pick_link(): take reserving space on stack into a new helper (49055906) · Commits · 戴 / test

fs/namei.c

+25 −21

Original line number	Diff line number	Diff line
		@@ -1580,22 +1580,15 @@ static inline int may_lookup(struct nameidata *nd)
		return inode_permission(nd->inode, MAY_EXEC);
		}

		enum {WALK_TRAILING = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};

		static const char pick_link(struct nameidata nd, struct path *link,
		struct inode *inode, unsigned seq, int flags)
		static int reserve_stack(struct nameidata nd, struct path link, unsigned seq)
		{
		struct saved *last;
		const char *res;
		int error;

		if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) {
		if (!(nd->flags & LOOKUP_RCU))
		path_put(link);
		return ERR_PTR(-ELOOP);
		}
		if (unlikely(nd->total_link_count++ >= MAXSYMLINKS))
		return -ELOOP;
		error = nd_alloc_stack(nd);
		if (unlikely(error)) {
		if (likely(!error))
		return 0;
		if (error == -ECHILD) {
		// we must grab link first
		bool grabbed_link = legitimize_path(nd, link, seq);
		@@ -1606,12 +1599,23 @@ static const char pick_link(struct nameidata nd, struct path *link,
		if (!error)
		error = nd_alloc_stack(nd);
		}
		if (error) {
		return error;
		}

		enum {WALK_TRAILING = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};

		static const char pick_link(struct nameidata nd, struct path *link,
		struct inode *inode, unsigned seq, int flags)
		{
		struct saved *last;
		const char *res;
		int error = reserve_stack(nd, link, seq);

		if (unlikely(error)) {
		if (!(nd->flags & LOOKUP_RCU))
		path_put(link);
		return ERR_PTR(error);
		}
		}

		last = nd->stack + nd->depth++;
		last->link = *link;
		clear_delayed_call(&last->done);