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>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 1816eaf..254f1f9 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1130,24 +1130,8 @@
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 @@
ret = ext4_mb_init_group(sb, group);
if (ret)
return ret;
- goto repeat_load_buddy;
}
/*
@@ -1247,9 +1230,6 @@
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 @@
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 @@
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 @@
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);