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Message-Id: <46950A08-9300-4649-A38D-88829035DFC2@dilger.ca>
Date: Wed, 1 Jun 2011 14:49:18 -0600
From: Andreas Dilger <adilger.kernel@...ger.ca>
To: Akinobu Mita <akinobu.mita@...il.com>
Cc: linux-kernel@...r.kernel.org, "Theodore Ts'o" <tytso@....edu>,
linux-ext4@...r.kernel.org
Subject: Re: [PATCH v2 1/2] ext4: arrange ext4_*_bit() macros
On 2011-06-01, at 8:36 AM, Akinobu Mita wrote:
> - remove unused ext4_{set,clear}_bit_atomic and ext4_find_first_zero_bit
> - rename ext4_{set,clear}_bit to ext4_test_and_{set,clear}_bit
> - reintroduce ext4_{set,clear}_bit for __{set,clear}_bit_le
>
> This changes ext4_{set,clear}_bit safely, 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.
I don't think it makes sense to change all of the ext4_set_bit() calls that
don't check the return code to use ext4_test_and_set_bit(), just to return
them back to ext4_set_bit() in the next patch.
If you want to do this in separate steps, and maintain git bisect working,
then it would be more clear to have two patches:
Patch #1: Add new ext4_test_and_set_bit() macro
#define ext4_test_and_set_bit __test_and_set_bit_le
{change ext4_set_bit() calls that check return to ext4_test_and_set_bit()}
Patch #2: Change ext4_set_bit() to not return old bit
#define ext4_set_bit __set_bit_le
{nothing else changes}
Alternately, you could just leave the calls that do not check the return
value as ext4_set_bit() and have only a single patch.
> Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
> Cc: "Theodore Ts'o" <tytso@....edu>
> Cc: Andreas Dilger <adilger.kernel@...ger.ca>
> Cc: linux-ext4@...r.kernel.org
> ---
> v2: rewritten to keep ext4_*_bit() macros
>
> fs/ext4/balloc.c | 8 ++++----
> fs/ext4/ext4.h | 9 ++++-----
> fs/ext4/ialloc.c | 9 ++++-----
> fs/ext4/mballoc.c | 4 ++--
> fs/ext4/resize.c | 12 ++++++------
> 5 files changed, 20 insertions(+), 22 deletions(-)
>
> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
> index 264f694..b6747e4 100644
> --- a/fs/ext4/balloc.c
> +++ b/fs/ext4/balloc.c
> @@ -144,7 +144,7 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
> int flex_bg = 0;
>
> for (bit = 0; bit < bit_max; bit++)
> - ext4_set_bit(bit, bh->b_data);
> + ext4_test_and_set_bit(bit, bh->b_data);
>
> start = ext4_group_first_block_no(sb, block_group);
>
> @@ -155,18 +155,18 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
> /* Set bits for block and inode bitmaps, and inode table */
> tmp = ext4_block_bitmap(sb, gdp);
> if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
> - ext4_set_bit(tmp - start, bh->b_data);
> + ext4_test_and_set_bit(tmp - start, bh->b_data);
>
> tmp = ext4_inode_bitmap(sb, gdp);
> if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
> - ext4_set_bit(tmp - start, bh->b_data);
> + ext4_test_and_set_bit(tmp - start, bh->b_data);
>
> tmp = ext4_inode_table(sb, gdp);
> for (; tmp < ext4_inode_table(sb, gdp) +
> sbi->s_itb_per_group; tmp++) {
> if (!flex_bg ||
> ext4_block_in_group(sb, tmp, block_group))
> - ext4_set_bit(tmp - start, bh->b_data);
> + ext4_test_and_set_bit(tmp - start, bh->b_data);
> }
> /*
> * Also if the number of blocks within the group is
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 1921392..04db84f 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -930,12 +930,11 @@ 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_set_bit_atomic ext2_set_bit_atomic
> -#define ext4_clear_bit __test_and_clear_bit_le
> -#define ext4_clear_bit_atomic ext2_clear_bit_atomic
> +#define ext4_test_and_set_bit __test_and_set_bit_le
> +#define ext4_set_bit __set_bit_le
> +#define ext4_test_and_clear_bit __test_and_clear_bit_le
> +#define ext4_clear_bit __clear_bit_le
> #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
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 21bb2f6..90bef6b 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -59,7 +59,7 @@ void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
>
> ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
> for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
> - ext4_set_bit(i, bitmap);
> + ext4_test_and_set_bit(i, bitmap);
> if (i < end_bit)
> memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
> }
> @@ -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;
> @@ -884,8 +884,7 @@ got_group:
> goto fail;
>
> repeat_in_this_group:
> - ino = ext4_find_next_zero_bit((unsigned long *)
> - inode_bitmap_bh->b_data,
> + ino = ext4_find_next_zero_bit(inode_bitmap_bh->b_data,
> EXT4_INODES_PER_GROUP(sb), ino);
>
> if (ino < EXT4_INODES_PER_GROUP(sb)) {
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 859f2ae..b423adf 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -384,13 +384,13 @@ static inline int mb_test_bit(int bit, void *addr)
> static inline void mb_set_bit(int bit, void *addr)
> {
> addr = mb_correct_addr_and_bit(&bit, addr);
> - ext4_set_bit(bit, addr);
> + ext4_test_and_set_bit(bit, addr);
> }
>
> static inline void mb_clear_bit(int bit, void *addr)
> {
> addr = mb_correct_addr_and_bit(&bit, addr);
> - ext4_clear_bit(bit, addr);
> + ext4_test_and_clear_bit(bit, addr);
> }
>
> static inline int mb_find_next_zero_bit(void *addr, int max, int start)
> diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
> index 80bbc9c..cc40963 100644
> --- a/fs/ext4/resize.c
> +++ b/fs/ext4/resize.c
> @@ -194,7 +194,7 @@ static int setup_new_group_blocks(struct super_block *sb,
>
> if (ext4_bg_has_super(sb, input->group)) {
> ext4_debug("mark backup superblock %#04llx (+0)\n", start);
> - ext4_set_bit(0, bh->b_data);
> + ext4_test_and_set_bit(0, bh->b_data);
> }
>
> /* Copy all of the GDT blocks into the backup in this group */
> @@ -225,7 +225,7 @@ static int setup_new_group_blocks(struct super_block *sb,
> brelse(gdb);
> goto exit_bh;
> }
> - ext4_set_bit(bit, bh->b_data);
> + ext4_test_and_set_bit(bit, bh->b_data);
> brelse(gdb);
> }
>
> @@ -237,14 +237,14 @@ static int setup_new_group_blocks(struct super_block *sb,
> if (err)
> goto exit_bh;
> for (i = 0, bit = gdblocks + 1; i < reserved_gdb; i++, bit++)
> - ext4_set_bit(bit, bh->b_data);
> + ext4_test_and_set_bit(bit, bh->b_data);
>
> ext4_debug("mark block bitmap %#04llx (+%llu)\n", input->block_bitmap,
> input->block_bitmap - start);
> - ext4_set_bit(input->block_bitmap - start, bh->b_data);
> + ext4_test_and_set_bit(input->block_bitmap - start, bh->b_data);
> ext4_debug("mark inode bitmap %#04llx (+%llu)\n", input->inode_bitmap,
> input->inode_bitmap - start);
> - ext4_set_bit(input->inode_bitmap - start, bh->b_data);
> + ext4_test_and_set_bit(input->inode_bitmap - start, bh->b_data);
>
> /* Zero out all of the inode table blocks */
> block = input->inode_table;
> @@ -255,7 +255,7 @@ static int setup_new_group_blocks(struct super_block *sb,
> goto exit_bh;
> for (i = 0, bit = input->inode_table - start;
> i < sbi->s_itb_per_group; i++, bit++)
> - ext4_set_bit(bit, bh->b_data);
> + ext4_test_and_set_bit(bit, bh->b_data);
>
> if ((err = extend_or_restart_transaction(handle, 2, bh)))
> goto exit_bh;
> --
> 1.7.4.4
>
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