[PATCH 1/6] MIPS: irixelf: fix test unsigned var < 0

[PATCH 1/6] MIPS: irixelf: fix test unsigned var < 0

[Roel Kluin]

v is unsigned, cast to signed to evaluate the do_brk() return value,
    
Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/arch/mips/kernel/irixelf.c b/arch/mips/kernel/irixelf.c
index 290d8e3..fad2a2a 100644
--- a/arch/mips/kernel/irixelf.c
+++ b/arch/mips/kernel/irixelf.c
@@ -583,15 +583,15 @@ static void irix_map_prda_page(void)
 	unsigned long v;
 	struct prda *pp;
 
 	down_write(&current->mm->mmap_sem);
 	v =  do_brk(PRDA_ADDRESS, PAGE_SIZE);
 	up_write(&current->mm->mmap_sem);
 
-	if (v < 0)
+	if ((long) v < 0)
 		return;
 
 	pp = (struct prda *) v;
 	pp->prda_sys.t_pid  = task_pid_vnr(current);
 	pp->prda_sys.t_prid = read_c0_prid();
 	pp->prda_sys.t_rpid = task_pid_vnr(current);
 

Re: [PATCH 1/6] MIPS: irixelf: fix test unsigned var < 0

[Ralf Baechle]

On Wed, Apr 16, 2008 at 03:39:22AM +0200, Roel Kluin wrote:

> v is unsigned, cast to signed to evaluate the do_brk() return value,

do_brk() is expected to return its first argument as the result in case
of success.  An error also wasn't getting propagated so some further
fixes were needed for irix_map_prda_page and its caller.  So I'll apply
a different fix.

Thanks!

  Ralf

Re: [PATCH 1/6] MIPS: irixelf: fix test unsigned var < 0

[Marcin Slusarz]

On Wed, Apr 16, 2008 at 03:39:22AM +0200, Roel Kluin wrote:
> v is unsigned, cast to signed to evaluate the do_brk() return value,
>     
> Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
> ---
> diff --git a/arch/mips/kernel/irixelf.c b/arch/mips/kernel/irixelf.c
> index 290d8e3..fad2a2a 100644
> --- a/arch/mips/kernel/irixelf.c
> +++ b/arch/mips/kernel/irixelf.c
> @@ -583,15 +583,15 @@ static void irix_map_prda_page(void)
>  	unsigned long v;
>  	struct prda *pp;
>  
>  	down_write(&current->mm->mmap_sem);
>  	v =  do_brk(PRDA_ADDRESS, PAGE_SIZE);
>  	up_write(&current->mm->mmap_sem);
>  
> -	if (v < 0)
> +	if ((long) v < 0)
maybe cast it earlier (to struct prda *) and check error with IS_ERR?

>  		return;
>  
>  	pp = (struct prda *) v;
>  	pp->prda_sys.t_pid  = task_pid_vnr(current);
>  	pp->prda_sys.t_prid = read_c0_prid();
>  	pp->prda_sys.t_rpid = task_pid_vnr(current);
>  
> 
> --
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