Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 44183d42 authored by Amir Goldstein's avatar Amir Goldstein Committed by Theodore Ts'o
Browse files

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: default avatarAmir Goldstein <amir73il@users.sf.net>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 9b8b7d35

fs/ext4/mballoc.c

+1 −30
Original line number Original line Diff line number Diff line
@@ -1130,24 +1130,8 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, 
	e4b->bd_group = group;

	e4b->bd_group = group;

	e4b->bd_buddy_page = NULL;

	e4b->bd_buddy_page = NULL;

	e4b->bd_bitmap_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))) {

	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

		 * we need full data about the group

		 * to make a good selection

		 * 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);

		ret = ext4_mb_init_group(sb, group);

		if (ret)

		if (ret)

			return 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);

		page_cache_release(e4b->bd_buddy_page);

	e4b->bd_buddy = NULL;

	e4b->bd_buddy = NULL;

	e4b->bd_bitmap = NULL;

	e4b->bd_bitmap = NULL;



	/* Done with the buddy cache */

	up_read(e4b->alloc_semp);

	return ret;

	return ret;

}

}
@@ -1259,9 +1239,6 @@ static void ext4_mb_unload_buddy(struct ext4_buddy *e4b) 
		page_cache_release(e4b->bd_bitmap_page);

		page_cache_release(e4b->bd_bitmap_page);

	if (e4b->bd_buddy_page)

	if (e4b->bd_buddy_page)

		page_cache_release(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);

	get_page(ac->ac_bitmap_page);

	ac->ac_buddy_page = e4b->bd_buddy_page;

	ac->ac_buddy_page = e4b->bd_buddy_page;

	get_page(ac->ac_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 */

	/* store last allocated for subsequent stream allocation */

	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {

	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {

		spin_lock(&sbi->s_md_lock);

		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);

			spin_unlock(&pa->pa_lock);

		}

		}

	}

	}

	if (ac->alloc_semp)

		up_read(ac->alloc_semp);

	if (pa) {

	if (pa) {

		/*

		/*

		 * We want to add the pa to the right bucket.

		 * We want to add the pa to the right bucket.

		 * Remove it from the list and while adding

		 * Remove it from the list and while adding

		 * make sure the list to which we are adding

		 * make sure the list to which we are adding

		 * doesn't grow big.  We need to release

		 * doesn't grow big.

		 * alloc_semp before calling ext4_mb_add_n_trim()

		 */

		 */

		if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {

		if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {

			spin_lock(pa->pa_obj_lock);

			spin_lock(pa->pa_obj_lock);

fs/ext4/mballoc.h

+0 −6
Original line number Original line Diff line number Diff line
@@ -193,11 +193,6 @@ struct ext4_allocation_context { 
	__u8 ac_op;		/* operation, for history only */

	__u8 ac_op;		/* operation, for history only */

	struct page *ac_bitmap_page;

	struct page *ac_bitmap_page;

	struct page *ac_buddy_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_prealloc_space *ac_pa;

	struct ext4_locality_group *ac_lg;

	struct ext4_locality_group *ac_lg;

};

};
@@ -215,7 +210,6 @@ struct ext4_buddy { 
	struct super_block *bd_sb;

	struct super_block *bd_sb;

	__u16 bd_blkbits;

	__u16 bd_blkbits;

	ext4_group_t bd_group;

	ext4_group_t bd_group;

	struct rw_semaphore *alloc_semp;

};

};

#define EXT4_MB_BITMAP(e4b)	((e4b)->bd_bitmap)

#define EXT4_MB_BITMAP(e4b)	((e4b)->bd_bitmap)

#define EXT4_MB_BUDDY(e4b)	((e4b)->bd_buddy)

#define EXT4_MB_BUDDY(e4b)	((e4b)->bd_buddy)