On 11/6/2013 12:56 PM, Nitin Gupta wrote: > On Tue, Nov 5, 2013 at 5:17 PM, David Cohen > <david.a.cohen@xxxxxxxxxxxxxxx> wrote: >> 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. >> >> > > Using a hardcoded 1 looks fine in this case. But the patch description > should also be added as a comment for this function. Otherwise, the patch > looks good to me. > Sure, I can add a comment above obj_location_to_handle() and obj_handle_to_location(). Olav Haugan -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- 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
