Re: [PATCH v2 02/13] mm/vma: update do_mmap() to use vma_flags_t

[Vlastimil Babka (SUSE)]

On 7/11/26 20:44, Lorenzo Stoakes wrote:
> The core do_mmap() function accepts a vm_flags_t parameter which it then
> manipulates before passing to mmap_region() to do the heavy lifting of the
> memory mapping.
> 
> Update do_mmap() to instead accept a vma_flags_t parameter, and adjust all
> the logic within do_mmap() to manipulate this instead.
> 
> This is as part of the ongoing effort to convert VMA flags from a system
> word size to a bitmap type which allows us to unrestrict the number of VMA
> flags, as well as gain control over how VMA flag manipulation occurs.
> 
> We do not cascade these changes to all functions which accept vm_flags_t,
> but rather use vma_flags_to_legacy() where necessary, specifically
> deferring converting calc_vm_prot_bits(), calc_vm_flag_bits() and
> __get_unmapped_area() to vma_flags_t.
> 
> Also utilise the new vma_flags_can_grow() predicate which correctly handles
> the case of architectures without upward growing stacks.
> 
> As part of this change, introduce VMA_SHADOW_STACK so we can correctly
> handle the case of the shadow stack not being defined.
> 
> No functional change intended.
> 
> Reviewed-by: Lance Yang <lance.yang@xxxxxxxxx>
> Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
> Signed-off-by: Lorenzo Stoakes <ljs@xxxxxxxxxx>

Reviewed-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>