ext4: use proper little-endian bitops (597d508c) · Commits · 戴 / test

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 <akinobu.mita@gmail.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

+4 −3

Original line number	Diff line number	Diff line
		@@ -957,12 +957,13 @@ 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

Original line number	Diff line number	Diff line
		@@ -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;
		@@ -618,7 +618,7 @@ 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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