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Message-ID: <20240710192250.4114783-20-Liam.Howlett@oracle.com>
Date: Wed, 10 Jul 2024 15:22:48 -0400
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
To: linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>
Cc: Suren Baghdasaryan <surenb@...gle.com>, Vlastimil Babka <vbabka@...e.cz>,
Lorenzo Stoakes <lstoakes@...il.com>,
Matthew Wilcox <willy@...radead.org>, sidhartha.kumar@...cle.com,
"Paul E . McKenney" <paulmck@...nel.org>,
Bert Karwatzki <spasswolf@....de>, Jiri Olsa <olsajiri@...il.com>,
linux-kernel@...r.kernel.org, Kees Cook <kees@...nel.org>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: [PATCH v4 19/21] ipc/shm, mm: Drop do_vma_munmap()
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
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 of can_modify_mm() 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.
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
include/linux/mm.h | 6 +++---
ipc/shm.c | 8 ++++----
mm/mmap.c | 33 +++++----------------------------
3 files changed, 12 insertions(+), 35 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e2140ea6ae98..40f1db1fb233 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3400,14 +3400,14 @@ 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);
+extern 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)
diff --git a/ipc/shm.c b/ipc/shm.c
index 3e3071252dac..99564c870084 100644
--- a/ipc/shm.c
+++ b/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);
diff --git a/mm/mmap.c b/mm/mmap.c
index c343366b3ad2..18c269bf8703 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -268,11 +268,12 @@ 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;
@@ -2837,7 +2838,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
* Return: 0 on success and drops the lock if so directed, error and leaves the
* lock held otherwise.
*/
-static int
+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)
@@ -3319,30 +3320,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
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)
-{
- struct mm_struct *mm = vma->vm_mm;
-
- return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, unlock);
-}
-
/*
* do_brk_flags() - Increase the brk vma if the flags match.
* @vmi: The vma iterator
--
2.43.0
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