From c8c06efa8b552608493b7066c234cfa82c47fcea Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 12 Dec 2014 16:54:24 -0800 Subject: mm: convert i_mmap_mutex to rwsem The i_mmap_mutex is a close cousin of the anon vma lock, both protecting similar data, one for file backed pages and the other for anon memory. To this end, this lock can also be a rwsem. In addition, there are some important opportunities to share the lock when there are no tree modifications. This conversion is straightforward. For now, all users take the write lock. [sfr@canb.auug.org.au: update fremap.c] Signed-off-by: Davidlohr Bueso Reviewed-by: Rik van Riel Acked-by: "Kirill A. Shutemov" Acked-by: Hugh Dickins Cc: Oleg Nesterov Acked-by: Peter Zijlstra (Intel) Cc: Srikar Dronamraju Acked-by: Mel Gorman Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hugetlbfs/inode.c | 10 +++++----- fs/inode.c | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'fs') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index a082709aa427..5eba47f593f8 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -472,12 +472,12 @@ static struct inode *hugetlbfs_get_root(struct super_block *sb, } /* - * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never + * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never * be taken from reclaim -- unlike regular filesystems. This needs an * annotation because huge_pmd_share() does an allocation under - * i_mmap_mutex. + * i_mmap_rwsem. */ -static struct lock_class_key hugetlbfs_i_mmap_mutex_key; +static struct lock_class_key hugetlbfs_i_mmap_rwsem_key; static struct inode *hugetlbfs_get_inode(struct super_block *sb, struct inode *dir, @@ -495,8 +495,8 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb, struct hugetlbfs_inode_info *info; inode->i_ino = get_next_ino(); inode_init_owner(inode, dir, mode); - lockdep_set_class(&inode->i_mapping->i_mmap_mutex, - &hugetlbfs_i_mmap_mutex_key); + lockdep_set_class(&inode->i_mapping->i_mmap_rwsem, + &hugetlbfs_i_mmap_rwsem_key); inode->i_mapping->a_ops = &hugetlbfs_aops; inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; diff --git a/fs/inode.c b/fs/inode.c index 2ed95f7caa4f..ad60555b4768 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -346,7 +346,7 @@ void address_space_init_once(struct address_space *mapping) memset(mapping, 0, sizeof(*mapping)); INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); spin_lock_init(&mapping->tree_lock); - mutex_init(&mapping->i_mmap_mutex); + init_rwsem(&mapping->i_mmap_rwsem); INIT_LIST_HEAD(&mapping->private_list); spin_lock_init(&mapping->private_lock); mapping->i_mmap = RB_ROOT; -- cgit v1.2.2