1 files changed, 80 insertions, 115 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 55e762a58eb6..d9c6d1fbb6dd 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -52,8 +52,8 @@
 #include "internal.h"
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
-static int submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
-			 struct writeback_control *wbc);
+static void submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
+			  struct writeback_control *wbc);
 
 #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
 
@@ -152,7 +152,7 @@ static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate)
 
 /*
  * Default synchronous end-of-IO handler..  Just mark it up-to-date and
- * unlock the buffer. This is what ll_rw_block uses too.
+ * unlock the buffer.
  */
 void end_buffer_read_sync(struct buffer_head *bh, int uptodate)
 {
@@ -491,8 +491,8 @@ int inode_has_buffers(struct inode *inode)
  * all already-submitted IO to complete, but does not queue any new
  * writes to the disk.
  *
- * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as
- * you dirty the buffers, and then use osync_inode_buffers to wait for
+ * To do O_SYNC writes, just queue the buffer writes with write_dirty_buffer
+ * as you dirty the buffers, and then use osync_inode_buffers to wait for
  * completion.  Any other dirty buffers which are not yet queued for
  * write will not be flushed to disk by the osync.
  */
@@ -562,7 +562,7 @@ void write_boundary_block(struct block_device *bdev,
 	struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize);
 	if (bh) {
 		if (buffer_dirty(bh))
-			ll_rw_block(REQ_OP_WRITE, 1, &bh);
+			write_dirty_buffer(bh, 0);
 		put_bh(bh);
 	}
 }
@@ -1342,23 +1342,12 @@ void __breadahead(struct block_device *bdev, sector_t block, unsigned size)
 {
 	struct buffer_head *bh = __getblk(bdev, block, size);
 	if (likely(bh)) {
-		ll_rw_block(REQ_OP_READ | REQ_RAHEAD, 1, &bh);
+		bh_readahead(bh, REQ_RAHEAD);
 		brelse(bh);
 	}
 }
 EXPORT_SYMBOL(__breadahead);
 
-void __breadahead_gfp(struct block_device *bdev, sector_t block, unsigned size,
-		      gfp_t gfp)
-{
-	struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp);
-	if (likely(bh)) {
-		ll_rw_block(REQ_OP_READ | REQ_RAHEAD, 1, &bh);
-		brelse(bh);
-	}
-}
-EXPORT_SYMBOL(__breadahead_gfp);
-
 /**
  *  __bread_gfp() - reads a specified block and returns the bh
  *  @bdev: the block_device to read from
@@ -1464,19 +1453,15 @@ EXPORT_SYMBOL(set_bh_page);
 
 static void discard_buffer(struct buffer_head * bh)
 {
-	unsigned long b_state, b_state_old;
+	unsigned long b_state;
 
 	lock_buffer(bh);
 	clear_buffer_dirty(bh);
 	bh->b_bdev = NULL;
-	b_state = bh->b_state;
-	for (;;) {
-		b_state_old = cmpxchg(&bh->b_state, b_state,
-				      (b_state & ~BUFFER_FLAGS_DISCARD));
-		if (b_state_old == b_state)
-			break;
-		b_state = b_state_old;
-	}
+	b_state = READ_ONCE(bh->b_state);
+	do {
+	} while (!try_cmpxchg(&bh->b_state, &b_state,
+			      b_state & ~BUFFER_FLAGS_DISCARD));
 	unlock_buffer(bh);
 }
 
@@ -1817,7 +1802,7 @@ done:
 		/*
 		 * The page was marked dirty, but the buffers were
 		 * clean.  Someone wrote them back by hand with
-		 * ll_rw_block/submit_bh.  A rare case.
+		 * write_dirty_buffer/submit_bh.  A rare case.
 		 */
 		end_page_writeback(page);
 
@@ -2033,7 +2018,7 @@ int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,
 		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
 		    !buffer_unwritten(bh) &&
 		     (block_start < from || block_end > to)) {
-			ll_rw_block(REQ_OP_READ, 1, &bh);
+			bh_read_nowait(bh, 0);
 			*wait_bh++=bh;
 		}
 	}
@@ -2352,7 +2337,7 @@ int generic_cont_expand_simple(struct inode *inode, loff_t size)
 	struct address_space *mapping = inode->i_mapping;
 	const struct address_space_operations *aops = mapping->a_ops;
 	struct page *page;
-	void *fsdata;
+	void *fsdata = NULL;
 	int err;
 
 	err = inode_newsize_ok(inode, size);
@@ -2378,7 +2363,7 @@ static int cont_expand_zero(struct file *file, struct address_space *mapping,
 	const struct address_space_operations *aops = mapping->a_ops;
 	unsigned int blocksize = i_blocksize(inode);
 	struct page *page;
-	void *fsdata;
+	void *fsdata = NULL;
 	pgoff_t index, curidx;
 	loff_t curpos;
 	unsigned zerofrom, offset, len;
@@ -2593,11 +2578,9 @@ int block_truncate_page(struct address_space *mapping,
 		set_buffer_uptodate(bh);
 
 	if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) {
-		err = -EIO;
-		ll_rw_block(REQ_OP_READ, 1, &bh);
-		wait_on_buffer(bh);
+		err = bh_read(bh, 0);
 		/* Uhhuh. Read error. Complain and punt. */
-		if (!buffer_uptodate(bh))
+		if (err < 0)
 			goto unlock;
 	}
 
@@ -2673,8 +2656,8 @@ static void end_bio_bh_io_sync(struct bio *bio)
 	bio_put(bio);
 }
 
-static int submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
-			 struct writeback_control *wbc)
+static void submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
+			  struct writeback_control *wbc)
 {
 	const enum req_op op = opf & REQ_OP_MASK;
 	struct bio *bio;
@@ -2717,70 +2700,14 @@ static int submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
 	}
 
 	submit_bio(bio);
-	return 0;
 }
 
-int submit_bh(blk_opf_t opf, struct buffer_head *bh)
+void submit_bh(blk_opf_t opf, struct buffer_head *bh)
 {
-	return submit_bh_wbc(opf, bh, NULL);
+	submit_bh_wbc(opf, bh, NULL);
 }
 EXPORT_SYMBOL(submit_bh);
 
-/**
- * ll_rw_block: low-level access to block devices (DEPRECATED)
- * @opf: block layer request operation and flags.
- * @nr: number of &struct buffer_heads in the array
- * @bhs: array of pointers to &struct buffer_head
- *
- * ll_rw_block() takes an array of pointers to &struct buffer_heads, and
- * requests an I/O operation on them, either a %REQ_OP_READ or a %REQ_OP_WRITE.
- * @opf contains flags modifying the detailed I/O behavior, most notably
- * %REQ_RAHEAD.
- *
- * This function drops any buffer that it cannot get a lock on (with the
- * BH_Lock state bit), any buffer that appears to be clean when doing a write
- * request, and any buffer that appears to be up-to-date when doing read
- * request.  Further it marks as clean buffers that are processed for
- * writing (the buffer cache won't assume that they are actually clean
- * until the buffer gets unlocked).
- *
- * ll_rw_block sets b_end_io to simple completion handler that marks
- * the buffer up-to-date (if appropriate), unlocks the buffer and wakes
- * any waiters. 
- *
- * All of the buffers must be for the same device, and must also be a
- * multiple of the current approved size for the device.
- */
-void ll_rw_block(const blk_opf_t opf, int nr, struct buffer_head *bhs[])
-{
-	const enum req_op op = opf & REQ_OP_MASK;
-	int i;
-
-	for (i = 0; i < nr; i++) {
-		struct buffer_head *bh = bhs[i];
-
-		if (!trylock_buffer(bh))
-			continue;
-		if (op == REQ_OP_WRITE) {
-			if (test_clear_buffer_dirty(bh)) {
-				bh->b_end_io = end_buffer_write_sync;
-				get_bh(bh);
-				submit_bh(opf, bh);
-				continue;
-			}
-		} else {
-			if (!buffer_uptodate(bh)) {
-				bh->b_end_io = end_buffer_read_sync;
-				get_bh(bh);
-				submit_bh(opf, bh);
-				continue;
-			}
-		}
-		unlock_buffer(bh);
-	}
-}
-EXPORT_SYMBOL(ll_rw_block);
-
 void write_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags)
 {
 	lock_buffer(bh);
@@ -2801,8 +2728,6 @@ EXPORT_SYMBOL(write_dirty_buffer);
  */
 int __sync_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags)
 {
-	int ret = 0;
-
 	WARN_ON(atomic_read(&bh->b_count) < 1);
 	lock_buffer(bh);
 	if (test_clear_buffer_dirty(bh)) {
@@ -2817,14 +2742,14 @@ int __sync_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags)
 
 		get_bh(bh);
 		bh->b_end_io = end_buffer_write_sync;
-		ret = submit_bh(REQ_OP_WRITE | op_flags, bh);
+		submit_bh(REQ_OP_WRITE | op_flags, bh);
 		wait_on_buffer(bh);
-		if (!ret && !buffer_uptodate(bh))
-			ret = -EIO;
+		if (!buffer_uptodate(bh))
+			return -EIO;
 	} else {
 		unlock_buffer(bh);
 	}
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(__sync_dirty_buffer);
 
@@ -3029,29 +2954,69 @@ int bh_uptodate_or_lock(struct buffer_head *bh)
 EXPORT_SYMBOL(bh_uptodate_or_lock);
 
 /**
- * bh_submit_read - Submit a locked buffer for reading
+ * __bh_read - Submit read for a locked buffer
  * @bh: struct buffer_head
+ * @op_flags: appending REQ_OP_* flags besides REQ_OP_READ
+ * @wait: wait until reading finish
  *
- * Returns zero on success and -EIO on error.
+ * Returns zero on success or don't wait, and -EIO on error.
  */
-int bh_submit_read(struct buffer_head *bh)
+int __bh_read(struct buffer_head *bh, blk_opf_t op_flags, bool wait)
 {
-	BUG_ON(!buffer_locked(bh));
+	int ret = 0;
 
-	if (buffer_uptodate(bh)) {
-		unlock_buffer(bh);
-		return 0;
-	}
+	BUG_ON(!buffer_locked(bh));
 
 	get_bh(bh);
 	bh->b_end_io = end_buffer_read_sync;
-	submit_bh(REQ_OP_READ, bh);
-	wait_on_buffer(bh);
-	if (buffer_uptodate(bh))
-		return 0;
-	return -EIO;
+	submit_bh(REQ_OP_READ | op_flags, bh);
+	if (wait) {
+		wait_on_buffer(bh);
+		if (!buffer_uptodate(bh))
+			ret = -EIO;
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__bh_read);
+
+/**
+ * __bh_read_batch - Submit read for a batch of unlocked buffers
+ * @nr: entry number of the buffer batch
+ * @bhs: a batch of struct buffer_head
+ * @op_flags: appending REQ_OP_* flags besides REQ_OP_READ
+ * @force_lock: force to get a lock on the buffer if set, otherwise drops any
+ *              buffer that cannot lock.
+ *
+ * Returns zero on success or don't wait, and -EIO on error.
+ */
+void __bh_read_batch(int nr, struct buffer_head *bhs[],
+		     blk_opf_t op_flags, bool force_lock)
+{
+	int i;
+
+	for (i = 0; i < nr; i++) {
+		struct buffer_head *bh = bhs[i];
+
+		if (buffer_uptodate(bh))
+			continue;
+
+		if (force_lock)
+			lock_buffer(bh);
+		else
+			if (!trylock_buffer(bh))
+				continue;
+
+		if (buffer_uptodate(bh)) {
+			unlock_buffer(bh);
+			continue;
+		}
+
+		bh->b_end_io = end_buffer_read_sync;
+		get_bh(bh);
+		submit_bh(REQ_OP_READ | op_flags, bh);
+	}
 }
-EXPORT_SYMBOL(bh_submit_read);
+EXPORT_SYMBOL(__bh_read_batch);
 
 void __init buffer_init(void)
 {