Hi Russell, On 25/06/14 23:37, Russell King - ARM Linux wrote:
On Wed, Jun 25, 2014 at 06:30:44PM +0100, Sudeep Holla wrote:diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c index efc5cab..30ca151 100644 --- a/arch/arm/mm/cache-l2x0.c +++ b/arch/arm/mm/cache-l2x0.c @@ -105,6 +105,15 @@ static inline void l2c_unlock(void __iomem *base, unsigned num) } }+static void l2x0_getinfo(struct outer_cache_info *info) +{ + if (!info) + return;Pointless NULL test. If someone passes NULL to this function (which you never do in this file) then we want to know about it because _that_ is a kernel bug - it is invalid to pass NULL. Hence the kernel should oops. Please, don't go around adding stupid NULL tests for conditions which should _never_ happen, instead, rely on the kernel to oops if these invalid conditions occur. That's why we produce a backtrace from such events, to allow invalid conditions to be debugged and fixed. Having stuff silently ignore in this way does not detect these bugs so they go by unnoticed. Take a moment to read some of the fs/ or kernel/ code, and you'll find a lack of NULL checks in there. That's what gives that code performance, because it's not spending its time doing loads of useless NULL checks.
Understood, will get rid of it.
@@ -894,6 +903,7 @@ static void __init __l2c_init(const struct l2c_init_data *data, data->enable(l2x0_base, aux, data->num_lock); outer_cache = fns; + outer_cache.get_info = l2x0_getinfo;NAK. Think about it.
Ah, will specify in l2c_init_data for individual implementations so that fixups is possible if needed for get_info. Sorry for missing this. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
