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authorChristoph Hellwig <hch@lst.de>2020-01-24 01:01:34 +0800
committerJens Axboe <axboe@kernel.dk>2020-01-23 11:40:01 -0700
commit6321bef028de43724c47cfa7f9dee69ecb783796 (patch)
tree2662f6f43b7ee040d48c2e9a049b8ab821ebae9b /drivers/md/bcache
parent475389ae5c08656f8bb5cc3adc88a531c7c4877f (diff)
bcache: use read_cache_page_gfp to read the superblock
Avoid a pointless dependency on buffer heads in bcache by simply open coding reading a single page. Also add a SB_OFFSET define for the byte offset of the superblock instead of using magic numbers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache')
-rw-r--r--drivers/md/bcache/super.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 5797c03f993e..3dea1d5acd5c 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -15,7 +15,6 @@
#include "writeback.h"
#include <linux/blkdev.h>
-#include <linux/buffer_head.h>
#include <linux/debugfs.h>
#include <linux/genhd.h>
#include <linux/idr.h>
@@ -64,13 +63,14 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
{
const char *err;
struct cache_sb_disk *s;
- struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
+ struct page *page;
unsigned int i;
- if (!bh)
+ page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
+ SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
+ if (IS_ERR(page))
return "IO error";
-
- s = (struct cache_sb_disk *)bh->b_data;
+ s = page_address(page) + offset_in_page(SB_OFFSET);
sb->offset = le64_to_cpu(s->offset);
sb->version = le64_to_cpu(s->version);
@@ -188,12 +188,10 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
}
sb->last_mount = (u32)ktime_get_real_seconds();
- err = NULL;
-
- get_page(bh->b_page);
*res = s;
+ return NULL;
err:
- put_bh(bh);
+ put_page(page);
return err;
}