From cbae4d12eeee6b002a1252c4c45213651e8f4b55 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 12 Jan 2020 13:40:02 -0500 Subject: [PATCH] fold handle_mounts() into step_into() The following is true: * calls of handle_mounts() and step_into() are always paired in sequences like err = handle_mounts(nd, dentry, &path, &inode, &seq); if (unlikely(err < 0)) return err; err = step_into(nd, &path, flags, inode, seq); * in all such sequences path is uninitialized before and unused after this pair of calls * in all such sequences inode and seq are unused afterwards. So the call of handle_mounts() can be shifted inside step_into(), turning 'path' into a local variable in the combined function. Signed-off-by: Al Viro --- fs/namei.c | 41 +++++++++++++++-------------------------- 1 file changed, 15 insertions(+), 26 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 79f06be7f5d4..8a673f44ffc2 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1835,29 +1835,33 @@ enum {WALK_FOLLOW = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4}; * so we keep a cache of "no, this doesn't need follow_link" * for the common case. */ -static inline int step_into(struct nameidata *nd, struct path *path, - int flags, struct inode *inode, unsigned seq) +static int step_into(struct nameidata *nd, int flags, + struct dentry *dentry, struct inode *inode, unsigned seq) { - if (likely(!d_is_symlink(path->dentry)) || + struct path path; + int err = handle_mounts(nd, dentry, &path, &inode, &seq); + + if (err < 0) + return err; + if (likely(!d_is_symlink(path.dentry)) || !((flags & WALK_FOLLOW) || (nd->flags & LOOKUP_FOLLOW)) || (flags & WALK_NOFOLLOW)) { /* not a symlink or should not follow */ - path_to_nameidata(path, nd); + path_to_nameidata(&path, nd); nd->inode = inode; nd->seq = seq; return 0; } /* make sure that d_is_symlink above matches inode */ if (nd->flags & LOOKUP_RCU) { - if (read_seqcount_retry(&path->dentry->d_seq, seq)) + if (read_seqcount_retry(&path.dentry->d_seq, seq)) return -ECHILD; } - return pick_link(nd, path, inode, seq); + return pick_link(nd, &path, inode, seq); } static int walk_component(struct nameidata *nd, int flags) { - struct path path; struct dentry *dentry; struct inode *inode; unsigned seq; @@ -1883,11 +1887,7 @@ static int walk_component(struct nameidata *nd, int flags) } if (!(flags & WALK_MORE) && nd->depth) put_link(nd); - - err = handle_mounts(nd, dentry, &path, &inode, &seq); - if (unlikely(err < 0)) - return err; - return step_into(nd, &path, flags, inode, seq); + return step_into(nd, flags, dentry, inode, seq); } /* @@ -2354,17 +2354,10 @@ static inline int lookup_last(struct nameidata *nd) static int handle_lookup_down(struct nameidata *nd) { - struct path path; - struct inode *inode = nd->inode; - unsigned seq = nd->seq; - int err; - if (!(nd->flags & LOOKUP_RCU)) dget(nd->path.dentry); - err = handle_mounts(nd, nd->path.dentry, &path, &inode, &seq); - if (unlikely(err < 0)) - return err; - return step_into(nd, &path, WALK_NOFOLLOW, inode, seq); + return step_into(nd, WALK_NOFOLLOW, + nd->path.dentry, nd->inode, nd->seq); } /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ @@ -3281,7 +3274,6 @@ static int do_last(struct nameidata *nd, int acc_mode = op->acc_mode; unsigned seq; struct inode *inode; - struct path path; struct dentry *dentry; int error; @@ -3384,10 +3376,7 @@ static int do_last(struct nameidata *nd, finish_lookup: if (nd->depth) put_link(nd); - error = handle_mounts(nd, dentry, &path, &inode, &seq); - if (unlikely(error < 0)) - return error; - error = step_into(nd, &path, 0, inode, seq); + error = step_into(nd, 0, dentry, inode, seq); if (unlikely(error)) return error; -- 2.11.0