Commit 4b68f6df authored by Harshad Shirwadkar's avatar Harshad Shirwadkar Committed by Theodore Ts'o
Browse files

ext4: add MB_NUM_ORDERS macro 



A few arrays in mballoc.c use the total number of valid orders as
their size. Currently, this value is set as "sb->s_blocksize_bits +
2". This makes code harder to read. So, instead add a new macro
MB_NUM_ORDERS(sb) to make the code more readable.

Signed-off-by: default avatarHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: default avatarAndreas Dilger <adilger@dilger.ca>
Reviewed-by: default avatarRitesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-5-harshadshirwadkar@gmail.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent a6c75eaf

fs/ext4/mballoc.c

+10 −9
Original line number Diff line number Diff line
@@ -756,7 +756,7 @@ mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp) 


	grp->bb_largest_free_order = -1; /* uninit */



	bits = sb->s_blocksize_bits + 1;

	bits = MB_NUM_ORDERS(sb) - 1;

	for (i = bits; i >= 0; i--) {

		if (grp->bb_counters[i] > 0) {

			grp->bb_largest_free_order = i;
@@ -957,7 +957,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp) 
			grinfo->bb_fragments = 0;

			memset(grinfo->bb_counters, 0,

			       sizeof(*grinfo->bb_counters) *

				(sb->s_blocksize_bits+2));

			       (MB_NUM_ORDERS(sb)));

			/*

			 * incore got set to the group block bitmap below

			 */
@@ -1928,7 +1928,7 @@ void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac, 
	int max;



	BUG_ON(ac->ac_2order <= 0);

	for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {

	for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) {

		if (grp->bb_counters[i] == 0)

			continue;
@@ -2107,7 +2107,7 @@ static bool ext4_mb_good_group(struct ext4_allocation_context *ac, 
		if (free < ac->ac_g_ex.fe_len)

			return false;



		if (ac->ac_2order > ac->ac_sb->s_blocksize_bits+1)

		if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb))

			return true;



		if (grp->bb_largest_free_order < ac->ac_2order)
@@ -2315,13 +2315,13 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) 
	 * We also support searching for power-of-two requests only for

	 * requests upto maximum buddy size we have constructed.

	 */

	if (i >= sbi->s_mb_order2_reqs && i <= sb->s_blocksize_bits + 2) {

	if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) {

		/*

		 * This should tell if fe_len is exactly power of 2

		 */

		if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)

			ac->ac_2order = array_index_nospec(i - 1,

							   sb->s_blocksize_bits + 2);

							   MB_NUM_ORDERS(sb));

	}



	/* if stream allocation is enabled, use global goal */
@@ -2880,7 +2880,7 @@ int ext4_mb_init(struct super_block *sb) 
	unsigned max;

	int ret;



	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);

	i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets);



	sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);

	if (sbi->s_mb_offsets == NULL) {
@@ -2888,7 +2888,7 @@ int ext4_mb_init(struct super_block *sb) 
		goto out;

	}



	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);

	i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs);

	sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);

	if (sbi->s_mb_maxs == NULL) {

		ret = -ENOMEM;
@@ -2914,7 +2914,8 @@ int ext4_mb_init(struct super_block *sb) 
		offset_incr = offset_incr >> 1;

		max = max >> 1;

		i++;

	} while (i <= sb->s_blocksize_bits + 1);

	} while (i < MB_NUM_ORDERS(sb));





	spin_lock_init(&sbi->s_md_lock);

	sbi->s_mb_free_pending = 0;

fs/ext4/mballoc.h

+5 −0
Original line number Diff line number Diff line
@@ -78,6 +78,11 @@ 
 */

#define MB_DEFAULT_MAX_INODE_PREALLOC	512



/*

 * Number of valid buddy orders

 */

#define MB_NUM_ORDERS(sb)		((sb)->s_blocksize_bits + 2)



struct ext4_free_data {

	/* this links the free block information from sb_info */

	struct list_head		efd_list;