The patch titled
Subject: mmap: clean up mmap_region() unrolling
has been added to the -mm mm-unstable branch. Its filename is
mmap-clean-up-mmap_region-unrolling.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mmap-clean-up-mmap_region-unrolling.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: mmap: clean up mmap_region() unrolling
Date: Thu, 5 Jan 2023 19:16:02 +0000
Move logic of unrolling to the error path as apposed to duplicating it
within the function body. This reduces the potential of missing an
update to one path when making changes.
Link: https://lkml.kernel.org/r/20230105191517.3099082-34-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Li Zetao <lizetao1@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 47 +++++++++++++++++++----------------------------
1 file changed, 19 insertions(+), 28 deletions(-)
--- a/mm/mmap.c~mmap-clean-up-mmap_region-unrolling
+++ a/mm/mmap.c
@@ -2663,12 +2663,11 @@ cannot_expand:
* Expansion is handled above, merging is handled below.
* Drivers should not alter the address of the VMA.
*/
- if (WARN_ON((addr != vma->vm_start))) {
- error = -EINVAL;
+ error = -EINVAL;
+ if (WARN_ON((addr != vma->vm_start)))
goto close_and_free_vma;
- }
- vma_iter_set(&vmi, addr);
+ vma_iter_set(&vmi, addr);
/*
* If vm_flags changed after call_mmap(), we should try merge
* vma again as we may succeed this time.
@@ -2705,25 +2704,13 @@ cannot_expand:
}
/* Allow architectures to sanity-check the vm_flags */
- if (!arch_validate_flags(vma->vm_flags)) {
- error = -EINVAL;
- if (file)
- goto close_and_free_vma;
- else if (vma->vm_file)
- goto unmap_and_free_vma;
- else
- goto free_vma;
- }
-
- if (vma_iter_prealloc(&vmi, vma)) {
- error = -ENOMEM;
- if (file)
- goto close_and_free_vma;
- else if (vma->vm_file)
- goto unmap_and_free_vma;
- else
- goto free_vma;
- }
+ error = -EINVAL;
+ if (!arch_validate_flags(vma->vm_flags))
+ goto close_and_free_vma;
+
+ error = -ENOMEM;
+ if (vma_iter_prealloc(&vmi, vma))
+ goto close_and_free_vma;
if (vma->vm_file)
i_mmap_lock_write(vma->vm_file->f_mapping);
@@ -2782,14 +2769,18 @@ expanded:
return addr;
close_and_free_vma:
- if (vma->vm_ops && vma->vm_ops->close)
+ if (file && vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
+
+ if (file || vma->vm_file) {
unmap_and_free_vma:
- fput(vma->vm_file);
- vma->vm_file = NULL;
+ fput(vma->vm_file);
+ vma->vm_file = NULL;
- /* Undo any partial mapping done by a device driver. */
- unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end);
+ /* Undo any partial mapping done by a device driver. */
+ unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start,
+ vma->vm_end);
+ }
if (file && (vm_flags & VM_SHARED))
mapping_unmap_writable(file->f_mapping);
free_vma:
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-add-mas_init-function.patch
maple_tree-fix-potential-rcu-issue.patch
maple_tree-reduce-user-error-potential.patch
test_maple_tree-test-modifications-while-iterating.patch
mm-expand-vma-iterator-interface.patch
mm-mmap-convert-brk-to-use-vma-iterator.patch
kernel-fork-convert-forking-to-using-the-vmi-iterator.patch
mmap-convert-vma_link-vma-iterator.patch
mm-mmap-remove-preallocation-from-do_mas_align_munmap.patch
mmap-change-do_mas_munmap-and-do_mas_aligned_munmap-to-use-vma-iterator.patch
mmap-convert-vma_expand-to-use-vma-iterator.patch
mm-add-temporary-vma-iterator-versions-of-vma_merge-split_vma-and-__split_vma.patch
ipc-shm-use-the-vma-iterator-for-munmap-calls.patch
userfaultfd-use-vma-iterator.patch
mm-change-mprotect_fixup-to-vma-iterator.patch
mlock-convert-mlock-to-vma-iterator.patch
coredump-convert-to-vma-iterator.patch
mempolicy-convert-to-vma-iterator.patch
task_mmu-convert-to-vma-iterator.patch
sched-convert-to-vma-iterator.patch
madvise-use-vmi-iterator-for-__split_vma-and-vma_merge.patch
mmap-pass-through-vmi-iterator-to-__split_vma.patch
mmap-use-vmi-version-of-vma_merge.patch
mm-mremap-use-vmi-version-of-vma_merge.patch
mm-switch-vma_merge-split_vma-and-__split_vma-to-vma-iterator.patch
mmap-convert-__vma_adjust-to-use-vma-iterator.patch
mm-pass-through-vma-iterator-to-__vma_adjust.patch
madvise-use-split_vma-instead-of-__split_vma.patch
mm-remove-unnecessary-write-to-vma-iterator-in-__vma_adjust.patch
mm-pass-vma-iterator-through-to-__vma_adjust.patch
mm-add-vma-iterator-to-vma_adjust-arguments.patch
mmap-clean-up-mmap_region-unrolling.patch
mm-change-munmap-splitting-order-and-move_vma.patch
mm-mmap-move-anon_vma-setting-in-__vma_adjust.patch
mm-mmap-refactor-locking-out-of-__vma_adjust.patch
mm-mmap-use-vma_prepare-and-vma_complete-in-vma_expand.patch
mm-mmap-introduce-init_vma_prep-and-init_multi_vma_prep.patch
mm-dont-use-__vma_adjust-in-__split_vma.patch
mm-mmap-dont-use-__vma_adjust-in-shift_arg_pages.patch
mm-mmap-introduce-dup_vma_anon-helper.patch
mm-mmap-convert-do_brk_flags-to-use-vma_prepare-and-vma_complete.patch
mm-mmap-remove-__vma_adjust.patch
vma_merge-set-vma-iterator-to-correct-position.patch
