2021-03-15 17:40:13

by harshad shirwadkar

[permalink] [raw]
Subject: [PATCH v4 4/6] 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: Harshad Shirwadkar <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
fs/ext4/mballoc.c | 19 ++++++++++---------
fs/ext4/mballoc.h | 5 +++++
2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a4b71c9c1e66..15127d815461 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -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 */
@@ -2873,7 +2873,7 @@ 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) {
@@ -2881,7 +2881,7 @@ 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;
@@ -2907,7 +2907,8 @@ 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;
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index e75b4749aa1c..68111a10cfee 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -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;
--
2.31.0.rc2.261.g7f71774620-goog