Re: mm/slab.c: linux 2.6.1 fix 2 unguarded kmalloc and a PAGE_SHIFT

Re: mm/slab.c: linux 2.6.1 fix 2 unguarded kmalloc and a PAGE_SHIFT

[Manfred Spraul]

Hi Walter,

>this fixes catches 2 unguarded kmallocs() and changes a statement so that PAGE_SHIFT \
>>20 causes a warning.  At least sparc64 is prepared for a  PAGE_SHIFT >20.
>  
>
Why should a page shift above 20 generate a warning?

The two unguarded kmallocs are obivously wrong, but I'd prefer to guard 
them with __GFP_NOFAIL.

--
    Manfred

mm/slab.c: linux 2.6.1 fix 2 unguarded kmalloc and a PAGE_SHIFT

[Walter Harms]

Hi list,
this fixes catches 2 unguarded kmallocs() and changes a statement so that PAGE_SHIFT >20 causes a warning. 
At least sparc64 is prepared for a  PAGE_SHIFT >20.

hope that helps,
walter


--- mm/slab.c.org       2004-01-25 08:18:25.243165360 +0100
+++ mm/slab.c   2004-01-25 08:33:05.135401408 +0100
@@ -666,7 +666,7 @@
         * Fragmentation resistance on low memory - only use bigger
         * page orders on machines with more than 32MB of memory.
         */
-       if (num_physpages > (32 << 20) >> PAGE_SHIFT)
+       if (num_physpages > (32 << (20-PAGE_SHIFT) )
                slab_break_gfp_order = BREAK_GFP_ORDER_HI;
 
 
@@ -737,6 +737,10 @@
                void * ptr;
 
                ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
+
+               if (!ptr)
+                 BUG();
+
                local_irq_disable();
                BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache);
                memcpy(ptr, ac_data(&cache_cache), sizeof(struct arraycache_init
));
@@ -744,6 +748,10 @@
                local_irq_enable();
 
                ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
+
+               if (!ptr)
+                 BUG();
+
                local_irq_disable();
                BUG_ON(ac_data(malloc_sizes[0].cs_cachep) != &initarray_generic.
cache);
                memcpy(ptr, ac_data(malloc_sizes[0].cs_cachep),

Re: mm/slab.c: linux 2.6.1 fix 2 unguarded kmalloc and a PAGE_SHIFT

[Brian Gerst]

  (Walter Harms) wrote:
> Hi list,
> this fixes catches 2 unguarded kmallocs() and changes a statement so that PAGE_SHIFT >20 causes a warning. 
> At least sparc64 is prepared for a  PAGE_SHIFT >20.
> 
> hope that helps,
> walter
> 
> 
> --- mm/slab.c.org       2004-01-25 08:18:25.243165360 +0100
> +++ mm/slab.c   2004-01-25 08:33:05.135401408 +0100
> @@ -666,7 +666,7 @@
>          * Fragmentation resistance on low memory - only use bigger
>          * page orders on machines with more than 32MB of memory.
>          */
> -       if (num_physpages > (32 << 20) >> PAGE_SHIFT)
> +       if (num_physpages > (32 << (20-PAGE_SHIFT) )
>                 slab_break_gfp_order = BREAK_GFP_ORDER_HI;
>  
>  
> @@ -737,6 +737,10 @@
>                 void * ptr;
>  
>                 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
> +
> +               if (!ptr)
> +                 BUG();
> +
>                 local_irq_disable();
>                 BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache);
>                 memcpy(ptr, ac_data(&cache_cache), sizeof(struct arraycache_init
> ));
> @@ -744,6 +748,10 @@
>                 local_irq_enable();
>  
>                 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
> +
> +               if (!ptr)
> +                 BUG();
> +
>                 local_irq_disable();
>                 BUG_ON(ac_data(malloc_sizes[0].cs_cachep) != &initarray_generic.
> cache);
>                 memcpy(ptr, ac_data(malloc_sizes[0].cs_cachep),
> 
> -
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BUG_ON(!ptr) would be better.

--
				Brian Gerst