Make alloc_page_buffers support circular buffer list and initialise b_state field. Optimize the performance by removing the buffer list traversal to create circular buffer list.
Signed-off-by: Sean Fu <[email protected]> --- drivers/md/bitmap.c | 2 +- fs/buffer.c | 37 +++++++++++++++---------------------- fs/ntfs/aops.c | 2 +- fs/ntfs/mft.c | 2 +- include/linux/buffer_head.h | 2 +- 5 files changed, 19 insertions(+), 26 deletions(-) diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index f4eace5..615a46e 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -367,7 +367,7 @@ static int read_page(struct file *file, unsigned long index, pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE, (unsigned long long)index << PAGE_SHIFT); - bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0); + bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0, 0, 0); if (!bh) { ret = -ENOMEM; goto out; diff --git a/fs/buffer.c b/fs/buffer.c index 161be58..8111eca 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -864,9 +864,9 @@ int remove_inode_buffers(struct inode *inode) * which may not fail from ordinary buffer allocations. */ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, - int retry) + int retry, int circular, unsigned long b_state) { - struct buffer_head *bh, *head; + struct buffer_head *bh, *head, *tail; long offset; try_again: @@ -879,13 +879,21 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, bh->b_this_page = head; bh->b_blocknr = -1; - head = bh; + if (head == NULL) + tail = bh; + + head = bh; + bh->b_state = b_state; bh->b_size = size; /* Link the buffer to its page */ set_bh_page(bh, page, offset); } + + if (circular) + tail->b_this_page = head; + return head; /* * In case anything failed, we just free everything we got. @@ -922,14 +930,6 @@ EXPORT_SYMBOL_GPL(alloc_page_buffers); static inline void link_dev_buffers(struct page *page, struct buffer_head *head) { - struct buffer_head *bh, *tail; - - bh = head; - do { - tail = bh; - bh = bh->b_this_page; - } while (bh); - tail->b_this_page = head; attach_page_buffers(page, head); } @@ -1024,7 +1024,7 @@ grow_dev_page(struct block_device *bdev, sector_t block, /* * Allocate some buffers for this page */ - bh = alloc_page_buffers(page, size, 0); + bh = alloc_page_buffers(page, size, 0, 1, 0); if (!bh) goto failed; @@ -1578,16 +1578,9 @@ EXPORT_SYMBOL(block_invalidatepage); void create_empty_buffers(struct page *page, unsigned long blocksize, unsigned long b_state) { - struct buffer_head *bh, *head, *tail; + struct buffer_head *bh, *head; - head = alloc_page_buffers(page, blocksize, 1); - bh = head; - do { - bh->b_state |= b_state; - tail = bh; - bh = bh->b_this_page; - } while (bh); - tail->b_this_page = head; + head = alloc_page_buffers(page, blocksize, 1, 1, b_state); spin_lock(&page->mapping->private_lock); if (PageUptodate(page) || PageDirty(page)) { @@ -2642,7 +2635,7 @@ int nobh_write_begin(struct address_space *mapping, * Be careful: the buffer linked list is a NULL terminated one, rather * than the circular one we're used to. */ - head = alloc_page_buffers(page, blocksize, 0); + head = alloc_page_buffers(page, blocksize, 0, 0, 0); if (!head) { ret = -ENOMEM; goto out_release; diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c index cc91856..e692142 100644 --- a/fs/ntfs/aops.c +++ b/fs/ntfs/aops.c @@ -1739,7 +1739,7 @@ void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) { spin_lock(&mapping->private_lock); if (unlikely(!page_has_buffers(page))) { spin_unlock(&mapping->private_lock); - bh = head = alloc_page_buffers(page, bh_size, 1); + bh = head = alloc_page_buffers(page, bh_size, 1, 0, 0); spin_lock(&mapping->private_lock); if (likely(!page_has_buffers(page))) { struct buffer_head *tail; diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c index b6f4021..175a02b 100644 --- a/fs/ntfs/mft.c +++ b/fs/ntfs/mft.c @@ -507,7 +507,7 @@ int ntfs_sync_mft_mirror(ntfs_volume *vol, const unsigned long mft_no, if (unlikely(!page_has_buffers(page))) { struct buffer_head *tail; - bh = head = alloc_page_buffers(page, blocksize, 1); + bh = head = alloc_page_buffers(page, blocksize, 1, 0, 0); do { set_buffer_uptodate(bh); tail = bh; diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index bd029e52..9a29826 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -155,7 +155,7 @@ void set_bh_page(struct buffer_head *bh, struct page *page, unsigned long offset); int try_to_free_buffers(struct page *); struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, - int retry); + int retry, int circular, unsigned long b_state); void create_empty_buffers(struct page *, unsigned long, unsigned long b_state); void end_buffer_read_sync(struct buffer_head *bh, int uptodate); -- 2.6.2
