linux-kernel - [PATCH v3 3/5] mm/mseal: small cleanups

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Message-ID: <ac51c2a3c68a2475149b54180ff012fffab72c02.1752687069.git.lorenzo.stoakes@oracle.com>
Date: Wed, 16 Jul 2025 18:38:04 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "Liam R . Howlett" <Liam.Howlett@...cle.com>,
        David Hildenbrand <david@...hat.com>, Vlastimil Babka <vbabka@...e.cz>,
        Jann Horn <jannh@...gle.com>, Pedro Falcato <pfalcato@...e.de>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Jeff Xu <jeffxu@...omium.org>
Subject: [PATCH v3 3/5] mm/mseal: small cleanups

Drop the wholly unnecessary set_vma_sealed() helper(), which is used only
once, and place VMA_ITERATOR() declarations in the correct place.

Retain vma_is_sealed(), and use it instead of the confusingly named
can_modify_vma(), so it's abundantly clear what's being tested, rather then
a nebulous sense of 'can the VMA be modified'.

No functional change intended.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Reviewed-by: Pedro Falcato <pfalcato@...e.de>
Acked-by: David Hildenbrand <david@...hat.com>
---
 mm/madvise.c  |  2 +-
 mm/mprotect.c |  2 +-
 mm/mremap.c   |  2 +-
 mm/mseal.c    |  9 +--------
 mm/vma.c      |  4 ++--
 mm/vma.h      | 20 ++------------------
 6 files changed, 8 insertions(+), 31 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index dc3d8497b0f4..da6e0e7c00b5 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1286,7 +1286,7 @@ static bool can_madvise_modify(struct madvise_behavior *madv_behavior)
 	struct vm_area_struct *vma = madv_behavior->vma;
 
 	/* If the VMA isn't sealed we're good. */
-	if (can_modify_vma(vma))
+	if (!vma_is_sealed(vma))
 		return true;
 
 	/* For a sealed VMA, we only care about discard operations. */
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 88709c01177b..807939177065 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -605,7 +605,7 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
 	unsigned long charged = 0;
 	int error;
 
-	if (!can_modify_vma(vma))
+	if (vma_is_sealed(vma))
 		return -EPERM;
 
 	if (newflags == oldflags) {
diff --git a/mm/mremap.c b/mm/mremap.c
index 5b7fe8f36074..8e93eca86721 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1649,7 +1649,7 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
 		return -EFAULT;
 
 	/* If mseal()'d, mremap() is prohibited. */
-	if (!can_modify_vma(vma))
+	if (vma_is_sealed(vma))
 		return -EPERM;
 
 	/* Align to hugetlb page size, if required. */
diff --git a/mm/mseal.c b/mm/mseal.c
index 1308e88ab184..adbcc65e9660 100644
--- a/mm/mseal.c
+++ b/mm/mseal.c
@@ -15,11 +15,6 @@
 #include <linux/sched.h>
 #include "internal.h"
 
-static inline void set_vma_sealed(struct vm_area_struct *vma)
-{
-	vm_flags_set(vma, VM_SEALED);
-}
-
 static int mseal_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		struct vm_area_struct **prev, unsigned long start,
 		unsigned long end, vm_flags_t newflags)
@@ -36,7 +31,7 @@ static int mseal_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		goto out;
 	}
 
-	set_vma_sealed(vma);
+	vm_flags_set(vma, VM_SEALED);
 out:
 	*prev = vma;
 	return ret;
@@ -53,7 +48,6 @@ static int check_mm_seal(unsigned long start, unsigned long end)
 {
 	struct vm_area_struct *vma;
 	unsigned long nstart = start;
-
 	VMA_ITERATOR(vmi, current->mm, start);
 
 	/* going through each vma to check. */
@@ -78,7 +72,6 @@ static int apply_mm_seal(unsigned long start, unsigned long end)
 {
 	unsigned long nstart;
 	struct vm_area_struct *vma, *prev;
-
 	VMA_ITERATOR(vmi, current->mm, start);
 
 	vma = vma_iter_load(&vmi);
diff --git a/mm/vma.c b/mm/vma.c
index fc502b741dcf..75fd2759964b 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -1351,7 +1351,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
 		}
 
 		/* Don't bother splitting the VMA if we can't unmap it anyway */
-		if (!can_modify_vma(vms->vma)) {
+		if (vma_is_sealed(vms->vma)) {
 			error = -EPERM;
 			goto start_split_failed;
 		}
@@ -1371,7 +1371,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
 	for_each_vma_range(*(vms->vmi), next, vms->end) {
 		long nrpages;
 
-		if (!can_modify_vma(next)) {
+		if (vma_is_sealed(next)) {
 			error = -EPERM;
 			goto modify_vma_failed;
 		}
diff --git a/mm/vma.h b/mm/vma.h
index 85db5e880fcc..b123a9cdedb0 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -559,31 +559,15 @@ struct vm_area_struct *vma_iter_next_rewind(struct vma_iterator *vmi,
 }
 
 #ifdef CONFIG_64BIT
-
 static inline bool vma_is_sealed(struct vm_area_struct *vma)
 {
 	return (vma->vm_flags & VM_SEALED);
 }
-
-/*
- * check if a vma is sealed for modification.
- * return true, if modification is allowed.
- */
-static inline bool can_modify_vma(struct vm_area_struct *vma)
-{
-	if (unlikely(vma_is_sealed(vma)))
-		return false;
-
-	return true;
-}
-
 #else
-
-static inline bool can_modify_vma(struct vm_area_struct *vma)
+static inline bool vma_is_sealed(struct vm_area_struct *vma)
 {
-	return true;
+	return false;
 }
-
 #endif
 
 #if defined(CONFIG_STACK_GROWSUP)
-- 
2.50.1