Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754744AbaJCSGj (ORCPT ); Fri, 3 Oct 2014 14:06:39 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:51579 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754189AbaJCSGg (ORCPT ); Fri, 3 Oct 2014 14:06:36 -0400 From: Kent Overstreet To: linux-kernel@vger.kernel.org Cc: Kent Overstreet , Benjamin LaHaise , Zach Brown , Jeff Moyer , Jens Axboe , Slava Pestov Subject: [PATCH] aio: Fix return code of io_submit() (RFC) Date: Fri, 3 Oct 2014 11:08:13 -0700 Message-Id: <1412359693-2535-1-git-send-email-kmo@daterainc.com> X-Mailer: git-send-email 2.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org io_submit() could return -EAGAIN on memory allocation failure when it should really have been returning -ENOMEM. This could confuse applications (i.e. fio) since -EAGAIN means "too many requests outstanding, wait until completions have been reaped" and if the application actually was tracking outstanding completions this wouldn't make a lot of sense. NOTE: the man page seems to imply that the current behaviour (-EAGAIN on allocation failure) has always been the case. I don't think it makes a lot of sense, but this should probably be discussed more widely in case applications have somehow come to rely on the current behaviour... Signed-off-by: Kent Overstreet Cc: Benjamin LaHaise Cc: Zach Brown Cc: Jeff Moyer Cc: Jens Axboe Cc: Slava Pestov --- fs/aio.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 733750096b..556547044b 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -933,23 +933,14 @@ static inline struct kiocb *aio_get_req(struct kioctx *ctx) { struct kiocb *req; - if (!get_reqs_available(ctx)) { - user_refill_reqs_available(ctx); - if (!get_reqs_available(ctx)) - return NULL; - } - req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); if (unlikely(!req)) - goto out_put; + return NULL; percpu_ref_get(&ctx->reqs); req->ki_ctx = ctx; return req; -out_put: - put_reqs_available(ctx, 1); - return NULL; } static void kiocb_free(struct kiocb *req) @@ -1489,9 +1480,17 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, return -EINVAL; } + if (!get_reqs_available(ctx)) { + user_refill_reqs_available(ctx); + if (!get_reqs_available(ctx)) + return -EAGAIN; + } + req = aio_get_req(ctx); - if (unlikely(!req)) - return -EAGAIN; + if (unlikely(!req)) { + ret = -ENOMEM; + goto out_put; + } req->ki_filp = fget(iocb->aio_fildes); if (unlikely(!req->ki_filp)) { @@ -1533,9 +1532,10 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, return 0; out_put_req: - put_reqs_available(ctx, 1); percpu_ref_put(&ctx->reqs); kiocb_free(req); +out_put: + put_reqs_available(ctx, 1); return ret; } -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/