Re: [PATCH v3 3/7] mm/mprotect: Replace can_modify_mm with can_modify_vma

* Pedro Falcato pedro.falcato@gmail.com [240816 20:19]:

Avoid taking an extra trip down the mmap tree by checking the vmas directly. mprotect (per POSIX) tolerates partial failure.

Signed-off-by: Pedro Falcato pedro.falcato@gmail.com

Reviewed-by: Liam R. Howlett Liam.Howlett@Oracle.com

---

mm/mprotect.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c index 446f8e5f10d9..0c5d6d06107d 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -611,6 +611,9 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, unsigned long charged = 0; int error;

• if (!can_modify_vma(vma))

• return -EPERM;
  

• if (newflags == oldflags) { *pprev = vma; return 0;

@@ -769,15 +772,6 @@ static int do_mprotect_pkey(unsigned long start, size_t len, } }

• /*

• * checking if memory is sealed.
  

• * can_modify_mm assumes we have acquired the lock on MM.
  

• */
  

• if (unlikely(!can_modify_mm(current->mm, start, end))) {

• error = -EPERM;
  

• goto out;
  

• }
• prev = vma_prev(&vmi); if (start > vma->vm_start) prev = vma;

-- 2.46.0