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Date: Mon, 6 Oct 2014 14:31:05 +0900
From: karam.lee@....com
To: minchan@...nel.org, ngupta@...are.org, linux-kernel@...r.kernel.org
Cc: seungho1.park@....com, karam.lee@....com
Subject: [PATCH] zram: implement rw_page operation of zram block device operation
From: "karam.lee" <karam.lee@....com>
Recently rw_page block device operation is added.
This patch implements rw_page operation for zram block device so
zram can process page sized I/O without bio.
---
---
drivers/block/zram/zram_drv.c | 60 +++++++++++++++++++++++++++++++++++------
1 file changed, 52 insertions(+), 8 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 48eccb3..b76a5dc 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -368,7 +368,7 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
}
static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
- u32 index, int offset, struct bio *bio)
+ u32 index, int offset)
{
int ret;
struct page *page;
@@ -535,14 +535,13 @@ out:
}
static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
- int offset, struct bio *bio)
+ int offset, int rw)
{
int ret;
- int rw = bio_data_dir(bio);
if (rw == READ) {
atomic64_inc(&zram->stats.num_reads);
- ret = zram_bvec_read(zram, bvec, index, offset, bio);
+ ret = zram_bvec_read(zram, bvec, index, offset);
} else {
atomic64_inc(&zram->stats.num_writes);
ret = zram_bvec_write(zram, bvec, index, offset);
@@ -718,7 +717,7 @@ out:
static void __zram_make_request(struct zram *zram, struct bio *bio)
{
- int offset;
+ int offset, rw;
u32 index;
struct bio_vec bvec;
struct bvec_iter iter;
@@ -733,6 +732,7 @@ static void __zram_make_request(struct zram *zram, struct bio *bio)
return;
}
+ rw = bio_data_dir(bio);
bio_for_each_segment(bvec, bio, iter) {
int max_transfer_size = PAGE_SIZE - offset;
@@ -747,15 +747,15 @@ static void __zram_make_request(struct zram *zram, struct bio *bio)
bv.bv_len = max_transfer_size;
bv.bv_offset = bvec.bv_offset;
- if (zram_bvec_rw(zram, &bv, index, offset, bio) < 0)
+ if (zram_bvec_rw(zram, &bv, index, offset, rw) < 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) < 0)
+ if (zram_bvec_rw(zram, &bv, index + 1, 0, rw) < 0)
goto out;
} else
- if (zram_bvec_rw(zram, &bvec, index, offset, bio) < 0)
+ if (zram_bvec_rw(zram, &bvec, index, offset, rw) < 0)
goto out;
update_position(&index, &offset, &bvec);
@@ -810,8 +810,52 @@ static void zram_slot_free_notify(struct block_device *bdev,
atomic64_inc(&zram->stats.notify_free);
}
+static int zram_rw_page(struct block_device *bdev, sector_t sector,
+ struct page *page, int rw)
+{
+ int offset, ret = 1;
+ u32 index;
+ u64 start, end, bound;
+ struct zram *zram;
+ struct bio_vec bv;
+
+ zram = bdev->bd_disk->private_data;
+
+ if (unlikely(sector&
+ (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
+ goto out;
+
+ start = sector;
+ end = start + (PAGE_SIZE >> SECTOR_SHIFT);
+ bound = zram->disksize >> SECTOR_SHIFT;
+ if (unlikely(start >= bound || end > bound || start > end))
+ goto out;
+
+ down_read(&zram->init_lock);
+ if (unlikely(!init_done(zram))) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ index = sector >> SECTORS_PER_PAGE_SHIFT;
+ offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT;
+
+ bv.bv_page = page;
+ bv.bv_len = PAGE_SIZE;
+ bv.bv_offset = 0;
+
+ ret = zram_bvec_rw(zram, &bv, index, offset, rw);
+ page_endio(page, rw, ret);
+
+out_unlock:
+ up_read(&zram->init_lock);
+out:
+ return ret;
+}
+
static const struct block_device_operations zram_devops = {
.swap_slot_free_notify = zram_slot_free_notify,
+ .rw_page = zram_rw_page,
.owner = THIS_MODULE
};
--
1.7.9.5
--
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