[PATCHv3 2/8] zram: do not pass rw argument to __zram_make_request()

Sergey Senozhatsky
2014-01-16T13:15:47Z

Do not pass rw argument down the __zram_make_request() -> zram_bvec_rw()
chain, decode it in zram_bvec_rw() instead. Besides, this is the place
where we distinguish READ and WRITE bio data directions, so account zram
RW stats here, instead of __zram_make_request(). This also allows to account
a real number of zram READ/WRITE operations, not just requests (single RW
request may cause a number of zram RW ops with separate locking,
compression/decompression, etc).

v2: do not check for READA return code. noted by Jerome Marchand.

Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
drivers/block/zram/zram_drv.c | 30 ++++++++++++------------------
1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c323e05..b0bcb7e 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -533,14 +533,18 @@ out:
}

static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
- int offset, struct bio *bio, int rw)
+ int offset, struct bio *bio)
{
int ret;
+ int rw = bio_data_dir(bio);

- if (rw == READ)
+ if (rw == READ) {
+ atomic64_inc(&zram->stats.num_reads);
ret = zram_bvec_read(zram, bvec, index, offset, bio);
- else
+ } else {
+ atomic64_inc(&zram->stats.num_writes);
ret = zram_bvec_write(zram, bvec, index, offset);
+ }

return ret;
}
@@ -670,22 +674,13 @@ out:
return ret;
}

-static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
+static void __zram_make_request(struct zram *zram, struct bio *bio)
{
int offset;
u32 index;
struct bio_vec bvec;
struct bvec_iter iter;

- switch (rw) {
- case READ:
- atomic64_inc(&zram->stats.num_reads);
- break;
- case WRITE:
- atomic64_inc(&zram->stats.num_writes);
- break;
- }
-
index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
offset = (bio->bi_iter.bi_sector &
(SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
@@ -704,16 +699,15 @@ static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
bv.bv_len = max_transfer_size;
bv.bv_offset = bvec.bv_offset;

- if (zram_bvec_rw(zram, &bv, index, offset, bio, rw) < 0)
+ if (zram_bvec_rw(zram, &bv, index, offset, bio) < 0)
goto out;

bv.bv_len = bvec.bv_len - max_transfer_size;
bv.bv_offset += max_transfer_size;
- if (zram_bvec_rw(zram, &bv, index+1, 0, bio, rw) < 0)
+ if (zram_bvec_rw(zram, &bv, index + 1, 0, bio) < 0)
goto out;
} else
- if (zram_bvec_rw(zram, &bvec, index, offset, bio, rw)
- < 0)
+ if (zram_bvec_rw(zram, &bvec, index, offset, bio) < 0)
goto out;

update_position(&index, &offset, &bvec);
@@ -743,7 +737,7 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio)
goto error;
}

- __zram_make_request(zram, bio, bio_data_dir(bio));
+ __zram_make_request(zram, bio);
up_read(&zram->init_lock);

return;
--
1.8.5.3.493.gb139ac2