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

Message ID 20240817-mseal-depessimize-v3-3-d8d2e037df30@gmail.com
State Accepted
Commit 4a2dd02b09160ee43f96c759fafa7b56dfc33816
Headers show
Series mm: Optimize mseal checks | expand

Commit Message

Pedro Falcato Aug. 17, 2024, 12:18 a.m. UTC 
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>
---
 mm/mprotect.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

Comments

Liam R. Howlett Aug. 19, 2024, 8:33 p.m. UTC | #1 
* 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
>
diff mbox series

Patch

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;