block: Align max_hw_sectors to logical blocksize (817046ec) · Commits · 戴 / test

Block device drivers do not have to call blk_queue_max_hw_sectors() to set a limit on request size if the default limit BLK_SAFE_MAX_SECTORS is acceptable. However, this limit (255 sectors) may not be aligned to the device logical block size which cannot be used as is for a request maximum size. This is the case for the null_blk device driver. Modify blk_queue_max_hw_sectors() to make sure that the request size limits specified by the max_hw_sectors and max_sectors queue limits are always aligned to the device logical block size. Additionally, to avoid introducing a dependence on the execution order of this function with blk_queue_logical_block_size(), also modify blk_queue_logical_block_size() to perform the same alignment when the logical block size is set after max_hw_sectors. Signed-off-by:

Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by:

Christoph Hellwig <hch@lst.de> Reviewed-by:

Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/blk-settings.c

+18 −5

Original line number	Diff line number	Diff line
		@@ -157,10 +157,16 @@ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto
		__func__, max_hw_sectors);
		}

		max_hw_sectors = round_down(max_hw_sectors,
		limits->logical_block_size >> SECTOR_SHIFT);
		limits->max_hw_sectors = max_hw_sectors;

		max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
		max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS);
		max_sectors = round_down(max_sectors,
		limits->logical_block_size >> SECTOR_SHIFT);
		limits->max_sectors = max_sectors;

		q->backing_dev_info->io_pages = max_sectors >> (PAGE_SHIFT - 9);
		}
		EXPORT_SYMBOL(blk_queue_max_hw_sectors);
		@@ -321,13 +327,20 @@ EXPORT_SYMBOL(blk_queue_max_segment_size);
		**/
		void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
		{
		q->limits.logical_block_size = size;
		struct queue_limits *limits = &q->limits;

		if (q->limits.physical_block_size < size)
		q->limits.physical_block_size = size;
		limits->logical_block_size = size;

		if (q->limits.io_min < q->limits.physical_block_size)
		q->limits.io_min = q->limits.physical_block_size;
		if (limits->physical_block_size < size)
		limits->physical_block_size = size;

		if (limits->io_min < limits->physical_block_size)
		limits->io_min = limits->physical_block_size;

		limits->max_hw_sectors =
		round_down(limits->max_hw_sectors, size >> SECTOR_SHIFT);
		limits->max_sectors =
		round_down(limits->max_sectors, size >> SECTOR_SHIFT);
		}
		EXPORT_SYMBOL(blk_queue_logical_block_size);

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