Re: [PATCH 2/3] mm/vmalloc: don't warning vmalloc allocationfailure twice

[Andrew Morton]

On Mon,  2 Sep 2013 20:35:44 +0800 Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> wrote:

> Don't warning twice in __vmalloc_area_node and __vmalloc_node_range if 
> __vmalloc_area_node allocation failure.
> 
> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
> ---
>  mm/vmalloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index ee41cc6..e324d38 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1635,7 +1635,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
>  
>  	addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
>  	if (!addr)
> -		goto fail;
> +		return NULL;
>  
>  	/*
>  	 * In this function, newly allocated vm_struct has VM_UNINITIALIZED

Putting a `return' in the middle of a function is often a bad thing -
functions which have multiple return points often lead to resource and
locking leaks.

It's particularly bad to have that return *after* a bunch of "goto
fail" statements - the result is utter spaghetti.

Fix:

--- a/mm/vmalloc.c~mm-vmalloc-dont-warn-about-vmalloc-allocation-failure-twice-fix
+++ a/mm/vmalloc.c
@@ -1626,16 +1626,16 @@ void *__vmalloc_node_range(unsigned long
 
 	size = PAGE_ALIGN(size);
 	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
-		goto fail;
+		goto warn;
 
 	area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED,
 				  start, end, node, gfp_mask, caller);
 	if (!area)
-		goto fail;
+		goto warn;
 
 	addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
 	if (!addr)
-		return NULL;
+		goto fail;
 
 	/*
 	 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
@@ -1653,10 +1653,11 @@ void *__vmalloc_node_range(unsigned long
 
 	return addr;
 
-fail:
+warn:
 	warn_alloc_failed(gfp_mask, 0,
 			  "vmalloc: allocation failure: %lu bytes\n",
 			  real_size);
+fail:
 	return NULL;
 }
 
_

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