From a6f0788ec2881ac14e97ff7fa6a78a807f87b5ba Mon Sep 17 00:00:00 2001 From: Chaitanya Kulkarni Date: Wed, 30 Nov 2016 12:28:59 -0800 Subject: block: add support for REQ_OP_WRITE_ZEROES This adds a new block layer operation to zero out a range of LBAs. This allows to implement zeroing for devices that don't use either discard with a predictable zero pattern or WRITE SAME of zeroes. The prominent example of that is NVMe with the Write Zeroes command, but in the future, this should also help with improving the way zeroing discards work. For this operation, suitable entry is exported in sysfs which indicate the number of maximum bytes allowed in one write zeroes operation by the device. Signed-off-by: Chaitanya Kulkarni Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-settings.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'block/blk-settings.c') diff --git a/block/blk-settings.c b/block/blk-settings.c index c7ccabc0ec3e..8a2bc124a684 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -96,6 +96,7 @@ void blk_set_default_limits(struct queue_limits *lim) lim->max_dev_sectors = 0; lim->chunk_sectors = 0; lim->max_write_same_sectors = 0; + lim->max_write_zeroes_sectors = 0; lim->max_discard_sectors = 0; lim->max_hw_discard_sectors = 0; lim->discard_granularity = 0; @@ -132,6 +133,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_sectors = UINT_MAX; lim->max_dev_sectors = UINT_MAX; lim->max_write_same_sectors = UINT_MAX; + lim->max_write_zeroes_sectors = UINT_MAX; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -299,6 +301,19 @@ void blk_queue_max_write_same_sectors(struct request_queue *q, } EXPORT_SYMBOL(blk_queue_max_write_same_sectors); +/** + * blk_queue_max_write_zeroes_sectors - set max sectors for a single + * write zeroes + * @q: the request queue for the device + * @max_write_zeroes_sectors: maximum number of sectors to write per command + **/ +void blk_queue_max_write_zeroes_sectors(struct request_queue *q, + unsigned int max_write_zeroes_sectors) +{ + q->limits.max_write_zeroes_sectors = max_write_zeroes_sectors; +} +EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors); + /** * blk_queue_max_segments - set max hw segments for a request for this queue * @q: the request queue for the device @@ -527,6 +542,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors); t->max_write_same_sectors = min(t->max_write_same_sectors, b->max_write_same_sectors); + t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, + b->max_write_zeroes_sectors); t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, -- cgit v1.2.3