Commit e355b253 authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Andrew Morton
Browse files

zram: factor out different page types read 

Similarly to write, split the page read code into ZRAM_HUGE read,
ZRAM_SAME read and compressed page read to simplify the code.

Link: https://lkml.kernel.org/r/20241218063513.297475-6-senozhatsky@chromium.org


Signed-off-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ef932cd2

drivers/block/zram/zram_drv.c

+52 −33
Original line number Diff line number Diff line
@@ -1531,54 +1531,73 @@ static void zram_free_page(struct zram *zram, size_t index) 
	zram_set_obj_size(zram, index, 0);

}



/*

 * Reads (decompresses if needed) a page from zspool (zsmalloc).

 * Corresponding ZRAM slot should be locked.

 */

static int zram_read_from_zspool(struct zram *zram, struct page *page,

static int read_same_filled_page(struct zram *zram, struct page *page,

				 u32 index)

{

	struct zcomp_strm *zstrm;

	unsigned long handle;

	unsigned int size;

	void *src, *dst;

	u32 prio;

	int ret;



	handle = zram_get_handle(zram, index);

	if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) {

	void *mem;



	mem = kmap_local_page(page);

		zram_fill_page(mem, PAGE_SIZE, handle);

	zram_fill_page(mem, PAGE_SIZE, zram_get_handle(zram, index));

	kunmap_local(mem);

	return 0;

}



	size = zram_get_obj_size(zram, index);



	if (size != PAGE_SIZE) {

		prio = zram_get_priority(zram, index);

		zstrm = zcomp_stream_get(zram->comps[prio]);

	}

static int read_incompressible_page(struct zram *zram, struct page *page,

				    u32 index)

{

	unsigned long handle;

	void *src, *dst;



	handle = zram_get_handle(zram, index);

	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);

	if (size == PAGE_SIZE) {

	dst = kmap_local_page(page);

	copy_page(dst, src);

	kunmap_local(dst);

		ret = 0;

	} else {

	zs_unmap_object(zram->mem_pool, handle);



	return 0;

}



static int read_compressed_page(struct zram *zram, struct page *page, u32 index)

{

	struct zcomp_strm *zstrm;

	unsigned long handle;

	unsigned int size;

	void *src, *dst;

	int ret, prio;



	handle = zram_get_handle(zram, index);

	size = zram_get_obj_size(zram, index);

	prio = zram_get_priority(zram, index);



	zstrm = zcomp_stream_get(zram->comps[prio]);

	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);

	dst = kmap_local_page(page);

		ret = zcomp_decompress(zram->comps[prio], zstrm,

				       src, size, dst);

	ret = zcomp_decompress(zram->comps[prio], zstrm, src, size, dst);

	kunmap_local(dst);

		zcomp_stream_put(zram->comps[prio]);

	}

	zs_unmap_object(zram->mem_pool, handle);

	zcomp_stream_put(zram->comps[prio]);



	return ret;

}



/*

 * Reads (decompresses if needed) a page from zspool (zsmalloc).

 * Corresponding ZRAM slot should be locked.

 */

static int zram_read_from_zspool(struct zram *zram, struct page *page,

				 u32 index)

{

	if (zram_test_flag(zram, index, ZRAM_SAME) ||

	    !zram_get_handle(zram, index))

		return read_same_filled_page(zram, page, index);



	if (!zram_test_flag(zram, index, ZRAM_HUGE))

		return read_compressed_page(zram, page, index);

	else

		return read_incompressible_page(zram, page, index);

}



static int zram_read_page(struct zram *zram, struct page *page, u32 index,

			  struct bio *parent)

{