Allow block drivers to configure the following if CONFIG_BLK_SUB_PAGE_SEGMENTS=y: * Maximum number of hardware sectors values smaller than PAGE_SIZE >> SECTOR_SHIFT. With PAGE_SIZE = 4096 this means that values below 8 are supported. * A maximum segment size smaller than the page size. This is most useful for page sizes above 4096 bytes. The behavior of the block layer is not modified if CONFIG_BLK_SUB_PAGE_SEGMENTS=n. Cc: Christoph Hellwig <hch@xxxxxx> Cc: Ming Lei <ming.lei@xxxxxxxxxx> Cc: Keith Busch <kbusch@xxxxxxxxxx> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> --- block/blk-settings.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/block/blk-settings.c b/block/blk-settings.c index 9c9713c9269c..9820ceb18c46 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -122,12 +122,14 @@ EXPORT_SYMBOL(blk_queue_bounce_limit); void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) { struct queue_limits *limits = &q->limits; + unsigned int min_max_hw_sectors = blk_queue_sub_page_segments(q) ? 1 : + PAGE_SIZE >> SECTOR_SHIFT; unsigned int max_sectors; - if ((max_hw_sectors << 9) < PAGE_SIZE) { - max_hw_sectors = 1 << (PAGE_SHIFT - 9); - printk(KERN_INFO "%s: set to minimum %d\n", - __func__, max_hw_sectors); + if (max_hw_sectors < min_max_hw_sectors) { + max_hw_sectors = min_max_hw_sectors; + printk(KERN_INFO "%s: set to minimum %u\n", __func__, + max_hw_sectors); } max_hw_sectors = round_down(max_hw_sectors, @@ -282,10 +284,12 @@ EXPORT_SYMBOL_GPL(blk_queue_max_discard_segments); **/ void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) { - if (max_size < PAGE_SIZE) { - max_size = PAGE_SIZE; - printk(KERN_INFO "%s: set to minimum %d\n", - __func__, max_size); + unsigned int min_max_segment_size = blk_queue_sub_page_segments(q) ? + SECTOR_SIZE : PAGE_SIZE; + + if (max_size < min_max_segment_size) { + max_size = min_max_segment_size; + printk(KERN_INFO "%s: set to minimum %u\n", __func__, max_size); } /* see blk_queue_virt_boundary() for the explanation */