From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: [PATCH 4/4] brd: Request from fdisk 4k alignment Date: Wed, 06 Aug 2014 14:35:51 +0300 Message-ID: <53E21317.7080403@plexistor.com> References: <53E21125.9080308@plexistor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: linux-fsdevel To: Jens Axboe , Ross Zwisler , Matthew Wilcox , linux-kernel Return-path: Received: from mail-we0-f181.google.com ([74.125.82.181]:50442 "EHLO mail-we0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754750AbaHFLfz (ORCPT ); Wed, 6 Aug 2014 07:35:55 -0400 Received: by mail-we0-f181.google.com with SMTP id k48so2420131wev.26 for ; Wed, 06 Aug 2014 04:35:54 -0700 (PDT) In-Reply-To: <53E21125.9080308@plexistor.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 9673704..514cfe1 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -495,10 +495,17 @@ 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