From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 95AA56B037C for ; Tue, 8 Aug 2017 04:47:47 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id v49so12694072qtc.2 for ; Tue, 08 Aug 2017 01:47:47 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id q45si757625qta.414.2017.08.08.01.47.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Aug 2017 01:47:46 -0700 (PDT) From: Ming Lei Subject: [PATCH v3 09/49] block: comment on bio_iov_iter_get_pages() Date: Tue, 8 Aug 2017 16:45:08 +0800 Message-Id: <20170808084548.18963-10-ming.lei@redhat.com> In-Reply-To: <20170808084548.18963-1-ming.lei@redhat.com> References: <20170808084548.18963-1-ming.lei@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jens Axboe , Christoph Hellwig , Huang Ying , Andrew Morton , Alexander Viro Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Ming Lei bio_iov_iter_get_pages() used unused bvec spaces for storing page pointer array temporarily, and this patch comments on this usage wrt. multipage bvec support. Signed-off-by: Ming Lei --- block/bio.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/bio.c b/block/bio.c index 826b5d173416..28697e3c8ce3 100644 --- a/block/bio.c +++ b/block/bio.c @@ -875,6 +875,10 @@ EXPORT_SYMBOL(bio_add_page); * * Pins as many pages from *iter and appends them to @bio's bvec array. The * pages will have to be released using put_page() when done. + * + * The hacking way of using bvec table as page pointer array is safe + * even after multipage bvec is introduced because that space can be + * thought as unused by bio_add_page(). */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { -- 2.9.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org