From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id A38756B0270 for ; Thu, 26 Jan 2017 06:58:42 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id 75so308735761pgf.3 for ; Thu, 26 Jan 2017 03:58:42 -0800 (PST) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTPS id u5si26287445pgi.223.2017.01.26.03.58.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 26 Jan 2017 03:58:41 -0800 (PST) From: "Kirill A. Shutemov" Subject: [PATCHv6 12/37] brd: make it handle huge pages Date: Thu, 26 Jan 2017 14:57:54 +0300 Message-Id: <20170126115819.58875-13-kirill.shutemov@linux.intel.com> In-Reply-To: <20170126115819.58875-1-kirill.shutemov@linux.intel.com> References: <20170126115819.58875-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Theodore Ts'o , Andreas Dilger , Jan Kara , Andrew Morton Cc: Alexander Viro , Hugh Dickins , Andrea Arcangeli , Dave Hansen , Vlastimil Babka , Matthew Wilcox , Ross Zwisler , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, "Kirill A. Shutemov" Do not assume length of bio segment is never larger than PAGE_SIZE. With huge pages it's HPAGE_PMD_SIZE (2M on x86-64). Signed-off-by: Kirill A. Shutemov --- drivers/block/brd.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 3adc32a3153b..d2f7dc87b545 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -202,12 +202,15 @@ static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n) size_t copy; copy = min_t(size_t, n, PAGE_SIZE - offset); + n -= copy; if (!brd_insert_page(brd, sector)) return -ENOSPC; - if (copy < n) { + while (n) { sector += copy >> SECTOR_SHIFT; if (!brd_insert_page(brd, sector)) return -ENOSPC; + copy = min_t(size_t, n, PAGE_SIZE); + n -= copy; } return 0; } @@ -242,6 +245,7 @@ static void copy_to_brd(struct brd_device *brd, const void *src, size_t copy; copy = min_t(size_t, n, PAGE_SIZE - offset); + n -= copy; page = brd_lookup_page(brd, sector); BUG_ON(!page); @@ -249,10 +253,11 @@ static void copy_to_brd(struct brd_device *brd, const void *src, memcpy(dst + offset, src, copy); kunmap_atomic(dst); - if (copy < n) { + while (n) { src += copy; sector += copy >> SECTOR_SHIFT; - copy = n - copy; + copy = min_t(size_t, n, PAGE_SIZE); + n -= copy; page = brd_lookup_page(brd, sector); BUG_ON(!page); @@ -274,6 +279,7 @@ static void copy_from_brd(void *dst, struct brd_device *brd, size_t copy; copy = min_t(size_t, n, PAGE_SIZE - offset); + n -= copy; page = brd_lookup_page(brd, sector); if (page) { src = kmap_atomic(page); @@ -282,10 +288,11 @@ static void copy_from_brd(void *dst, struct brd_device *brd, } else memset(dst, 0, copy); - if (copy < n) { + while (n) { dst += copy; sector += copy >> SECTOR_SHIFT; - copy = n - copy; + copy = min_t(size_t, n, PAGE_SIZE); + n -= copy; page = brd_lookup_page(brd, sector); if (page) { src = kmap_atomic(page); -- 2.11.0 -- 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