diff options
| author | Nick Piggin <npiggin@kernel.dk> | 2011-01-14 02:36:43 +0000 |
|---|---|---|
| committer | Nick Piggin <npiggin@hera.kernel.org> | 2011-01-14 02:36:43 +0000 |
| commit | 2c6755988afc003a0332406a134fb6a1626f9b28 (patch) | |
| tree | 84eea829cab7b28585000f6fd7fe0dc176b746c5 /include/linux/list_bl.h | |
| parent | 90dbb77ba48dddb87445d238e84cd137cf97dd98 (diff) | |
| download | lwn-2c6755988afc003a0332406a134fb6a1626f9b28.tar.gz lwn-2c6755988afc003a0332406a134fb6a1626f9b28.zip | |
fs: hlist UP debug fixup
Po-Yu Chuang <ratbert.chuang@gmail.com> 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 <npiggin@kernel.dk>
Diffstat (limited to 'include/linux/list_bl.h')
| -rw-r--r-- | include/linux/list_bl.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 9ee97e7f2be4..b2adbb4b2f73 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); } |