Commit f575a5ad authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Andrew Morton
Browse files

zram: don't use highmem for the bounce buffer in zram_bvec_{read,write} 

There is no point in allocation a highmem page when we instantly need to
copy from it.

Link: https://lkml.kernel.org/r/20230411171459.567614-9-hch@lst.de


Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 82ca875d

drivers/block/zram/zram_drv.c

+5 −12
Original line number Diff line number Diff line
@@ -1431,7 +1431,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, 
	page = bvec->bv_page;

	if (is_partial_io(bvec)) {

		/* Use a temporary buffer to decompress the page */

		page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);

		page = alloc_page(GFP_NOIO);

		if (!page)

			return -ENOMEM;

	}
@@ -1440,12 +1440,8 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, 
	if (unlikely(ret))

		goto out;



	if (is_partial_io(bvec)) {

		void *src = kmap_atomic(page);



		memcpy_to_bvec(bvec, src + offset);

		kunmap_atomic(src);

	}

	if (is_partial_io(bvec))

		memcpy_to_bvec(bvec, page_address(page) + offset);

out:

	if (is_partial_io(bvec))

		__free_page(page);
@@ -1589,12 +1585,11 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, 


	vec = *bvec;

	if (is_partial_io(bvec)) {

		void *dst;

		/*

		 * This is a partial IO. We need to read the full page

		 * before to write the changes.

		 */

		page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);

		page = alloc_page(GFP_NOIO);

		if (!page)

			return -ENOMEM;
@@ -1602,9 +1597,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, 
		if (ret)

			goto out;



		dst = kmap_atomic(page);

		memcpy_from_bvec(dst + offset, bvec);

		kunmap_atomic(dst);

		memcpy_from_bvec(page_address(page) + offset, bvec);



		bvec_set_page(&vec, page, PAGE_SIZE, 0);

	}