From: Nick Piggin Date: Fri, 14 Jan 2011 02:36:43 +0000 (+0000) Subject: fs: hlist UP debug fixup X-Git-Tag: v2.6.38-rc1~60^2~5 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2c6755988afc003a0332406a134fb6a1626f9b28;p=platform%2Fkernel%2Flinux-3.10.git fs: hlist UP debug fixup Po-Yu Chuang noticed that hlist_bl_set_first could crash on a UP system when LIST_BL_LOCKMASK is 0, because LIST_BL_BUG_ON(!((unsigned long)h->first & LIST_BL_LOCKMASK)); always evaulates to true. Fix the expression, and also avoid a dependency between bit spinlock implementation and list bl code (list code shouldn't know anything except that bit 0 is set when adding and removing elements). Eventually if a good use case comes up, we might use this list to store 1 or more arbitrary bits of data, so it really shouldn't be tied to locking either, but for now they are helpful for debugging. Signed-off-by: Nick Piggin --- diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 9ee97e7..b2adbb4 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -16,7 +16,7 @@ * some fast and compact auxiliary data. */ -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) +#if defined(CONFIG_SMP) #define LIST_BL_LOCKMASK 1UL #else #define LIST_BL_LOCKMASK 0UL @@ -62,7 +62,8 @@ static inline void hlist_bl_set_first(struct hlist_bl_head *h, struct hlist_bl_node *n) { LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK); - LIST_BL_BUG_ON(!((unsigned long)h->first & LIST_BL_LOCKMASK)); + LIST_BL_BUG_ON(((unsigned long)h->first & LIST_BL_LOCKMASK) != + LIST_BL_LOCKMASK); h->first = (struct hlist_bl_node *)((unsigned long)n | LIST_BL_LOCKMASK); } diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h index b872b49..cf1244f 100644 --- a/include/linux/rculist_bl.h +++ b/include/linux/rculist_bl.h @@ -11,7 +11,8 @@ static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h, struct hlist_bl_node *n) { LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK); - LIST_BL_BUG_ON(!((unsigned long)h->first & LIST_BL_LOCKMASK)); + LIST_BL_BUG_ON(((unsigned long)h->first & LIST_BL_LOCKMASK) != + LIST_BL_LOCKMASK); rcu_assign_pointer(h->first, (struct hlist_bl_node *)((unsigned long)n | LIST_BL_LOCKMASK)); }