linux-kernel - [PATCH 1/3] befs: remove off argument of befs_read

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Date:	Tue, 12 Jul 2016 00:02:48 +0100
From:	Luis de Bethencourt <luisbg@....samsung.com>
To:	linux-kernel@...r.kernel.org
Cc:	akpm@...ux-foundation.org, viro@...iv.linux.org.uk,
	salah.triki@...il.com, Luis de Bethencourt <luisbg@....samsung.com>
Subject: [PATCH 1/3] befs: remove off argument of befs_read_datastream

befs_read_datastream() is used to read the inode from the disk, off is
meant to provide the offset of the data in the buffer head. But the only
function using this argument already knows the starting offset of the node,
so this argument isn't needed.

Signed-off-by: Luis de Bethencourt <luisbg@....samsung.com>
---
Hi,

I know we are in release candidate 7 and maintainers are busy with important
bugs and regressions. Just sending this now so it is in the queue when the
merge window opens in two weeks.

befs_bt_read_node() is the only case where befs_read_datastream() was called
with an off pointer, the rest had NULL.

befs_read_datastream() effectively did:
block = pos >> BEFS_SB(sb)->block_shift;
*off = pos - (block << BEFS_SB(sb)->block_shift);

Since we only use it for inodes, pos above is either 0 or 1204, the node size
in BeFS by design. That shifted makes block equal 0. So off always ends up
being the same as pos. We can use this directly in befs_bt_read_node().

Thank for the reviews,
Luis

 fs/befs/btree.c      |  8 +++-----
 fs/befs/datastream.c | 10 +++-------
 fs/befs/datastream.h |  2 +-
 3 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/fs/befs/btree.c b/fs/befs/btree.c
index 307645f9..3995d58 100644
--- a/fs/befs/btree.c
+++ b/fs/befs/btree.c
@@ -142,7 +142,7 @@ befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,
 
 	befs_debug(sb, "---> %s", __func__);
 
-	bh = befs_read_datastream(sb, ds, 0, NULL);
+	bh = befs_read_datastream(sb, ds, 0);
 
 	if (!bh) {
 		befs_error(sb, "Couldn't read index header.");
@@ -196,14 +196,12 @@ static int
 befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
 		  struct befs_btree_node *node, befs_off_t node_off)
 {
-	uint off = 0;
-
 	befs_debug(sb, "---> %s", __func__);
 
 	if (node->bh)
 		brelse(node->bh);
 
-	node->bh = befs_read_datastream(sb, ds, node_off, &off);
+	node->bh = befs_read_datastream(sb, ds, node_off);
 	if (!node->bh) {
 		befs_error(sb, "%s failed to read "
 			   "node at %llu", __func__, node_off);
@@ -212,7 +210,7 @@ befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
 		return BEFS_ERR;
 	}
 	node->od_node =
-	    (befs_btree_nodehead *) ((void *) node->bh->b_data + off);
+	    (befs_btree_nodehead *) ((void *) node->bh->b_data + node_off);
 
 	befs_dump_index_node(sb, node->od_node);
 
diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c
index 26cc417..3c14c84 100644
--- a/fs/befs/datastream.c
+++ b/fs/befs/datastream.c
@@ -39,14 +39,12 @@ static int befs_find_brun_dblindirect(struct super_block *sb,
  * @sb: Filesystem superblock
  * @ds: datastrem to find data with
  * @pos: start of data
- * @off: offset of data in buffer_head->b_data
  *
- * Returns pointer to buffer_head containing data starting with offset @off,
- * if you don't need to know offset just set @off = NULL.
+ * Returns pointer to buffer_head containing data starting from pos.
  */
 struct buffer_head *
 befs_read_datastream(struct super_block *sb, const befs_data_stream *ds,
-		     befs_off_t pos, uint * off)
+		     befs_off_t pos)
 {
 	struct buffer_head *bh;
 	befs_block_run run;
@@ -54,8 +52,6 @@ befs_read_datastream(struct super_block *sb, const befs_data_stream *ds,
 
 	befs_debug(sb, "---> %s %llu", __func__, pos);
 	block = pos >> BEFS_SB(sb)->block_shift;
-	if (off)
-		*off = pos - (block << BEFS_SB(sb)->block_shift);
 
 	if (befs_fblock2brun(sb, ds, block, &run) != BEFS_OK) {
 		befs_error(sb, "BeFS: Error finding disk addr of block %lu",
@@ -131,7 +127,7 @@ befs_read_lsymlink(struct super_block *sb, const befs_data_stream *ds,
 	befs_debug(sb, "---> %s length: %llu", __func__, len);
 
 	while (bytes_read < len) {
-		bh = befs_read_datastream(sb, ds, bytes_read, NULL);
+		bh = befs_read_datastream(sb, ds, bytes_read);
 		if (!bh) {
 			befs_error(sb, "BeFS: Error reading datastream block "
 				   "starting from %llu", bytes_read);
diff --git a/fs/befs/datastream.h b/fs/befs/datastream.h
index 91ba820..76e1ab5 100644
--- a/fs/befs/datastream.h
+++ b/fs/befs/datastream.h
@@ -5,7 +5,7 @@
 
 struct buffer_head *befs_read_datastream(struct super_block *sb,
 					 const befs_data_stream *ds,
-					 befs_off_t pos, uint * off);
+					 befs_off_t pos);
 
 int befs_fblock2brun(struct super_block *sb, const befs_data_stream *data,
 		     befs_blocknr_t fblock, befs_block_run * run);
-- 
2.5.3