From 3427ce7155412341aeb635c22c3ca2c2c9d1a978 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 30 Oct 2017 21:14:56 +0100 Subject: fsnotify: clean up fsnotify() Use helpers to get first and next marks from connector. Also get rid of inode_node/vfsmount_node local variables, which just refers to the same objects as iter_info. There was an srcu_dereference() for foo_node, but that's completely superfluous since we've already done it when obtaining foo_node. Also get rid of inode_group/vfsmount_group local variables; checking against non-NULL for these is the same as checking against non-NULL inode_mark/vfsmount_mark. Reviewed-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Jan Kara --- fs/notify/fsnotify.c | 105 ++++++++++++++++++++++----------------------------- 1 file changed, 45 insertions(+), 60 deletions(-) diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 074716293829..81d8959b6aef 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -243,6 +243,29 @@ static int send_to_group(struct inode *to_tell, file_name, cookie, iter_info); } +static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp) +{ + struct fsnotify_mark_connector *conn; + struct hlist_node *node = NULL; + + conn = srcu_dereference(*connp, &fsnotify_mark_srcu); + if (conn) + node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu); + + return hlist_entry_safe(node, struct fsnotify_mark, obj_list); +} + +static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark) +{ + struct hlist_node *node = NULL; + + if (mark) + node = srcu_dereference(mark->obj_list.next, + &fsnotify_mark_srcu); + + return hlist_entry_safe(node, struct fsnotify_mark, obj_list); +} + /* * This is the main call to fsnotify. The VFS calls into hook specific functions * in linux/fsnotify.h. Those functions then in turn call here. Here will call @@ -252,11 +275,7 @@ static int send_to_group(struct inode *to_tell, int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, const unsigned char *file_name, u32 cookie) { - struct hlist_node *inode_node = NULL, *vfsmount_node = NULL; - struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL; - struct fsnotify_group *inode_group, *vfsmount_group; - struct fsnotify_mark_connector *inode_conn, *vfsmount_conn; - struct fsnotify_iter_info iter_info; + struct fsnotify_iter_info iter_info = {}; struct mount *mnt; int ret = 0; /* global tests shouldn't care about events on child only the specific event */ @@ -291,26 +310,16 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, if ((mask & FS_MODIFY) || (test_mask & to_tell->i_fsnotify_mask)) { - inode_conn = srcu_dereference(to_tell->i_fsnotify_marks, - &fsnotify_mark_srcu); - if (inode_conn) - inode_node = srcu_dereference(inode_conn->list.first, - &fsnotify_mark_srcu); + iter_info.inode_mark = + fsnotify_first_mark(&to_tell->i_fsnotify_marks); } if (mnt && ((mask & FS_MODIFY) || (test_mask & mnt->mnt_fsnotify_mask))) { - inode_conn = srcu_dereference(to_tell->i_fsnotify_marks, - &fsnotify_mark_srcu); - if (inode_conn) - inode_node = srcu_dereference(inode_conn->list.first, - &fsnotify_mark_srcu); - vfsmount_conn = srcu_dereference(mnt->mnt_fsnotify_marks, - &fsnotify_mark_srcu); - if (vfsmount_conn) - vfsmount_node = srcu_dereference( - vfsmount_conn->list.first, - &fsnotify_mark_srcu); + iter_info.inode_mark = + fsnotify_first_mark(&to_tell->i_fsnotify_marks); + iter_info.vfsmount_mark = + fsnotify_first_mark(&mnt->mnt_fsnotify_marks); } /* @@ -318,41 +327,17 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, * ignore masks are properly reflected for mount mark notifications. * That's why this traversal is so complicated... */ - while (inode_node || vfsmount_node) { - inode_group = NULL; - inode_mark = NULL; - vfsmount_group = NULL; - vfsmount_mark = NULL; - - if (inode_node) { - inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu), - struct fsnotify_mark, obj_list); - inode_group = inode_mark->group; - } - - if (vfsmount_node) { - vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu), - struct fsnotify_mark, obj_list); - vfsmount_group = vfsmount_mark->group; - } - /* - * Need to protect both marks against freeing so that we can - * continue iteration from this place, regardless of which mark - * we actually happen to send an event for. - */ - iter_info.inode_mark = inode_mark; - iter_info.vfsmount_mark = vfsmount_mark; - - if (inode_group && vfsmount_group) { - int cmp = fsnotify_compare_groups(inode_group, - vfsmount_group); - if (cmp > 0) { - inode_group = NULL; + while (iter_info.inode_mark || iter_info.vfsmount_mark) { + struct fsnotify_mark *inode_mark = iter_info.inode_mark; + struct fsnotify_mark *vfsmount_mark = iter_info.vfsmount_mark; + + if (inode_mark && vfsmount_mark) { + int cmp = fsnotify_compare_groups(inode_mark->group, + vfsmount_mark->group); + if (cmp > 0) inode_mark = NULL; - } else if (cmp < 0) { - vfsmount_group = NULL; + else if (cmp < 0) vfsmount_mark = NULL; - } } ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask, @@ -362,12 +347,12 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) goto out; - if (inode_group) - inode_node = srcu_dereference(inode_node->next, - &fsnotify_mark_srcu); - if (vfsmount_group) - vfsmount_node = srcu_dereference(vfsmount_node->next, - &fsnotify_mark_srcu); + if (inode_mark) + iter_info.inode_mark = + fsnotify_next_mark(iter_info.inode_mark); + if (vfsmount_mark) + iter_info.vfsmount_mark = + fsnotify_next_mark(iter_info.vfsmount_mark); } ret = 0; out: -- cgit