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Date: Mon, 18 Nov 2013 18:12:02 +0900
From: Jaegeuk Kim <jaegeuk.kim@...sung.com>
To: unlisted-recipients:; (no To-header on input)
Cc: Jaegeuk Kim <jaegeuk.kim@...sung.com>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH 2/2] f2fs: use sbi->wr_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.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@...sung.com>
---
fs/f2fs/data.c | 4 ----
fs/f2fs/f2fs.h | 2 +-
fs/f2fs/segment.c | 13 +++++++++----
fs/f2fs/super.c | 2 +-
4 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 84867dc..7550026 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -390,8 +390,6 @@ 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);
@@ -401,13 +399,11 @@ 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;
}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1c783fd..76f5586 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -375,7 +375,7 @@ 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; /* mutex for writing IOs */
/* for checkpoint */
struct f2fs_checkpoint *ckpt; /* raw checkpoint pointer */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index dad5f1a..893d489 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -871,9 +871,14 @@ 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);
do_submit_bio(sbi, type, sync);
- up_write(&sbi->bio_sem);
+ mutex_unlock(&sbi->write_mutex);
}
static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page,
@@ -884,7 +889,7 @@ 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);
inc_page_count(sbi, F2FS_WRITEBACK);
@@ -919,7 +924,7 @@ retry:
sbi->last_block_in_bio[type] = blk_addr;
- up_write(&sbi->bio_sem);
+ mutex_unlock(&sbi->write_mutex);
trace_f2fs_submit_write_page(page, blk_addr, type);
}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 2c52527..c7b6300 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -882,7 +882,7 @@ 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);
+ mutex_init(&sbi->write_mutex);
init_rwsem(&sbi->cp_rwsem);
init_waitqueue_head(&sbi->cp_wait);
init_sb_info(sbi);
--
1.8.4.474.g128a96c
--
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