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Commit 971767ca authored by Jaegeuk Kim's avatar Jaegeuk Kim
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f2fs: use sbi->write_mutex for write bios 



This patch removes an unnecessary semaphore (i.e., sbi->bio_sem).
There is no reason to use the semaphore when f2fs submits read and write IOs.
Instead, let's use a write mutex and cover the sbi->bio[] by the lock.

Change log from v1:
 o split write_mutex suggested by Chao Yu

Chao described,
"All DATA/NODE/META bio buffers in superblock is protected by
'sbi->write_mutex', but each bio buffer area is independent, So we
should split write_mutex to three for DATA/NODE/META."

Signed-off-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent 7d5e5109

fs/f2fs/data.c

+0 −4
Original line number Diff line number Diff line
@@ -383,8 +383,6 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page, 


	trace_f2fs_readpage(page, blk_addr, type);



	down_read(&sbi->bio_sem);



	/* Allocate a new bio */

	bio = f2fs_bio_alloc(bdev, 1);
@@ -394,13 +392,11 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page, 


	if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {

		bio_put(bio);

		up_read(&sbi->bio_sem);

		f2fs_put_page(page, 1);

		return -EFAULT;

	}



	submit_bio(type, bio);

	up_read(&sbi->bio_sem);

	return 0;

}

fs/f2fs/f2fs.h

+1 −1
Original line number Diff line number Diff line
@@ -374,7 +374,7 @@ struct f2fs_sb_info { 
	struct f2fs_sm_info *sm_info;		/* segment manager */

	struct bio *bio[NR_PAGE_TYPE];		/* bios to merge */

	sector_t last_block_in_bio[NR_PAGE_TYPE];	/* last block number */

	struct rw_semaphore bio_sem;		/* IO semaphore */

	struct mutex write_mutex[NR_PAGE_TYPE];	/* mutex for writing IOs */



	/* for checkpoint */

	struct f2fs_checkpoint *ckpt;		/* raw checkpoint pointer */

fs/f2fs/segment.c

+9 −4
Original line number Diff line number Diff line
@@ -869,9 +869,14 @@ static void do_submit_bio(struct f2fs_sb_info *sbi, 


void f2fs_submit_bio(struct f2fs_sb_info *sbi, enum page_type type, bool sync)

{

	down_write(&sbi->bio_sem);

	enum page_type btype = PAGE_TYPE_OF_BIO(type);



	if (!sbi->bio[btype])

		return;



	mutex_lock(&sbi->write_mutex[btype]);

	do_submit_bio(sbi, type, sync);

	up_write(&sbi->bio_sem);

	mutex_unlock(&sbi->write_mutex[btype]);

}



static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page,
@@ -882,7 +887,7 @@ static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page, 


	verify_block_addr(sbi, blk_addr);



	down_write(&sbi->bio_sem);

	mutex_lock(&sbi->write_mutex[type]);



	inc_page_count(sbi, F2FS_WRITEBACK);
@@ -917,7 +922,7 @@ static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page, 


	sbi->last_block_in_bio[type] = blk_addr;



	up_write(&sbi->bio_sem);

	mutex_unlock(&sbi->write_mutex[type]);

	trace_f2fs_submit_write_page(page, blk_addr, type);

}

fs/f2fs/super.c

+5 −1
Original line number Diff line number Diff line
@@ -820,6 +820,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) 
	struct buffer_head *raw_super_buf;

	struct inode *root;

	long err = -EINVAL;

	int i;



	/* allocate memory for f2fs-specific super block info */

	sbi = kzalloc(sizeof(struct f2fs_sb_info), GFP_KERNEL);
@@ -876,7 +877,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) 
	mutex_init(&sbi->node_write);

	sbi->por_doing = false;

	spin_lock_init(&sbi->stat_lock);

	init_rwsem(&sbi->bio_sem);



	for (i = 0; i < NR_PAGE_TYPE; i++)

		mutex_init(&sbi->write_mutex[i]);



	init_rwsem(&sbi->cp_rwsem);

	init_waitqueue_head(&sbi->cp_wait);

	init_sb_info(sbi);