Re: [PATCH v2] arch: s390: appldata: using strncpy() and strnlen() instead of sprintf()

[Chen Gang <gang.chen@asianux.com>]

On 05/29/2013 02:30 PM, Dan Carpenter wrote:
> On Wed, May 29, 2013 at 09:28:43AM +0800, Chen Gang wrote:
> 
>> > diff --git a/arch/s390/appldata/appldata_base.c b/arch/s390/appldata/appldata_base.c
>> > index bae0f40..27f200d 100644
>> > --- a/arch/s390/appldata/appldata_base.c
>> > +++ b/arch/s390/appldata/appldata_base.c
>> > @@ -212,10 +212,9 @@ appldata_timer_handler(ctl_table *ctl, int write,
>> >  		return 0;
>> >  	}
>> >  	if (!write) {
>> > -		len = sprintf(buf, appldata_timer_active ? "1\n" : "0\n");
>> > -		if (len > *lenp)
>> > -			len = *lenp;
>> > -		if (copy_to_user(buffer, buf, len))
>> > +		if (copy_to_user(buffer,
>> > +				 appldata_timer_active ? "1\n" : "0\n",
>> > +				 min(2, *lenp))
> I don't have a cross compiler set up, but this will generate a
> warning, I think.  min_t() is needed.

Yes, it even can not pass compiling: need additional ')' for 'if'.

The new fix is below, (for pass compiling, also need fix the incorrect
declaration, which I have already sent an individual patch for it).

-----------------------------diff v2 begin------------------------------

diff --git a/arch/s390/appldata/appldata_base.c
b/arch/s390/appldata/appldata_base.c
index bae0f40..b0915b4 100644
--- a/arch/s390/appldata/appldata_base.c
+++ b/arch/s390/appldata/appldata_base.c
@@ -212,10 +212,9 @@ appldata_timer_handler(ctl_table *ctl, int write,
 		return 0;
 	}
 	if (!write) {
-		len = sprintf(buf, appldata_timer_active ? "1\n" : "0\n");
-		if (len > *lenp)
-			len = *lenp;
-		if (copy_to_user(buffer, buf, len))
+		if (copy_to_user(buffer,
+				 appldata_timer_active ? "1\n" : "0\n",
+				 min_t(size_t, 2, *lenp)))
 			return -EFAULT;
 		goto out;
 	}
diff --git a/arch/s390/include/asm/pgtable.h
b/arch/s390/include/asm/pgtable.h
index 172209c..ed88890 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1348,7 +1348,7 @@ static inline pmd_t pmd_mkwrite(pmd_t pmd)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE

 #define __HAVE_ARCH_PGTABLE_DEPOSIT
-extern void pgtable_trans_huge_deposit(struct mm_struct *mm, , pmd_t *pmdp,
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 				       pgtable_t pgtable);

 #define __HAVE_ARCH_PGTABLE_WITHDRAW


-----------------------------diff v2 end--------------------------------


For cross compiler, I use fedora 16/17, can yum update binutils-*
to get many platform cross-compilers (s390, powerpc, arm, xtensa, ...).


Thanks.
-- 
Chen Gang

Asianux Corporation