From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: [PATCH 5/5] brd: Request from fdisk 4k alignment Date: Wed, 27 Aug 2014 18:32:32 +0300 Message-ID: <53FDFA10.7040003@plexistor.com> References: <53FDF7AD.5000709@plexistor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Ross Zwisler , linux-kernel , linux-fsdevel To: Jens Axboe , Matthew Wilcox , Dmitry Monakhov Return-path: In-Reply-To: <53FDF7AD.5000709@plexistor.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org From: Boaz Harrosh Because of the direct_access() API which returns a PFN. partitions better start on 4K boundary, else offset ZERO of a partition will not be aligned and blk_direct_access() will fail the call. By setting blk_queue_physical_block_size(PAGE_SIZE) we can communicate this to fdisk and friends. Note that blk_queue_physical_block_size() also trashes io_min, but we can leave this one to be 512. Signed-off-by: Boaz Harrosh --- drivers/block/brd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 83e3d22..6cc3034 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -503,10 +503,17 @@ static struct brd_device *brd_alloc(int i) brd->brd_queue = blk_alloc_queue(GFP_KERNEL); if (!brd->brd_queue) goto out_free_dev; + blk_queue_make_request(brd->brd_queue, brd_make_request); blk_queue_max_hw_sectors(brd->brd_queue, 1024); blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY); + /* This is so fdisk will align partitions on 4k, because of + * direct_access API needing 4k alignment, returning a PFN + */ + blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE); + brd->brd_queue->limits.io_min = 512; /* Don't use the accessor */ + brd->brd_queue->limits.discard_granularity = PAGE_SIZE; brd->brd_queue->limits.max_discard_sectors = UINT_MAX; brd->brd_queue->limits.discard_zeroes_data = 1; -- 1.9.3