From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: [PATCH v2] block: do not artificially constrain max_sectors for stacking drivers Date: Mon, 9 Jul 2012 10:57:12 -0400 Message-ID: <20120709145711.GB30886@redhat.com> References: <20120709130052.GC30048@redhat.com> <20120709131611.GD30048@redhat.com> <20120709134041.GA30633@redhat.com> <20120709141416.GB30633@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120709141416.GB30633@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: "Chauhan, Vijay" Cc: "dm-devel@redhat.com" , "Moger, Babu" , "Martin K. Petersen" , "Stankey, Robert" , axboe@kernel.dk, linux-kernel@vger.kernel.org List-Id: dm-devel.ids blk_set_stacking_limits() is intended to allow stacking drivers to build up the limits of the stacked device based on the underlying devices' limits. But in the case of 'max_sectors' the default of BLK_DEF_MAX_SECTORS (1024) doesn't allow the stacking driver to inherit a max_sectors larger than 1024. It is now clear that this artificial limit is getting in the way so change blk_set_stacking_limits's max_sectors to UINT_MAX (which allows stacking drivers like dm-multipath to inherit 'max_sectors' from the underlying paths). blk_limits_max_hw_sectors() must allow stacking drivers to not have max_sectors set to BLK_DEF_MAX_SECTORS as a side-effect. Move that historic constraint to blk_queue_max_hw_sectors(). Reported-by: Vijay Chauhan Signed-off-by: Mike Snitzer Cc: Martin K. Petersen --- block/blk-settings.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) v2: tweak blk_limits_max_hw_sectors and blk_queue_max_hw_sectors diff --git a/block/blk-settings.c b/block/blk-settings.c index d3234fc..b808dfd 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -143,8 +143,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->discard_zeroes_data = 1; lim->max_segments = USHRT_MAX; lim->max_hw_sectors = UINT_MAX; - - lim->max_sectors = BLK_DEF_MAX_SECTORS; + lim->max_sectors = UINT_MAX; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -255,8 +254,7 @@ void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_ } limits->max_hw_sectors = max_hw_sectors; - limits->max_sectors = min_t(unsigned int, max_hw_sectors, - BLK_DEF_MAX_SECTORS); + limits->max_sectors = min_not_zero(limits->max_sectors, max_hw_sectors); } EXPORT_SYMBOL(blk_limits_max_hw_sectors); @@ -271,6 +269,8 @@ EXPORT_SYMBOL(blk_limits_max_hw_sectors); void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) { blk_limits_max_hw_sectors(&q->limits, max_hw_sectors); + q->limits.max_sectors = min_t(unsigned int, max_hw_sectors, + BLK_DEF_MAX_SECTORS); } EXPORT_SYMBOL(blk_queue_max_hw_sectors);