From: sudeep.holla@arm•com (Sudeep Holla)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 9/9] ARM: kernel: add outer cache support for cacheinfo implementation
Date: Thu, 26 Jun 2014 14:02:58 +0100 [thread overview]
Message-ID: <53AC1A02.2040704@arm.com> (raw)
In-Reply-To: <20140625223748.GM32514@n2100.arm.linux.org.uk>
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
next prev parent reply other threads:[~2014-06-26 13:02 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-25 17:30 [PATCH 0/9] drivers: cacheinfo support Sudeep Holla
2014-06-25 17:30 ` [PATCH 2/9] drivers: base: support cpu cache information interface to userspace via sysfs Sudeep Holla
2014-06-25 22:23 ` Russell King - ARM Linux
2014-06-26 18:41 ` Sudeep Holla
2014-06-26 18:50 ` Russell King - ARM Linux
2014-06-26 19:03 ` Sudeep Holla
2014-07-10 0:09 ` Greg Kroah-Hartman
2014-07-10 13:37 ` Sudeep Holla
2014-06-25 17:30 ` [PATCH 7/9] ARM64: kernel: add support for cpu cache information Sudeep Holla
2014-06-27 10:36 ` Mark Rutland
2014-06-27 11:22 ` Sudeep Holla
2014-06-27 11:34 ` Mark Rutland
2014-06-25 17:30 ` [PATCH 8/9] ARM: " Sudeep Holla
2014-06-25 22:33 ` Russell King - ARM Linux
2014-06-26 11:33 ` Sudeep Holla
2014-06-26 0:19 ` Stephen Boyd
2014-06-26 11:36 ` Sudeep Holla
2014-06-26 18:45 ` Stephen Boyd
2014-06-27 9:38 ` Sudeep Holla
2014-06-25 17:30 ` [PATCH 9/9] ARM: kernel: add outer cache support for cacheinfo implementation Sudeep Holla
2014-06-25 22:37 ` Russell King - ARM Linux
2014-06-26 13:02 ` Sudeep Holla [this message]
[not found] ` <1406306692-7135-1-git-send-email-sudeep.holla@arm.com>
2014-07-25 16:44 ` [PATCH v2 7/9] ARM64: kernel: add support for cpu cache information Sudeep Holla
2014-07-25 16:44 ` [PATCH v2 8/9] ARM: " Sudeep Holla
2014-07-25 16:44 ` [PATCH v2 9/9] ARM: kernel: add outer cache support for cacheinfo implementation Sudeep Holla
2014-08-21 10:59 ` [PATCH v3 00/11] drivers: cacheinfo support Sudeep Holla
2014-08-21 10:59 ` [PATCH v3 09/11] ARM64: kernel: add support for cpu cache information Sudeep Holla
2014-08-21 10:59 ` [PATCH v3 10/11] ARM: " Sudeep Holla
2014-08-21 10:59 ` [PATCH v3 11/11] ARM: kernel: add outer cache support for cacheinfo implementation Sudeep Holla
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