* [PATCH] kexec: use min_t/max_t to avoid 'if (foo == bar)' thing
@ 2013-02-24 4:03 Zhang Yanfei
2013-02-24 10:55 ` Simon Horman
0 siblings, 1 reply; 3+ messages in thread
From: Zhang Yanfei @ 2013-02-24 4:03 UTC (permalink / raw)
To: Eric W. Biederman, Andrew Morton
Cc: Simon Horman, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org
This is just a tweak: using min_t/max_t to avoid `if (foo = bar)' thing.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
kernel/kexec.c | 20 +++++---------------
1 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 2436ffc..065db87 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -822,13 +822,8 @@ static int kimage_load_normal_segment(struct kimage *image,
/* Start with a clear page */
clear_page(ptr);
ptr += maddr & ~PAGE_MASK;
- mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
- if (mchunk > mbytes)
- mchunk = mbytes;
-
- uchunk = mchunk;
- if (uchunk > ubytes)
- uchunk = ubytes;
+ mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK));
+ uchunk = min_t(size_t, ubytes, mchunk);
result = copy_from_user(ptr, buf, uchunk);
kunmap(page);
@@ -874,13 +869,9 @@ static int kimage_load_crash_segment(struct kimage *image,
}
ptr = kmap(page);
ptr += maddr & ~PAGE_MASK;
- mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
- if (mchunk > mbytes)
- mchunk = mbytes;
-
- uchunk = mchunk;
+ mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK));
+ uchunk = min_t(size_t, ubytes, mchunk);
if (uchunk > ubytes) {
- uchunk = ubytes;
/* Zero the trailing part of the page */
memset(ptr + uchunk, 0, mchunk - uchunk);
}
@@ -1461,8 +1452,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
r = vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
- if (r + vmcoreinfo_size > vmcoreinfo_max_size)
- r = vmcoreinfo_max_size - vmcoreinfo_size;
+ r = min_t(size_t, r, vmcoreinfo_max_size - vmcoreinfo_size);
memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
--
1.7.1
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] kexec: use min_t/max_t to avoid 'if (foo == bar)' thing
2013-02-24 4:03 [PATCH] kexec: use min_t/max_t to avoid 'if (foo == bar)' thing Zhang Yanfei
@ 2013-02-24 10:55 ` Simon Horman
2013-02-24 12:59 ` Zhang Yanfei
0 siblings, 1 reply; 3+ messages in thread
From: Simon Horman @ 2013-02-24 10:55 UTC (permalink / raw)
To: Zhang Yanfei
Cc: Andrew Morton, kexec@lists.infradead.org, Eric W. Biederman,
linux-kernel@vger.kernel.org
On Sun, Feb 24, 2013 at 12:03:00PM +0800, Zhang Yanfei wrote:
> This is just a tweak: using min_t/max_t to avoid `if (foo = bar)' thing.
- s/=/==/; s/[/]max_t//
But in any case the change is more than that.
I'd be happier with something like:
kexec: Use min_t to simplify logic
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Simon Horman <horms@verge.net.au>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
> kernel/kexec.c | 20 +++++---------------
> 1 files changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 2436ffc..065db87 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -822,13 +822,8 @@ static int kimage_load_normal_segment(struct kimage *image,
> /* Start with a clear page */
> clear_page(ptr);
> ptr += maddr & ~PAGE_MASK;
> - mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
> - if (mchunk > mbytes)
> - mchunk = mbytes;
> -
> - uchunk = mchunk;
> - if (uchunk > ubytes)
> - uchunk = ubytes;
> + mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK));
> + uchunk = min_t(size_t, ubytes, mchunk);
>
> result = copy_from_user(ptr, buf, uchunk);
> kunmap(page);
> @@ -874,13 +869,9 @@ static int kimage_load_crash_segment(struct kimage *image,
> }
> ptr = kmap(page);
> ptr += maddr & ~PAGE_MASK;
> - mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
> - if (mchunk > mbytes)
> - mchunk = mbytes;
> -
> - uchunk = mchunk;
> + mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK));
> + uchunk = min_t(size_t, ubytes, mchunk);
The line above means that uchunk can now never be greater than ubytes.
> if (uchunk > ubytes) {
So the following seems more appropriate to me:
if (mchunk > uchunk) {
> - uchunk = ubytes;
> /* Zero the trailing part of the page */
> memset(ptr + uchunk, 0, mchunk - uchunk);
> }
> @@ -1461,8 +1452,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
> r = vsnprintf(buf, sizeof(buf), fmt, args);
> va_end(args);
>
> - if (r + vmcoreinfo_size > vmcoreinfo_max_size)
> - r = vmcoreinfo_max_size - vmcoreinfo_size;
> + r = min_t(size_t, r, vmcoreinfo_max_size - vmcoreinfo_size);
>
> memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
>
> --
> 1.7.1
>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] kexec: use min_t/max_t to avoid 'if (foo == bar)' thing
2013-02-24 10:55 ` Simon Horman
@ 2013-02-24 12:59 ` Zhang Yanfei
0 siblings, 0 replies; 3+ messages in thread
From: Zhang Yanfei @ 2013-02-24 12:59 UTC (permalink / raw)
To: Simon Horman
Cc: kexec@lists.infradead.org, Andrew Morton, Zhang Yanfei,
Eric W. Biederman, linux-kernel@vger.kernel.org
于 2013年02月24日 18:55, Simon Horman 写道:
> On Sun, Feb 24, 2013 at 12:03:00PM +0800, Zhang Yanfei wrote:
>> This is just a tweak: using min_t/max_t to avoid `if (foo = bar)' thing.
>
> - s/=/==/; s/[/]max_t//
>
>
> But in any case the change is more than that.
> I'd be happier with something like:
>
> kexec: Use min_t to simplify logic
Hmm, agreed.
>
>> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Simon Horman <horms@verge.net.au>
>> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
>> ---
>> kernel/kexec.c | 20 +++++---------------
>> 1 files changed, 5 insertions(+), 15 deletions(-)
>>
>> diff --git a/kernel/kexec.c b/kernel/kexec.c
>> index 2436ffc..065db87 100644
>> --- a/kernel/kexec.c
>> +++ b/kernel/kexec.c
>> @@ -822,13 +822,8 @@ static int kimage_load_normal_segment(struct kimage *image,
>> /* Start with a clear page */
>> clear_page(ptr);
>> ptr += maddr & ~PAGE_MASK;
>> - mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
>> - if (mchunk > mbytes)
>> - mchunk = mbytes;
>> -
>> - uchunk = mchunk;
>> - if (uchunk > ubytes)
>> - uchunk = ubytes;
>> + mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK));
>> + uchunk = min_t(size_t, ubytes, mchunk);
>>
>> result = copy_from_user(ptr, buf, uchunk);
>> kunmap(page);
>> @@ -874,13 +869,9 @@ static int kimage_load_crash_segment(struct kimage *image,
>> }
>> ptr = kmap(page);
>> ptr += maddr & ~PAGE_MASK;
>> - mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
>> - if (mchunk > mbytes)
>> - mchunk = mbytes;
>> -
>> - uchunk = mchunk;
>> + mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK));
>> + uchunk = min_t(size_t, ubytes, mchunk);
>
> The line above means that uchunk can now never be greater than ubytes.
>
>> if (uchunk > ubytes) {
>
> So the following seems more appropriate to me:
>
> if (mchunk > uchunk) {
Oops, this is really a mistake. Thanks.
I will send the v2 patch.
>
>
>> - uchunk = ubytes;
>> /* Zero the trailing part of the page */
>> memset(ptr + uchunk, 0, mchunk - uchunk);
>> }
>> @@ -1461,8 +1452,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
>> r = vsnprintf(buf, sizeof(buf), fmt, args);
>> va_end(args);
>>
>> - if (r + vmcoreinfo_size > vmcoreinfo_max_size)
>> - r = vmcoreinfo_max_size - vmcoreinfo_size;
>> + r = min_t(size_t, r, vmcoreinfo_max_size - vmcoreinfo_size);
>>
>> memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
>>
>> --
>> 1.7.1
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-02-24 12:59 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-02-24 4:03 [PATCH] kexec: use min_t/max_t to avoid 'if (foo == bar)' thing Zhang Yanfei
2013-02-24 10:55 ` Simon Horman
2013-02-24 12:59 ` Zhang Yanfei
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox