[PATCH] fix allocation done in get_free_all_memory_range()

[PATCH] fix allocation done in get_free_all_memory_range()

[Jan Beulich]

Even when get_max_mapped() returns a value beyond the DMA32 range,
this can't be taken to mean an alocation from that range will succeed.
Hence, the code should still fall back to an allocation starting at
the bottom of memory if the first one failed.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

---
 kernel/early_res.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- linux-2.6.34-rc2/kernel/early_res.c	2010-03-25 15:23:45.000000000 +0100
+++ 2.6.34-rc2-get_free_all_memory_range-retry-alloc/kernel/early_res.c	2010-03-26 14:49:41.000000000 +0100
@@ -387,9 +387,7 @@ static void __init subtract_early_res(st
 int __init get_free_all_memory_range(struct range **rangep, int nodeid)
 {
 	int i, count;
-	u64 start = 0, end;
-	u64 size;
-	u64 mem;
+	u64 end, size, mem = -1ULL;
 	struct range *range;
 	int nr_range;
 
@@ -403,9 +401,11 @@ int __init get_free_all_memory_range(str
 	end = get_max_mapped();
 #ifdef MAX_DMA32_PFN
 	if (end > (MAX_DMA32_PFN << PAGE_SHIFT))
-		start = MAX_DMA32_PFN << PAGE_SHIFT;
+		mem = find_fw_memmap_area(MAX_DMA32_PFN << PAGE_SHIFT, end,
+					  size, sizeof(struct range));
 #endif
-	mem = find_fw_memmap_area(start, end, size, sizeof(struct range));
+	if (mem == -1ULL)
+		mem = find_fw_memmap_area(0, end, size, sizeof(struct range));
 	if (mem == -1ULL)
 		panic("can not find more space for range free");
 

Re: [PATCH] fix allocation done in get_free_all_memory_range()

[Yinghai Lu]

On 03/26/2010 09:41 AM, Jan Beulich wrote:
> Even when get_max_mapped() returns a value beyond the DMA32 range,
> this can't be taken to mean an alocation from that range will succeed.
> Hence, the code should still fall back to an allocation starting at
> the bottom of memory if the first one failed.
> 
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
> 
> ---
>  kernel/early_res.c |   10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> --- linux-2.6.34-rc2/kernel/early_res.c	2010-03-25 15:23:45.000000000 +0100
> +++ 2.6.34-rc2-get_free_all_memory_range-retry-alloc/kernel/early_res.c	2010-03-26 14:49:41.000000000 +0100
> @@ -387,9 +387,7 @@ static void __init subtract_early_res(st
>  int __init get_free_all_memory_range(struct range **rangep, int nodeid)
>  {
>  	int i, count;
> -	u64 start = 0, end;
> -	u64 size;
> -	u64 mem;
> +	u64 end, size, mem = -1ULL;
>  	struct range *range;
>  	int nr_range;
>  
> @@ -403,9 +401,11 @@ int __init get_free_all_memory_range(str
>  	end = get_max_mapped();
>  #ifdef MAX_DMA32_PFN
>  	if (end > (MAX_DMA32_PFN << PAGE_SHIFT))
> -		start = MAX_DMA32_PFN << PAGE_SHIFT;
> +		mem = find_fw_memmap_area(MAX_DMA32_PFN << PAGE_SHIFT, end,
> +					  size, sizeof(struct range));
>  #endif
> -	mem = find_fw_memmap_area(start, end, size, sizeof(struct range));
> +	if (mem == -1ULL)
> +		mem = find_fw_memmap_area(0, end, size, sizeof(struct range));
>  	if (mem == -1ULL)
>  		panic("can not find more space for range free");

Acked-by: Yinghai Lu <yinghai@kernel.org>

Thanks for catching it.

Yinghai