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ext4: remove alloc_semp 

After taking care of all group init races, all that remains is to
remove alloc_semp from ext4_allocation_context and ext4_buddy structs.

Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Amir Goldstein 2011-05-09 21:52:36 -04:00 committed by Theodore Ts'o
parent 9b8b7d353f
commit 44183d4231
2 changed files with 1 additions and 36 deletions
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31
fs/ext4/mballoc.c
View File

@ -1130,24 +1130,8 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
e4b->bd_group = group;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
e4b->alloc_semp = &grp->alloc_sem;
/* Take the read lock on the group alloc
* sem. This would make sure a parallel
* ext4_mb_init_group happening on other
* groups mapped by the page is blocked
* till we are done with allocation
*/
repeat_load_buddy:
down_read(e4b->alloc_semp);
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
/* we need to check for group need init flag
* with alloc_semp held so that we can be sure
* that new blocks didn't get added to the group
* when we are loading the buddy cache
*/
up_read(e4b->alloc_semp);
/*
* we need full data about the group
* to make a good selection
@ -1155,7 +1139,6 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
ret = ext4_mb_init_group(sb, group);
if (ret)
return ret;
goto repeat_load_buddy;
}
/*
@ -1247,9 +1230,6 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
page_cache_release(e4b->bd_buddy_page);
e4b->bd_buddy = NULL;
e4b->bd_bitmap = NULL;
/* Done with the buddy cache */
up_read(e4b->alloc_semp);
return ret;
}
@ -1259,9 +1239,6 @@ static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
page_cache_release(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
page_cache_release(e4b->bd_buddy_page);
/* Done with the buddy cache */
if (e4b->alloc_semp)
up_read(e4b->alloc_semp);
}
@ -1574,9 +1551,6 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
get_page(ac->ac_bitmap_page);
ac->ac_buddy_page = e4b->bd_buddy_page;
get_page(ac->ac_buddy_page);
/* on allocation we use ac to track the held semaphore */
ac->alloc_semp = e4b->alloc_semp;
e4b->alloc_semp = NULL;
/* store last allocated for subsequent stream allocation */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
spin_lock(&sbi->s_md_lock);
@ -4188,15 +4162,12 @@ static int ext4_mb_release_context(struct ext4_allocation_context *ac)
spin_unlock(&pa->pa_lock);
}
}
if (ac->alloc_semp)
up_read(ac->alloc_semp);
if (pa) {
/*
* We want to add the pa to the right bucket.
* Remove it from the list and while adding
* make sure the list to which we are adding
* doesn't grow big. We need to release
* alloc_semp before calling ext4_mb_add_n_trim()
* doesn't grow big.
*/
if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
spin_lock(pa->pa_obj_lock);

6
fs/ext4/mballoc.h
View File

@ -193,11 +193,6 @@ struct ext4_allocation_context {
__u8 ac_op; /* operation, for history only */
struct page *ac_bitmap_page;
struct page *ac_buddy_page;
/*
* pointer to the held semaphore upon successful
* block allocation
*/
struct rw_semaphore *alloc_semp;
struct ext4_prealloc_space *ac_pa;
struct ext4_locality_group *ac_lg;
};
@ -215,7 +210,6 @@ struct ext4_buddy {
struct super_block *bd_sb;
__u16 bd_blkbits;
ext4_group_t bd_group;
struct rw_semaphore *alloc_semp;
};
#define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
#define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)