Commit 262a3dd0 authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
Browse files

null_blk: single kmap per bio segment 



Rather than kmap the the request bio segment for each sector, do
the mapping just once.

Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Tested-by: default avatarHans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 84592838

drivers/block/null_blk/main.c

+14 −18
Original line number Diff line number Diff line
@@ -1129,8 +1129,8 @@ static int null_make_cache_space(struct nullb *nullb, unsigned long n) 
	return 0;

}



static blk_status_t copy_to_nullb(struct nullb *nullb, struct page *source,

	unsigned int off, sector_t sector, size_t n, bool is_fua)

static blk_status_t copy_to_nullb(struct nullb *nullb, void *source,

				  sector_t sector, size_t n, bool is_fua)

{

	size_t temp, count = 0;

	unsigned int offset;
@@ -1148,7 +1148,7 @@ static blk_status_t copy_to_nullb(struct nullb *nullb, struct page *source, 
		if (!t_page)

			return BLK_STS_NOSPC;



		memcpy_page(t_page->page, offset, source, off + count, temp);

		memcpy_to_page(t_page->page, offset, source + count, temp);



		__set_bit(sector & SECTOR_MASK, t_page->bitmap);
@@ -1161,8 +1161,8 @@ static blk_status_t copy_to_nullb(struct nullb *nullb, struct page *source, 
	return BLK_STS_OK;

}



static void copy_from_nullb(struct nullb *nullb, struct page *dest,

	unsigned int off, sector_t sector, size_t n)

static void copy_from_nullb(struct nullb *nullb, void *dest, sector_t sector,

			    size_t n)

{

	size_t temp, count = 0;

	unsigned int offset;
@@ -1176,22 +1176,16 @@ static void copy_from_nullb(struct nullb *nullb, struct page *dest, 
			!null_cache_active(nullb));



		if (t_page)

			memcpy_page(dest, off + count, t_page->page, offset,

			memcpy_from_page(dest + count, t_page->page, offset,

					 temp);

		else

			memzero_page(dest, off + count, temp);

			memset(dest + count, 0, temp);



		count += temp;

		sector += temp >> SECTOR_SHIFT;

	}

}



static void nullb_fill_pattern(struct nullb *nullb, struct page *page,

			       unsigned int len, unsigned int off)

{

	memset_page(page, off, 0xff, len);

}



blk_status_t null_handle_discard(struct nullb_device *dev,

				 sector_t sector, sector_t nr_sectors)

{
@@ -1240,27 +1234,29 @@ static blk_status_t null_transfer(struct nullb *nullb, struct page *page, 
	struct nullb_device *dev = nullb->dev;

	blk_status_t err = BLK_STS_OK;

	unsigned int valid_len = len;

	void *p;



	p = kmap_local_page(page) + off;

	if (!is_write) {

		if (dev->zoned)

			valid_len = null_zone_valid_read_len(nullb,

				sector, len);



		if (valid_len) {

			copy_from_nullb(nullb, page, off, sector,

					valid_len);

			copy_from_nullb(nullb, p, sector, valid_len);

			off += valid_len;

			len -= valid_len;

		}



		if (len)

			nullb_fill_pattern(nullb, page, len, off);

			memset(p + valid_len, 0xff, len);

		flush_dcache_page(page);

	} else {

		flush_dcache_page(page);

		err = copy_to_nullb(nullb, page, off, sector, len, is_fua);

		err = copy_to_nullb(nullb, p, sector, len, is_fua);

	}



	kunmap_local(p);

	return err;

}