dm cache: avoid 64 bit division on 32 bit (414dd67d) · Commits · 戴 / test

drivers/md/dm-cache-target.c

+14 −7

Original line number	Diff line number	Diff line
		@@ -158,7 +158,7 @@ struct cache {
		/*
		* origin_blocks entries, discarded if set.
		*/
		sector_t discard_block_size; /* a power of 2 times sectors per block */
		uint32_t discard_block_size; /* a power of 2 times sectors per block */
		dm_dblock_t discard_nr_blocks;
		unsigned long *discard_bitset;

		@@ -412,17 +412,24 @@ static bool block_size_is_power_of_two(struct cache *cache)
		return cache->sectors_per_block_shift >= 0;
		}

		static dm_block_t block_div(dm_block_t b, uint32_t n)
		{
		do_div(b, n);

		return b;
		}

		static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
		{
		sector_t discard_blocks = cache->discard_block_size;
		uint32_t discard_blocks = cache->discard_block_size;
		dm_block_t b = from_oblock(oblock);

		if (!block_size_is_power_of_two(cache))
		(void) sector_div(discard_blocks, cache->sectors_per_block);
		discard_blocks = discard_blocks / cache->sectors_per_block;
		else
		discard_blocks >>= cache->sectors_per_block_shift;

		(void) sector_div(b, discard_blocks);
		b = block_div(b, discard_blocks);

		return to_dblock(b);
		}
		@@ -1002,7 +1009,7 @@ static void process_discard_bio(struct cache cache, struct bio bio)
		dm_block_t end_block = bio->bi_sector + bio_sectors(bio);
		dm_block_t b;

		(void) sector_div(end_block, cache->discard_block_size);
		end_block = block_div(end_block, cache->discard_block_size);

		for (b = start_block; b < end_block; b++)
		set_discard(cache, to_dblock(b));
		@@ -1835,7 +1842,7 @@ static int cache_create(struct cache_args ca, struct cache *result)

		/* FIXME: factor out this whole section */
		origin_blocks = cache->origin_sectors = ca->origin_sectors;
		(void) sector_div(origin_blocks, ca->block_size);
		origin_blocks = block_div(origin_blocks, ca->block_size);
		cache->origin_blocks = to_oblock(origin_blocks);

		cache->sectors_per_block = ca->block_size;
		@@ -1848,7 +1855,7 @@ static int cache_create(struct cache_args ca, struct cache *result)
		dm_block_t cache_size = ca->cache_sectors;

		cache->sectors_per_block_shift = -1;
		(void) sector_div(cache_size, ca->block_size);
		cache_size = block_div(cache_size, ca->block_size);
		cache->cache_size = to_cblock(cache_size);
		} else {
		cache->sectors_per_block_shift = __ffs(ca->block_size);

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