The patch titled
Subject: ipc/shm, mm: drop do_vma_munmap()
has been added to the -mm mm-unstable branch. Its filename is
ipc-shm-mm-drop-do_vma_munmap.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ipc-shm-mm-drop-do_vma_munmap.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: ipc/shm, mm: drop do_vma_munmap()
Date: Thu, 22 Aug 2024 15:25:40 -0400
The do_vma_munmap() wrapper existed for callers that didn't have a vma
iterator and needed to check the vma mseal status prior to calling the
underlying munmap(). All callers now use a vma iterator and since the
mseal check has been moved to do_vmi_align_munmap() and the vmas are
aligned, this function can just be called instead.
do_vmi_align_munmap() can no longer be static as ipc/shm is using it and
it is exported via the mm.h header.
Link: https://lkml.kernel.org/r/20240822192543.3359552-19-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Bert Karwatzki <spasswolf@xxxxxx>
Cc: Jiri Olsa <olsajiri@xxxxxxxxx>
Cc: Kees Cook <kees@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 6 +++---
ipc/shm.c | 8 ++++----
mm/mmap.c | 33 ++++++---------------------------
mm/vma.c | 12 ++++++------
mm/vma.h | 4 +---
5 files changed, 20 insertions(+), 43 deletions(-)
--- a/include/linux/mm.h~ipc-shm-mm-drop-do_vma_munmap
+++ a/include/linux/mm.h
@@ -3287,14 +3287,14 @@ extern unsigned long do_mmap(struct file
extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
unsigned long start, size_t len, struct list_head *uf,
bool unlock);
+int do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
+ struct mm_struct *mm, unsigned long start,
+ unsigned long end, struct list_head *uf, bool unlock);
extern int do_munmap(struct mm_struct *, unsigned long, size_t,
struct list_head *uf);
extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior);
#ifdef CONFIG_MMU
-extern int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long start, unsigned long end,
- struct list_head *uf, bool unlock);
extern int __mm_populate(unsigned long addr, unsigned long len,
int ignore_errors);
static inline void mm_populate(unsigned long addr, unsigned long len)
--- a/ipc/shm.c~ipc-shm-mm-drop-do_vma_munmap
+++ a/ipc/shm.c
@@ -1778,8 +1778,8 @@ long ksys_shmdt(char __user *shmaddr)
*/
file = vma->vm_file;
size = i_size_read(file_inode(vma->vm_file));
- do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
- NULL, false);
+ do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start,
+ vma->vm_end, NULL, false);
/*
* We discovered the size of the shm segment, so
* break out of here and fall through to the next
@@ -1803,8 +1803,8 @@ long ksys_shmdt(char __user *shmaddr)
if ((vma->vm_ops == &shm_vm_ops) &&
((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
(vma->vm_file == file)) {
- do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
- NULL, false);
+ do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start,
+ vma->vm_end, NULL, false);
}
vma = vma_next(&vmi);
--- a/mm/mmap.c~ipc-shm-mm-drop-do_vma_munmap
+++ a/mm/mmap.c
@@ -169,11 +169,12 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
goto out; /* mapping intersects with an existing non-brk vma. */
/*
* mm->brk must be protected by write mmap_lock.
- * do_vma_munmap() will drop the lock on success, so update it
- * before calling do_vma_munmap().
+ * do_vmi_align_munmap() will drop the lock on success, so
+ * update it before calling do_vma_munmap().
*/
mm->brk = brk;
- if (do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true))
+ if (do_vmi_align_munmap(&vmi, brkvma, mm, newbrk, oldbrk, &uf,
+ /* unlock = */ true))
goto out;
goto success_unlocked;
@@ -1478,9 +1479,9 @@ cannot_expand:
vma->vm_file = get_file(file);
/*
* call_mmap() may map PTE, so ensure there are no existing PTEs
- * call the vm_ops close function if one exists.
+ * and call the vm_ops close function if one exists.
*/
- vms_clean_up_area(&vms, &mas_detach, true);
+ vms_clean_up_area(&vms, &mas_detach);
error = call_mmap(file, vma);
if (error)
goto unmap_and_free_vma;
@@ -1743,28 +1744,6 @@ out:
}
/*
- * do_vma_munmap() - Unmap a full or partial vma.
- * @vmi: The vma iterator pointing at the vma
- * @vma: The first vma to be munmapped
- * @start: the start of the address to unmap
- * @end: The end of the address to unmap
- * @uf: The userfaultfd list_head
- * @unlock: Drop the lock on success
- *
- * unmaps a VMA mapping when the vma iterator is already in position.
- * Does not handle alignment.
- *
- * Return: 0 on success drops the lock of so directed, error on failure and will
- * still hold the lock.
- */
-int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long start, unsigned long end, struct list_head *uf,
- bool unlock)
-{
- return do_vmi_align_munmap(vmi, vma, vma->vm_mm, start, end, uf, unlock);
-}
-
-/*
* do_brk_flags() - Increase the brk vma if the flags match.
* @vmi: The vma iterator
* @addr: The start address
--- a/mm/vma.c~ipc-shm-mm-drop-do_vma_munmap
+++ a/mm/vma.c
@@ -658,8 +658,8 @@ static inline void vms_clear_ptes(struct
*/
mas_set(mas_detach, 1);
lru_add_drain();
- tlb_gather_mmu(&tlb, vms->mm);
- update_hiwater_rss(vms->mm);
+ 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);
@@ -672,14 +672,14 @@ static inline void vms_clear_ptes(struct
}
void vms_clean_up_area(struct vma_munmap_struct *vms,
- struct ma_state *mas_detach, bool mm_wr_locked)
+ struct ma_state *mas_detach)
{
struct vm_area_struct *vma;
if (!vms->nr_pages)
return;
- vms_clear_ptes(vms, mas_detach, mm_wr_locked);
+ vms_clear_ptes(vms, mas_detach, true);
mas_set(mas_detach, 0);
mas_for_each(mas_detach, vma, ULONG_MAX)
if (vma->vm_ops && vma->vm_ops->close)
@@ -702,7 +702,7 @@ void vms_complete_munmap_vmas(struct vma
struct vm_area_struct *vma;
struct mm_struct *mm;
- mm = vms->mm;
+ mm = current->mm;
mm->map_count -= vms->vma_count;
mm->locked_vm -= vms->locked_vm;
if (vms->unlock)
@@ -770,7 +770,7 @@ int vms_gather_munmap_vmas(struct vma_mu
* its limit temporarily, to help free resources as expected.
*/
if (vms->end < vms->vma->vm_end &&
- vms->mm->map_count >= sysctl_max_map_count)
+ vms->vma->vm_mm->map_count >= sysctl_max_map_count)
goto map_count_exceeded;
/* Don't bother splitting the VMA if we can't unmap it anyway */
--- a/mm/vma.h~ipc-shm-mm-drop-do_vma_munmap
+++ a/mm/vma.h
@@ -31,7 +31,6 @@ struct unlink_vma_file_batch {
*/
struct vma_munmap_struct {
struct vma_iterator *vmi;
- struct mm_struct *mm;
struct vm_area_struct *vma; /* The first vma to munmap */
struct vm_area_struct *prev; /* vma before the munmap area */
struct vm_area_struct *next; /* vma after the munmap area */
@@ -113,7 +112,6 @@ static inline void init_vma_munmap(struc
unsigned long start, unsigned long end, struct list_head *uf,
bool unlock)
{
- vms->mm = current->mm;
vms->vmi = vmi;
vms->vma = vma;
if (vma) {
@@ -140,7 +138,7 @@ void vms_complete_munmap_vmas(struct vma
struct ma_state *mas_detach);
void vms_clean_up_area(struct vma_munmap_struct *vms,
- struct ma_state *mas_detach, bool mm_wr_locked);
+ struct ma_state *mas_detach);
/*
* reattach_vmas() - Undo any munmap work and free resources
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-remove-rcu_read_lock-from-mt_validate.patch
mm-vma-correctly-position-vma_iterator-in-__split_vma.patch
mm-vma-introduce-abort_munmap_vmas.patch
mm-vma-introduce-vmi_complete_munmap_vmas.patch
mm-vma-extract-the-gathering-of-vmas-from-do_vmi_align_munmap.patch
mm-vma-introduce-vma_munmap_struct-for-use-in-munmap-operations.patch
mm-vma-change-munmap-to-use-vma_munmap_struct-for-accounting-and-surrounding-vmas.patch
mm-vma-change-munmap-to-use-vma_munmap_struct-for-accounting-and-surrounding-vmas-fix.patch
mm-vma-extract-validate_mm-from-vma_complete.patch
mm-vma-inline-munmap-operation-in-mmap_region.patch
mm-vma-expand-mmap_region-munmap-call.patch
mm-vma-support-vma-==-null-in-init_vma_munmap.patch
mm-mmap-reposition-vma-iterator-in-mmap_region.patch
mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct.patch
mm-clean-up-unmap_region-argument-list.patch
mm-mmap-avoid-zeroing-vma-tree-in-mmap_region.patch
mm-change-failure-of-map_fixed-to-restoring-the-gap-on-failure.patch
mm-mmap-use-phys_pfn-in-mmap_region.patch
mm-mmap-use-vms-accounted-pages-in-mmap_region.patch
ipc-shm-mm-drop-do_vma_munmap.patch
mm-move-may_expand_vm-check-in-mmap_region.patch
mm-vma-drop-incorrect-comment-from-vms_gather_munmap_vmas.patch
mm-vmah-optimise-vma_munmap_struct.patch
