[PATCH] i386 zone_sizes_init() fix

[PATCH] i386 zone_sizes_init() fix

[Wu Fengguang]

Now that with MAX_NR_ZONES=4, the last element of zones_size[] is
left uninitialized in zone_sizes_init() on i386.

Fix this by using gcc's range initializer to protect from future changes.

Signed-off-by: Wu Fengguang <wfg@mail.ustc.edu.cn>
---

--- linux-2.6.16-mm2.orig/arch/i386/mm/discontig.c
+++ linux-2.6.16-mm2/arch/i386/mm/discontig.c
@@ -355,7 +355,7 @@ void __init zone_sizes_init(void)
 
 
 	for_each_online_node(nid) {
-		unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
+		unsigned long zones_size[] = { [0 ... MAX_NR_ZONES-1] = 0 };
 		unsigned long *zholes_size;
 		unsigned int max_dma;
 
--- linux-2.6.16-mm2.orig/arch/i386/kernel/setup.c
+++ linux-2.6.16-mm2/arch/i386/kernel/setup.c
@@ -1203,7 +1203,7 @@ static unsigned long __init setup_memory
 
 void __init zone_sizes_init(void)
 {
-	unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
+	unsigned long zones_size[] = { [0 ... MAX_NR_ZONES-1] = 0 };
 	unsigned int max_dma, low;
 
 	max_dma = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;

Re: [PATCH] i386 zone_sizes_init() fix

[Andreas Schwab]

Wu Fengguang <wfg@mail.ustc.edu.cn> writes:

> Now that with MAX_NR_ZONES=4, the last element of zones_size[] is
> left uninitialized in zone_sizes_init() on i386.

No, it isn't.  In the presence of an initializer any element not
explicitly initialized will be set to 0 of the appropriate type.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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"And now for something completely different."

Re: [PATCH] i386 zone_sizes_init() fix

[Wu Fengguang]

On Sat, Apr 01, 2006 at 05:04:47PM +0200, Andreas Schwab wrote:
> Wu Fengguang <wfg@mail.ustc.edu.cn> writes:
> 
> > Now that with MAX_NR_ZONES=4, the last element of zones_size[] is
> > left uninitialized in zone_sizes_init() on i386.
> 
> No, it isn't.  In the presence of an initializer any element not
> explicitly initialized will be set to 0 of the appropriate type.

Got it, thanks for the tip.

Wu