[PATCH v1 8/9] mm/vma: Use unmap_desc in vms_clear_ptes() and exit_mmap()
Liam R. Howlett
Liam.Howlett at oracle.com
Tue Sep 9 12:09:44 PDT 2025
vms_clear_ptes() is slightly different than other callers to
unmap_region() and so had the unmapping open-coded. Using the new
structure it is now possible to special-case the struct setup instead of
having the open-coded function.
exit_mmap() also calls unmap_vmas() with many arguemnts. Using the
unmap_all_init() function to set the unmap descriptor for all vmas makes
this a bit easier to read.
Update to the vma test code is necessary to ensure testing continues to
function.
No functional changes intended.
Signed-off-by: Liam R. Howlett <Liam.Howlett at oracle.com>
---
include/linux/mm.h | 3 ---
mm/internal.h | 3 +++
mm/memory.c | 24 ++++++++------------
mm/mmap.c | 5 +++-
mm/vma.c | 39 ++++++++++++++++++--------------
mm/vma.h | 14 ++++++++++++
tools/testing/vma/vma_internal.h | 14 ++++--------
7 files changed, 56 insertions(+), 46 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 892fe5dbf9de0..23eb59d543390 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2450,9 +2450,6 @@ static inline void zap_vma_pages(struct vm_area_struct *vma)
zap_page_range_single(vma, vma->vm_start,
vma->vm_end - vma->vm_start, NULL);
}
-void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas,
- struct vm_area_struct *start_vma, unsigned long start,
- unsigned long end, unsigned long tree_end, bool mm_wr_locked);
struct mmu_notifier_range;
diff --git a/mm/internal.h b/mm/internal.h
index d295252407fee..1239944f2830a 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -197,6 +197,9 @@ static inline void vma_close(struct vm_area_struct *vma)
}
}
+/* unmap_vmas is in mm/memory.c */
+void unmap_vmas(struct mmu_gather *tlb, struct unmap_desc *unmap);
+
#ifdef CONFIG_MMU
/* Flags for folio_pte_batch(). */
diff --git a/mm/memory.c b/mm/memory.c
index 829cd94950182..8d4d976311037 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2084,12 +2084,7 @@ static void unmap_single_vma(struct mmu_gather *tlb,
/**
* unmap_vmas - unmap a range of memory covered by a list of vma's
* @tlb: address of the caller's struct mmu_gather
- * @mas: the maple state
- * @vma: the starting vma
- * @start_addr: virtual address at which to start unmapping
- * @end_addr: virtual address at which to end unmapping
- * @tree_end: The maximum index to check
- * @mm_wr_locked: lock flag
+ * @unmap: The unmap_desc
*
* Unmap all pages in the vma list.
*
@@ -2102,11 +2097,9 @@ static void unmap_single_vma(struct mmu_gather *tlb,
* ensure that any thus-far unmapped pages are flushed before unmap_vmas()
* drops the lock and schedules.
*/
-void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas,
- struct vm_area_struct *vma, unsigned long start_addr,
- unsigned long end_addr, unsigned long tree_end,
- bool mm_wr_locked)
+void unmap_vmas(struct mmu_gather *tlb, struct unmap_desc *unmap)
{
+ struct vm_area_struct *vma;
struct mmu_notifier_range range;
struct zap_details details = {
.zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP,
@@ -2114,17 +2107,18 @@ void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas,
.even_cows = true,
};
+ vma = unmap->first;
mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma->vm_mm,
- start_addr, end_addr);
+ unmap->vma_min, unmap->vma_max);
mmu_notifier_invalidate_range_start(&range);
do {
- unsigned long start = start_addr;
- unsigned long end = end_addr;
+ unsigned long start = unmap->vma_min;
+ unsigned long end = unmap->vma_max;
hugetlb_zap_begin(vma, &start, &end);
unmap_single_vma(tlb, vma, start, end, &details,
- mm_wr_locked);
+ unmap->mm_wr_locked);
hugetlb_zap_end(vma, &details);
- vma = mas_find(mas, tree_end - 1);
+ vma = mas_find(unmap->mas, unmap->tree_max - 1);
} while (vma);
mmu_notifier_invalidate_range_end(&range);
}
diff --git a/mm/mmap.c b/mm/mmap.c
index 5c9bd3f20e53f..6011f62b0a294 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1280,10 +1280,12 @@ void exit_mmap(struct mm_struct *mm)
struct vm_area_struct *vma;
unsigned long nr_accounted = 0;
VMA_ITERATOR(vmi, mm, 0);
+ struct unmap_desc unmap;
/* mm's last user has gone, and its about to be pulled down */
mmu_notifier_release(mm);
+ unmap.mm_wr_locked = false;
mmap_read_lock(mm);
arch_exit_mmap(mm);
@@ -1295,11 +1297,12 @@ void exit_mmap(struct mm_struct *mm)
goto destroy;
}
+ unmap_all_init(&unmap, &vmi, vma);
flush_cache_mm(mm);
tlb_gather_mmu_fullmm(&tlb, mm);
/* update_hiwater_rss(mm) here? but nobody should be looking */
/* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */
- unmap_vmas(&tlb, &vmi.mas, vma, 0, ULONG_MAX, ULONG_MAX, false);
+ unmap_vmas(&tlb, &unmap);
mmap_read_unlock(mm);
/*
diff --git a/mm/vma.c b/mm/vma.c
index c92384975cbb2..ad64cd9795ef3 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -481,8 +481,7 @@ void unmap_region(struct unmap_desc *desc)
tlb_gather_mmu(&tlb, mm);
update_hiwater_rss(mm);
- unmap_vmas(&tlb, mas, desc->first, desc->vma_min, desc->vma_max,
- desc->vma_max, desc->mm_wr_locked);
+ unmap_vmas(&tlb, desc);
mas_set(mas, desc->tree_reset);
free_pgtables(&tlb, mas, desc->first, desc->first_pgaddr,
desc->last_pgaddr, desc->tree_max,
@@ -1213,26 +1212,32 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
static inline void vms_clear_ptes(struct vma_munmap_struct *vms,
struct ma_state *mas_detach, bool mm_wr_locked)
{
- struct mmu_gather tlb;
+ struct unmap_desc unmap = {
+ .mas = mas_detach,
+ .first = vms->vma,
+ /* start and end may be different if there is no prev or next vma. */
+ .first_pgaddr = vms->unmap_start,
+ .last_pgaddr = vms->unmap_end,
+ .vma_min = vms->start,
+ .vma_max = vms->end,
+ /*
+ * The tree limits and reset differ from the normal case since it's a
+ * side-tree
+ */
+ .tree_reset = 1,
+ .tree_max = vms->vma_count,
+ /*
+ * We can free page tables without write-locking mmap_lock because VMAs
+ * were isolated before we downgraded mmap_lock.
+ */
+ .mm_wr_locked = mm_wr_locked,
+ };
if (!vms->clear_ptes) /* Nothing to do */
return;
- /*
- * We can free page tables without write-locking mmap_lock because VMAs
- * were isolated before we downgraded mmap_lock.
- */
mas_set(mas_detach, 1);
- tlb_gather_mmu(&tlb, vms->vma->vm_mm);
- update_hiwater_rss(vms->vma->vm_mm);
- unmap_vmas(&tlb, mas_detach, vms->vma, vms->start, vms->end,
- vms->vma_count, mm_wr_locked);
-
- mas_set(mas_detach, 1);
- /* start and end may be different if there is no prev or next vma. */
- free_pgtables(&tlb, mas_detach, vms->vma, vms->unmap_start,
- vms->unmap_end, vms->unmap_end, mm_wr_locked);
- tlb_finish_mmu(&tlb);
+ unmap_region(&unmap);
vms->clear_ptes = false;
}
diff --git a/mm/vma.h b/mm/vma.h
index 4edd5d26ffcfc..8b55a0c73d097 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -164,6 +164,20 @@ struct unmap_desc {
bool mm_wr_locked; /* If the mmap write lock is held */
};
+static inline void unmap_all_init(struct unmap_desc *desc,
+ struct vma_iterator *vmi, struct vm_area_struct *vma)
+{
+ desc->mas = &vmi->mas;
+ desc->first = vma;
+ desc->first_pgaddr = FIRST_USER_ADDRESS;
+ desc->last_pgaddr = USER_PGTABLES_CEILING;
+ desc->vma_min = 0;
+ desc->vma_max = ULONG_MAX;
+ desc->tree_max = ULONG_MAX;
+ desc->tree_reset = vma->vm_end;
+ desc->mm_wr_locked = false;
+}
+
#define UNMAP_REGION(name, _vmi, _vma, _vma_min, _vma_max, _prev, _next) \
struct unmap_desc name = { \
.mas = &(_vmi)->mas, \
diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index 823d379e1fac2..d73ad4747d40a 100644
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -884,18 +884,12 @@ static inline void update_hiwater_vm(struct mm_struct *)
{
}
-static inline void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas,
- struct vm_area_struct *vma, unsigned long start_addr,
- unsigned long end_addr, unsigned long tree_end,
- bool mm_wr_locked)
+struct unmap_desc;
+
+static inline void unmap_vmas(struct mmu_gather *tlb, struct unmap_desc *unmap)
{
(void)tlb;
- (void)mas;
- (void)vma;
- (void)start_addr;
- (void)end_addr;
- (void)tree_end;
- (void)mm_wr_locked;
+ (void)unmap;
}
static inline void free_pgtables(struct mmu_gather *tlb, struct ma_state *mas,
--
2.47.2
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