Re: [PATCH RESEND 1/8] s390: Start fallback of top-down mmap at mm->mmap_base

[Alex Ghiti]

Really sorry about that, my connection is weird this morning, I'll retry 
tomorrow.

Sorry again,

Alex

On 6/19/19 1:42 AM, Alexandre Ghiti wrote:
> In case of mmap failure in top-down mode, there is no need to go through
> the whole address space again for the bottom-up fallback: the goal of this
> fallback is to find, as a last resort, space between the top-down mmap base
> and the stack, which is the only place not covered by the top-down mmap.
>
> Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
> ---
>   arch/s390/mm/mmap.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
> index cbc718ba6d78..4a222969843b 100644
> --- a/arch/s390/mm/mmap.c
> +++ b/arch/s390/mm/mmap.c
> @@ -166,7 +166,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
>   	if (addr & ~PAGE_MASK) {
>   		VM_BUG_ON(addr != -ENOMEM);
>   		info.flags = 0;
> -		info.low_limit = TASK_UNMAPPED_BASE;
> +		info.low_limit = mm->mmap_base;
>   		info.high_limit = TASK_SIZE;
>   		addr = vm_unmapped_area(&info);
>   		if (addr & ~PAGE_MASK)