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Message-ID: <20240820235730.2852400-10-Liam.Howlett@oracle.com>
Date: Tue, 20 Aug 2024 19:57:18 -0400
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Suren Baghdasaryan <surenb@...gle.com>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
Matthew Wilcox <willy@...radead.org>, Vlastimil Babka <vbabka@...e.cz>,
sidhartha.kumar@...cle.com, Bert Karwatzki <spasswolf@....de>,
Jiri Olsa <olsajiri@...il.com>, Kees Cook <kees@...nel.org>,
"Paul E . McKenney" <paulmck@...nel.org>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: [PATCH v6 09/20] mm/vma: Expand mmap_region() munmap call
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
Open code the do_vmi_align_munmap() call so that it can be broken up
later in the series.
This requires exposing a few more vma operations.
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
---
mm/mmap.c | 26 ++++++++++++++++++++++----
mm/vma.c | 31 ++-----------------------------
mm/vma.h | 33 +++++++++++++++++++++++++++++++++
3 files changed, 57 insertions(+), 33 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 0f5be29d48b6..e7e6bf09b558 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1366,6 +1366,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
struct vm_area_struct *next, *prev, *merge;
pgoff_t pglen = len >> PAGE_SHIFT;
unsigned long charged = 0;
+ struct vma_munmap_struct vms;
+ struct ma_state mas_detach;
+ struct maple_tree mt_detach;
unsigned long end = addr + len;
unsigned long merge_start = addr, merge_end = end;
bool writable_file_mapping = false;
@@ -1391,10 +1394,27 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* Find the first overlapping VMA */
vma = vma_find(&vmi, end);
if (vma) {
- /* Unmap any existing mapping in the area */
- if (do_vmi_align_munmap(&vmi, vma, mm, addr, end, uf, false))
+ mt_init_flags(&mt_detach, vmi.mas.tree->ma_flags & MT_FLAGS_LOCK_MASK);
+ mt_on_stack(mt_detach);
+ mas_init(&mas_detach, &mt_detach, /* addr = */ 0);
+ init_vma_munmap(&vms, &vmi, vma, addr, end, uf, /* unlock = */ false);
+ /* Prepare to unmap any existing mapping in the area */
+ if (vms_gather_munmap_vmas(&vms, &mas_detach))
+ return -ENOMEM;
+
+ /* Remove any existing mappings from the vma tree */
+ if (vma_iter_clear_gfp(&vmi, addr, end, GFP_KERNEL))
return -ENOMEM;
+
+ /* Unmap any existing mapping in the area */
+ vms_complete_munmap_vmas(&vms, &mas_detach);
+ next = vms.next;
+ prev = vms.prev;
+ vma_prev(&vmi);
vma = NULL;
+ } else {
+ next = vma_next(&vmi);
+ prev = vma_prev(&vmi);
}
/*
@@ -1407,8 +1427,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vm_flags |= VM_ACCOUNT;
}
- next = vma_next(&vmi);
- prev = vma_prev(&vmi);
if (vm_flags & VM_SPECIAL) {
if (prev)
vma_iter_next_range(&vmi);
diff --git a/mm/vma.c b/mm/vma.c
index 5abda4c49c83..2840cbaeff8b 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -80,33 +80,6 @@ static void init_multi_vma_prep(struct vma_prepare *vp,
}
-/*
- * init_vma_munmap() - Initializer wrapper for vma_munmap_struct
- * @vms: The vma munmap struct
- * @vmi: The vma iterator
- * @vma: The first vm_area_struct to munmap
- * @start: The aligned start address to munmap
- * @end: The aligned end address to munmap
- * @uf: The userfaultfd list_head
- * @unlock: Unlock after the operation. Only unlocked on success
- */
-static inline void init_vma_munmap(struct vma_munmap_struct *vms,
- struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long start, unsigned long end, struct list_head *uf,
- bool unlock)
-{
- vms->vmi = vmi;
- vms->vma = vma;
- vms->mm = vma->vm_mm;
- vms->start = start;
- vms->end = end;
- vms->unlock = unlock;
- vms->uf = uf;
- vms->vma_count = 0;
- vms->nr_pages = vms->locked_vm = vms->nr_accounted = 0;
- vms->exec_vm = vms->stack_vm = vms->data_vm = 0;
-}
-
/*
* Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
* in front of (at a lower virtual address and file offset than) the vma.
@@ -698,7 +671,7 @@ static inline void abort_munmap_vmas(struct ma_state *mas_detach)
* used for the munmap() and may downgrade the lock - if requested. Everything
* needed to be done once the vma maple tree is updated.
*/
-static void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
+void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach)
{
struct vm_area_struct *vma;
@@ -747,7 +720,7 @@ static void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
*
* Return: 0 on success
*/
-static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
+int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
struct ma_state *mas_detach)
{
struct vm_area_struct *next = NULL;
diff --git a/mm/vma.h b/mm/vma.h
index cbf55e0e0c4f..e78b24d1cf83 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -78,6 +78,39 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long start, unsigned long end, pgoff_t pgoff);
+/*
+ * init_vma_munmap() - Initializer wrapper for vma_munmap_struct
+ * @vms: The vma munmap struct
+ * @vmi: The vma iterator
+ * @vma: The first vm_area_struct to munmap
+ * @start: The aligned start address to munmap
+ * @end: The aligned end address to munmap
+ * @uf: The userfaultfd list_head
+ * @unlock: Unlock after the operation. Only unlocked on success
+ */
+static inline void init_vma_munmap(struct vma_munmap_struct *vms,
+ struct vma_iterator *vmi, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end, struct list_head *uf,
+ bool unlock)
+{
+ vms->vmi = vmi;
+ vms->vma = vma;
+ vms->mm = vma->vm_mm;
+ vms->start = start;
+ vms->end = end;
+ vms->unlock = unlock;
+ vms->uf = uf;
+ vms->vma_count = 0;
+ vms->nr_pages = vms->locked_vm = vms->nr_accounted = 0;
+ vms->exec_vm = vms->stack_vm = vms->data_vm = 0;
+}
+
+int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
+ struct ma_state *mas_detach);
+
+void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
+ struct ma_state *mas_detach);
+
int
do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct mm_struct *mm, unsigned long start,
--
2.43.0
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