zram: do not pass rw argument to __zram_make_request()

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).

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit be257c61306750d11c20d2ac567bf63304c696a3)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
 Conflicts:
	drivers/block/zram/zram_drv.c

 Conflicts solution:
	keep bio struct as old before commit 4f024f3797
		'block: Abstract out bvec iterator'

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e75ccdf194a63b2e51b4a241d7285792a3d0ce06..3f98cf21c7f09027a64fb9cbde687c2f8725c514 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -532,14 +532,18 @@ 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;
 }
@@ -671,20 +675,12 @@ 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 i, offset;
        u32 index;
        struct bio_vec *bvec;
 
-       switch (rw) {
-       case READ:
-               atomic64_inc(&zram->stats.num_reads);
-               break;
-       case WRITE:
-               atomic64_inc(&zram->stats.num_writes);
-               break;
-       }
 
        index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
        offset = (bio->bi_sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
@@ -703,16 +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);
@@ -742,7 +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;