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Commit b53858b8 authored by Minchan Kim's avatar Minchan Kim Committed by Peter Kalauskas
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UPSTREAM: zram: identify asynchronous IO's return value 

For upcoming asynchronous IO like writeback, zram_rw_page should be
aware of that whether requested IO was completed or submitted
successfully, otherwise error.

For the goal, zram_bvec_rw has three return values.

-errno: returns error number
     0: IO request is done synchronously
     1: IO request is issued successfully.

Link: http://lkml.kernel.org/r/1498459987-24562-7-git-send-email-minchan@kernel.org


Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
Cc: Juneho Choi <juno.choi@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit ae85a8075c5b025b9d503554ddc480a346a24536)
Signed-off-by: default avatarPeter Kalauskas <peskal@google.com>
Bug: 112488418
Change-Id: I5db9076b60456a33a702152882472014bee755bb
parent 0e05f38f

drivers/block/zram/zram_drv.c

+24 −8
Original line number Diff line number Diff line
@@ -779,7 +779,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, 


static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)

{

	int ret;

	int ret = 0;

	unsigned long alloced_pages;

	unsigned long handle = 0;

	unsigned int comp_len = 0;
@@ -884,7 +884,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index) 


	/* Update stats */

	atomic64_inc(&zram->stats.pages_stored);

	return 0;

	return ret;

}



static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
@@ -966,6 +966,11 @@ static void zram_bio_discard(struct zram *zram, u32 index, 
	}

}



/*

 * Returns errno if it has some problem. Otherwise return 0 or 1.

 * Returns 0 if IO request was done synchronously

 * Returns 1 if IO request was successfully submitted.

 */

static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,

			int offset, bool is_write)

{
@@ -987,7 +992,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, 


	generic_end_io_acct(rw_acct, &zram->disk->part0, start_time);



	if (unlikely(ret)) {

	if (unlikely(ret < 0)) {

		if (!is_write)

			atomic64_inc(&zram->stats.failed_reads);

		else
@@ -1076,7 +1081,7 @@ static void zram_slot_free_notify(struct block_device *bdev, 
static int zram_rw_page(struct block_device *bdev, sector_t sector,

		       struct page *page, bool is_write)

{

	int offset, err = -EIO;

	int offset, ret;

	u32 index;

	struct zram *zram;

	struct bio_vec bv;
@@ -1085,7 +1090,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, 


	if (!valid_io_request(zram, sector, PAGE_SIZE)) {

		atomic64_inc(&zram->stats.invalid_io);

		err = -EINVAL;

		ret = -EINVAL;

		goto out;

	}
@@ -1096,7 +1101,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, 
	bv.bv_len = PAGE_SIZE;

	bv.bv_offset = 0;



	err = zram_bvec_rw(zram, &bv, index, offset, is_write);

	ret = zram_bvec_rw(zram, &bv, index, offset, is_write);

out:

	/*

	 * If I/O fails, just return error(ie, non-zero) without
@@ -1106,9 +1111,20 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, 
	 * bio->bi_end_io does things to handle the error

	 * (e.g., SetPageError, set_page_dirty and extra works).

	 */

	if (err == 0)

	if (unlikely(ret < 0))

		return ret;



	switch (ret) {

	case 0:

		page_endio(page, is_write, 0);

	return err;

		break;

	case 1:

		ret = 0;

		break;

	default:

		WARN_ON(1);

	}

	return ret;

}



static void zram_reset_device(struct zram *zram)