The patch titled
Subject: mm/mremap: remove goto from mremap_to()
has been added to the -mm mm-unstable branch. Its filename is
mm-mremap-remove-goto-from-mremap_to.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mremap-remove-goto-from-mremap_to.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: mm/mremap: remove goto from mremap_to()
Date: Fri, 18 Oct 2024 13:41:14 -0400
mremap_to() has a goto label at the end that doesn't unwind anything.
Removing the label makes the code cleaner.
This commit also adds documentation to the function.
Link: https://lkml.kernel.org/r/20241018174114.2871880-3-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jeff Xu <jeffxu@xxxxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 46 +++++++++++++++++++++++++++-------------------
1 file changed, 27 insertions(+), 19 deletions(-)
--- a/mm/mremap.c~mm-mremap-remove-goto-from-mremap_to
+++ a/mm/mremap.c
@@ -887,6 +887,20 @@ static int resize_is_valid(struct vm_are
return 0;
}
+/*
+ * mremap_to() - remap a vma to a new location
+ * @addr: The old address
+ * @old_len: The old size
+ * @new_addr: The target address
+ * @new_len: The new size
+ * @locked: If the returned vma is locked (VM_LOCKED)
+ * @flags: the mremap flags
+ * @uf: The mremap userfaultfd context
+ * @uf_unmap_early: The userfaultfd unmap early context
+ * @uf_unmap: The userfaultfd unmap context
+ *
+ * Returns: The new address of the vma or an error.
+ */
static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
unsigned long new_addr, unsigned long new_len, bool *locked,
unsigned long flags, struct vm_userfaultfd_ctx *uf,
@@ -895,18 +909,18 @@ static unsigned long mremap_to(unsigned
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- unsigned long ret = -EINVAL;
+ unsigned long ret;
unsigned long map_flags = 0;
if (offset_in_page(new_addr))
- goto out;
+ return -EINVAL;
if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
- goto out;
+ return -EINVAL;
/* Ensure the old/new locations do not overlap */
if (addr + old_len > new_addr && new_addr + new_len > addr)
- goto out;
+ return -EINVAL;
/*
* move_vma() need us to stay 4 maps below the threshold, otherwise
@@ -933,31 +947,28 @@ static unsigned long mremap_to(unsigned
*/
ret = do_munmap(mm, new_addr, new_len, uf_unmap_early);
if (ret)
- goto out;
+ return ret;
}
if (old_len > new_len) {
ret = do_munmap(mm, addr+new_len, old_len - new_len, uf_unmap);
if (ret)
- goto out;
+ return ret;
old_len = new_len;
}
vma = vma_lookup(mm, addr);
- if (!vma) {
- ret = -EFAULT;
- goto out;
- }
+ if (!vma)
+ return -EFAULT;
ret = resize_is_valid(vma, addr, old_len, new_len, flags);
if (ret)
- goto out;
+ return ret;
/* MREMAP_DONTUNMAP expands by old_len since old_len == new_len */
if (flags & MREMAP_DONTUNMAP &&
!may_expand_vm(mm, vma->vm_flags, old_len >> PAGE_SHIFT)) {
- ret = -ENOMEM;
- goto out;
+ return -ENOMEM;
}
if (flags & MREMAP_FIXED)
@@ -970,17 +981,14 @@ static unsigned long mremap_to(unsigned
((addr - vma->vm_start) >> PAGE_SHIFT),
map_flags);
if (IS_ERR_VALUE(ret))
- goto out;
+ return ret;
/* We got a new mapping */
if (!(flags & MREMAP_FIXED))
new_addr = ret;
- ret = move_vma(vma, addr, old_len, new_len, new_addr, locked, flags, uf,
- uf_unmap);
-
-out:
- return ret;
+ return move_vma(vma, addr, old_len, new_len, new_addr, locked, flags,
+ uf, uf_unmap);
}
static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
mm-mmap-fix-race-in-mmap_region-with-ftrucate.patch
mm-mremap-clean-up-vma_to_resize.patch
mm-mremap-remove-goto-from-mremap_to.patch
