Re: [PATCH] memory: fix alignment in eal_get_virtual_area()

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 13-Jun-18 8:08 PM, Dariusz Stojaczyk wrote:
> Although the alignment mechanism works as intended, the
> `no_align` bool flag was set incorrectly. We were aligning
> buffers that didn't need extra alignment, and weren't
> aligning ones that really needed it.
> 
> Fixes: b7cc54187ea4 ("mem: move virtual area function in common directory")
> Cc: anatoly.burakov@intel.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
> ---
>   lib/librte_eal/common/eal_common_memory.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
> index 4f0688f..a7c89f0 100644
> --- a/lib/librte_eal/common/eal_common_memory.c
> +++ b/lib/librte_eal/common/eal_common_memory.c
> @@ -70,7 +70,7 @@ eal_get_virtual_area(void *requested_addr, size_t *size,
>   	 * system page size is the same as requested page size.
>   	 */
>   	no_align = (requested_addr != NULL &&
> -		((uintptr_t)requested_addr & (page_sz - 1)) == 0) ||
> +		((uintptr_t)requested_addr & (page_sz - 1))) ||
>   		page_sz == system_page_sz;
>   
>   	do {
> 

This patch is wrong - no alignment should be performed if address is 
already alighed, e.g. if requested_addr & (page_sz - 1) == 0. The 
original code was correct.

Thomas, could you please revert this patch?

-- 
Thanks,
Anatoly