel.org>, pabeni@...hat.com,
        syzkaller-bugs@...glegroups.com, xiyou.wangcong@...il.com,
        Christoph Hellwig <hch@....de>,
        zhengbin <zhengbin13@...wei.com>, bcrl@...ck.org,
        linux-fsdevel@...r.kernel.org, linux-aio@...ck.org,
        houtao1@...wei.com, yi.zhang@...wei.com
Subject: [PATCH 7/8] deal with get_reqs_available() in aio_get_req() itself

From: Al Viro <viro@...iv.linux.org.uk>

simplifies the caller

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/aio.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 595c19965a8b..66ca52c57cca 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1033,6 +1033,11 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
 	if (unlikely(!req))
 		return NULL;
 
+	if (unlikely(!get_reqs_available(ctx))) {
+		kfree(req);
+		return NULL;
+	}
+
 	percpu_ref_get(&ctx->reqs);
 	req->ki_ctx = ctx;
 	INIT_LIST_HEAD(&req->ki_list);
@@ -1796,13 +1801,9 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
 		return -EINVAL;
 	}
 
-	if (!get_reqs_available(ctx))
-		return -EAGAIN;
-
-	ret = -EAGAIN;
 	req = aio_get_req(ctx);
 	if (unlikely(!req))
-		goto out_put_reqs_available;
+		return -EAGAIN;
 
 	req->ki_filp = fget(iocb->aio_fildes);
 	ret = -EBADF;
@@ -1877,7 +1878,6 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
 
 out_put_req:
 	iocb_destroy(req);
-out_put_reqs_available:
 	put_reqs_available(ctx, 1);
 	return ret;
 }
-- 
2.11.0