Hi Olav, On 11/05/2013 04:54 PM, Olav Haugan wrote:
zsmalloc encodes a handle using the page pfn and an object index. On some hardware platforms the pfn could be 0 and this causes the encoded handle to be 0 which is interpreted as an allocation failure. To prevent this false error we ensure that the encoded handle will not be 0 when allocation succeeds. Change-Id: Ifff930dcf254915b497aec5cb36f152a5e5365d6 Signed-off-by: Olav Haugan <ohaugan@xxxxxxxxxxxxxx> --- drivers/staging/zsmalloc/zsmalloc-main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c index 523b937..0e32c0f 100644 --- a/drivers/staging/zsmalloc/zsmalloc-main.c +++ b/drivers/staging/zsmalloc/zsmalloc-main.c @@ -441,7 +441,7 @@ static void *obj_location_to_handle(struct page *page, unsigned long obj_idx) } handle = page_to_pfn(page) << OBJ_INDEX_BITS; - handle |= (obj_idx & OBJ_INDEX_MASK); + handle |= ((obj_idx + 1) & OBJ_INDEX_MASK);
As suggestion you could use a macro instead of hardcoded 1. I am not familiar with this code, but if it's a valid test to verify if the resulting address is page aligned, you might want to set this offset macro to a page aligned value as well.
return (void *)handle; } @@ -451,7 +451,7 @@ static void obj_handle_to_location(unsigned long handle, struct page **page, unsigned long *obj_idx) { *page = pfn_to_page(handle >> OBJ_INDEX_BITS); - *obj_idx = handle & OBJ_INDEX_MASK; + *obj_idx = (handle & OBJ_INDEX_MASK) - 1;
Ditto. Br, David Cohen -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html