From c9f2dfb7b59e5a6db054f821a6e1a6db8fa57d64 Mon Sep 17 00:00:00 2001 From: Imran Khan Date: Thu, 9 Mar 2023 22:09:31 +1100 Subject: kernfs: Use a per-fs rwsem to protect per-fs list of kernfs_super_info. Right now per-fs kernfs_rwsem protects list of kernfs_super_info instances for a kernfs_root. Since kernfs_rwsem is used to synchronize several other operations across kernfs and since most of these operations don't impact kernfs_super_info, we can use a separate per-fs rwsem to synchronize access to list of kernfs_super_info. This helps in reducing contention around kernfs_rwsem and also allows operations that change/access list of kernfs_super_info to proceed without contending for kernfs_rwsem. Signed-off-by: Imran Khan Link: https://lore.kernel.org/r/20230309110932.2889010-3-imran.f.khan@oracle.com Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/kernfs/file.c') diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index e4a50e4ff0d2..40c4661f15b7 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -922,8 +922,8 @@ repeat: root = kernfs_root(kn); /* kick fsnotify */ - down_write(&root->kernfs_rwsem); + down_read(&root->kernfs_supers_rwsem); list_for_each_entry(info, &kernfs_root(kn)->supers, node) { struct kernfs_node *parent; struct inode *p_inode = NULL; @@ -960,7 +960,7 @@ repeat: iput(inode); } - up_write(&root->kernfs_rwsem); + up_read(&root->kernfs_supers_rwsem); kernfs_put(kn); goto repeat; } -- cgit