ext4: use proper little-endian bitops

PATCH New Akinobu Mita 1 participant 1 message Jun 2, 2011 ext4 file system

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Akinobu Mita

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2011-06-02 15:51 UTC #0 lore raw

PATCH v3 1/1 ext4: use proper little-endian bitops

ext4_{set,clear}_bit() is defined as __test_and_{set,clear}_bit_le() for ext4. Only two ext4_{set,clear}_bit() calls check the return value. The rest of calls ignore the return value and they can be replaced with __{set,clear}_bit_le().

This changes ext4_{set,clear}_bit() from __test_and_{set,clear}_bit_le() to __{set,clear}_bit_le() and introduces ext4_test_and_{set,clear}_bit() for the two places where old bit needs to be returned.

This ext4_{set,clear}_bit() change is considered safe, because if someone uses these macros without noticing the change, new ext4_{set,clear}_bit don't have return value and causes compiler errors where the return value is used.

This also removes unused ext4_find_first_zero_bit().

Signed-off-by Akinobu Mita <[email protected]>

Cc "Theodore Ts'o" <[email protected]>

Cc Andreas Dilger <[email protected]>

Cc [email protected]

---
v3: squash into a single patch and do not remove ext4_*_bit_atomic() macros
v2: rewritten to keep ext4_*_bit() macros

 fs/ext4/ext4.h   |    7 ++++---
 fs/ext4/ialloc.c |    4 ++--
 2 files changed, 6 insertions(+), 5 deletions(-)

fs/ext4/ext4.h +4 -3

index 1921392..cb65177 100644
@@ -930,12 +930,13 @@ struct ext4_inode_info {
 #define test_opt2(sb, opt)		(EXT4_SB(sb)->s_mount_opt2 & \
 					 EXT4_MOUNT2_##opt)
 
-#define ext4_set_bit			__test_and_set_bit_le
+#define ext4_test_and_set_bit		__test_and_set_bit_le
+#define ext4_set_bit			__set_bit_le
 #define ext4_set_bit_atomic		ext2_set_bit_atomic
-#define ext4_clear_bit			__test_and_clear_bit_le
+#define ext4_test_and_clear_bit		__test_and_clear_bit_le
+#define ext4_clear_bit			__clear_bit_le
 #define ext4_clear_bit_atomic		ext2_clear_bit_atomic
 #define ext4_test_bit			test_bit_le
-#define ext4_find_first_zero_bit	find_first_zero_bit_le
 #define ext4_find_next_zero_bit		find_next_zero_bit_le
 #define ext4_find_next_bit		find_next_bit_le

fs/ext4/ialloc.c +2 -2

index 21bb2f6..e3de479 100644
@@ -252,7 +252,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 		fatal = ext4_journal_get_write_access(handle, bh2);
 	}
 	ext4_lock_group(sb, block_group);
-	cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
+	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 	if (fatal || !cleared) {
 		ext4_unlock_group(sb, block_group);
 		goto out;

@@ -729,7 +729,7 @@ static int ext4_claim_inode(struct super_block *sb,
 	 */
 	down_read(&grp->alloc_sem);
 	ext4_lock_group(sb, group);
-	if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
+	if (ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data)) {
 		/* not a free inode */
 		retval = 1;
 		goto err_ret;

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