Commit 5561347a authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Andrew Morton
Browse files

zram: factor out WB and non-WB zram read functions 

We will use non-WB variant in ZRAM page recompression path.

Link: https://lkml.kernel.org/r/20221109115047.2921851-4-senozhatsky@chromium.org


Signed-off-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 001d9273

drivers/block/zram/zram_drv.c

+49 −23
Original line number Diff line number Diff line
@@ -1336,8 +1336,29 @@ static void zram_free_page(struct zram *zram, size_t index) 
		~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));

}



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

				struct bio *bio, bool partial_io)

/*

 * Reads a page from the writeback devices. Corresponding ZRAM slot

 * should be unlocked.

 */

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

				    u32 index, struct bio *bio, bool partial_io)

{

	struct bio_vec bvec = {

		.bv_page = page,

		.bv_len = PAGE_SIZE,

		.bv_offset = 0,

	};



	return read_from_bdev(zram, &bvec, zram_get_element(zram, index), bio,

			      partial_io);

}



/*

 * 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)

{

	struct zcomp_strm *zstrm;

	unsigned long handle;
@@ -1345,23 +1366,6 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, 
	void *src, *dst;

	int ret;



	zram_slot_lock(zram, index);

	if (zram_test_flag(zram, index, ZRAM_WB)) {

		struct bio_vec bvec;



		zram_slot_unlock(zram, index);

		/* A null bio means rw_page was used, we must fallback to bio */

		if (!bio)

			return -EOPNOTSUPP;



		bvec.bv_page = page;

		bvec.bv_len = PAGE_SIZE;

		bvec.bv_offset = 0;

		return read_from_bdev(zram, &bvec,

				zram_get_element(zram, index),

				bio, partial_io);

	}



	handle = zram_get_handle(zram, index);

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

		unsigned long value;
@@ -1371,7 +1375,6 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, 
		mem = kmap_atomic(page);

		zram_fill_page(mem, PAGE_SIZE, value);

		kunmap_atomic(mem);

		zram_slot_unlock(zram, index);

		return 0;

	}
@@ -1393,10 +1396,33 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, 
		zcomp_stream_put(zram->comps[ZRAM_PRIMARY_COMP]);

	}

	zs_unmap_object(zram->mem_pool, handle);

	return ret;

}



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

			    struct bio *bio, bool partial_io)

{

	int ret;



	zram_slot_lock(zram, index);

	if (!zram_test_flag(zram, index, ZRAM_WB)) {

		/* Slot should be locked through out the function call */

		ret = zram_read_from_zspool(zram, page, index);

		zram_slot_unlock(zram, index);

	} else {

		/* Slot should be unlocked before the function call */

		zram_slot_unlock(zram, index);



		/* A null bio means rw_page was used, we must fallback to bio */

		if (!bio)

			return -EOPNOTSUPP;



		ret = zram_bvec_read_from_bdev(zram, page, index, bio,

					       partial_io);

	}



	/* Should NEVER happen. Return bio error if it does. */

	if (WARN_ON(ret))

	if (WARN_ON(ret < 0))

		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);



	return ret;