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ipc/shm, mm: drop do_vma_munmap()

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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/20240830040101.822209-19-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2024-08-30 00:00:58 -04:00 committed by Andrew Morton
parent 13d77e0133
commit 63fc66f5b6
5 changed files with 20 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/mm.h
View File

@ -3287,14 +3287,14 @@ extern unsigned long do_mmap(struct file *file, unsigned long addr,
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)

8
ipc/shm.c
View File

@ -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);

33
mm/mmap.c
View File

@ -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;
@ -1479,9 +1480,9 @@ 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;
@ -1744,28 +1745,6 @@ out:
return ret;
}
/*
* 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

12
mm/vma.c
View File

@ -658,8 +658,8 @@ static inline void vms_clear_ptes(struct vma_munmap_struct *vms,
*/
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 vma_munmap_struct *vms,
}
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_munmap_struct *vms,
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_munmap_struct *vms,
* 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 */

4
mm/vma.h
View File

@ -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 */
@ -114,7 +113,6 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms,
unsigned long start, unsigned long end, struct list_head *uf,
bool unlock)
{
vms->mm = current->mm;
vms->vmi = vmi;
vms->vma = vma;
if (vma) {
@ -142,7 +140,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
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