* [PATCH] cpumask: fix double string traverse in cpumask_parse @ 2019-04-09 20:42 Yury Norov 2019-04-09 21:31 ` Rasmus Villemoes 2019-04-09 21:36 ` Andrew Morton 0 siblings, 2 replies; 4+ messages in thread From: Yury Norov @ 2019-04-09 20:42 UTC (permalink / raw) To: Andrew Morton, Andy Shevchenko, Rasmus Villemoes, Amritha Nambiar, David S. Miller, Tejun Heo, Willem de Bruijn Cc: Yury Norov, Yury Norov, linux-kernel From: Yury Norov <ynorov@marvell.com> cpumask_parse() finds first occurrence of either \n or \0 by calling strchr() and strlen(). We can do it better with a single call of strchrnul(). Signed-off-by: Yury Norov <ynorov@marvell.com> --- include/linux/cpumask.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 147bdec42215..2b87f35c586c 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -633,8 +633,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, */ static inline int cpumask_parse(const char *buf, struct cpumask *dstp) { - char *nl = strchr(buf, '\n'); - unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); + unsigned int len = (unsigned int)(strchrnul(buf, '\n') - buf); return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits); } -- 2.17.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cpumask: fix double string traverse in cpumask_parse 2019-04-09 20:42 [PATCH] cpumask: fix double string traverse in cpumask_parse Yury Norov @ 2019-04-09 21:31 ` Rasmus Villemoes 2019-04-09 21:39 ` Yury Norov 2019-04-09 21:36 ` Andrew Morton 1 sibling, 1 reply; 4+ messages in thread From: Rasmus Villemoes @ 2019-04-09 21:31 UTC (permalink / raw) To: Yury Norov, Andrew Morton, Andy Shevchenko, Amritha Nambiar, David S. Miller, Tejun Heo, Willem de Bruijn Cc: Yury Norov, linux-kernel On 09/04/2019 22.42, Yury Norov wrote: > From: Yury Norov <ynorov@marvell.com> > > cpumask_parse() finds first occurrence of either \n or \0 by calling > strchr() and strlen(). We can do it better with a single call of > strchrnul(). > > Signed-off-by: Yury Norov <ynorov@marvell.com> > --- > include/linux/cpumask.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > index 147bdec42215..2b87f35c586c 100644 > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -633,8 +633,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, > */ > static inline int cpumask_parse(const char *buf, struct cpumask *dstp) > { > - char *nl = strchr(buf, '\n'); > - unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); > + unsigned int len = (unsigned int)(strchrnul(buf, '\n') - buf); ack, but please drop the cast. "len = strchrnul(buf, '\n') - buf;" Rasmus ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cpumask: fix double string traverse in cpumask_parse 2019-04-09 21:31 ` Rasmus Villemoes @ 2019-04-09 21:39 ` Yury Norov 0 siblings, 0 replies; 4+ messages in thread From: Yury Norov @ 2019-04-09 21:39 UTC (permalink / raw) To: Rasmus Villemoes Cc: Andrew Morton, Andy Shevchenko, Amritha Nambiar, David S. Miller, Tejun Heo, Willem de Bruijn, Yury Norov, linux-kernel On Tue, Apr 09, 2019 at 11:31:50PM +0200, Rasmus Villemoes wrote: > On 09/04/2019 22.42, Yury Norov wrote: > > From: Yury Norov <ynorov@marvell.com> > > > > cpumask_parse() finds first occurrence of either \n or \0 by calling > > strchr() and strlen(). We can do it better with a single call of > > strchrnul(). > > > > Signed-off-by: Yury Norov <ynorov@marvell.com> > > --- > > include/linux/cpumask.h | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > > index 147bdec42215..2b87f35c586c 100644 > > --- a/include/linux/cpumask.h > > +++ b/include/linux/cpumask.h > > @@ -633,8 +633,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, > > */ > > static inline int cpumask_parse(const char *buf, struct cpumask *dstp) > > { > > - char *nl = strchr(buf, '\n'); > > - unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); > > + unsigned int len = (unsigned int)(strchrnul(buf, '\n') - buf); > > ack, but please drop the cast. "len = strchrnul(buf, '\n') - buf;" Indeed. See below. Thanks, Yury Subject: [PATCH] cpumask: fix double string traverse in cpumask_parse From: Yury Norov <ynorov@marvell.com> cpumask_parse() finds first occurrence of either \n or \0 by calling strchr() and strlen(). We can do it better with a single call of strchrnul(). Signed-off-by: Yury Norov <ynorov@marvell.com> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- include/linux/cpumask.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 147bdec42215..2b87f35c586c 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -633,8 +633,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, */ static inline int cpumask_parse(const char *buf, struct cpumask *dstp) { - char *nl = strchr(buf, '\n'); - unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); + unsigned int len = strchrnul(buf, '\n') - buf; return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits); } -- 2.17.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cpumask: fix double string traverse in cpumask_parse 2019-04-09 20:42 [PATCH] cpumask: fix double string traverse in cpumask_parse Yury Norov 2019-04-09 21:31 ` Rasmus Villemoes @ 2019-04-09 21:36 ` Andrew Morton 1 sibling, 0 replies; 4+ messages in thread From: Andrew Morton @ 2019-04-09 21:36 UTC (permalink / raw) To: Yury Norov Cc: Andy Shevchenko, Rasmus Villemoes, Amritha Nambiar, David S. Miller, Tejun Heo, Willem de Bruijn, Yury Norov, linux-kernel On Tue, 9 Apr 2019 13:42:08 -0700 Yury Norov <yury.norov@gmail.com> wrote: > From: Yury Norov <ynorov@marvell.com> > > cpumask_parse() finds first occurrence of either \n or \0 by calling > strchr() and strlen(). We can do it better with a single call of > strchrnul(). Fair enough. > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -633,8 +633,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, > */ > static inline int cpumask_parse(const char *buf, struct cpumask *dstp) > { > - char *nl = strchr(buf, '\n'); > - unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); > + unsigned int len = (unsigned int)(strchrnul(buf, '\n') - buf); Does the cast do anything useful? The compiler will convert a ptrdiff_t to uint without issues, I think? > return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits); > } ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-04-09 21:39 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-04-09 20:42 [PATCH] cpumask: fix double string traverse in cpumask_parse Yury Norov 2019-04-09 21:31 ` Rasmus Villemoes 2019-04-09 21:39 ` Yury Norov 2019-04-09 21:36 ` Andrew Morton
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