The patch titled
Subject: mm: remove re-walk from mmap_region()
has been added to the -mm mm-unstable branch. Its filename is
mm-remove-re-walk-from-mmap_region.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-remove-re-walk-from-mmap_region.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: remove re-walk from mmap_region()
Date: Mon, 24 Jul 2023 14:31:48 -0400
Using vma_iter_set() will reset the tree and cause a re-walk. Use
vmi_iter_config() to set the write to a sub-set of the range. Change
the file case to also use vmi_iter_config() so that the end is correctly
set.
Link: https://lkml.kernel.org/r/20230724183157.3939892-7-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/internal.h | 8 ++++++++
mm/mmap.c | 15 ++++++++++-----
2 files changed, 18 insertions(+), 5 deletions(-)
--- a/mm/internal.h~mm-remove-re-walk-from-mmap_region
+++ a/mm/internal.h
@@ -1041,6 +1041,14 @@ static inline bool vma_soft_dirty_enable
return !(vma->vm_flags & VM_SOFTDIRTY);
}
+static inline void vma_iter_config(struct vma_iterator *vmi,
+ unsigned long index, unsigned long last)
+{
+ MAS_BUG_ON(&vmi->mas, vmi->mas.node != MAS_START &&
+ (vmi->mas.index > index || vmi->mas.last < index));
+ __mas_set_range(&vmi->mas, index, last - 1);
+}
+
/*
* VMA Iterator functions shared between nommu and mmap
*/
--- a/mm/mmap.c~mm-remove-re-walk-from-mmap_region
+++ a/mm/mmap.c
@@ -2676,8 +2676,11 @@ unsigned long mmap_region(struct file *f
next = vma_next(&vmi);
prev = vma_prev(&vmi);
- if (vm_flags & VM_SPECIAL)
+ if (vm_flags & VM_SPECIAL) {
+ if (prev)
+ vma_iter_next_range(&vmi);
goto cannot_expand;
+ }
/* Attempt to expand an old mapping */
/* Check next */
@@ -2698,6 +2701,8 @@ unsigned long mmap_region(struct file *f
merge_start = prev->vm_start;
vma = prev;
vm_pgoff = prev->vm_pgoff;
+ } else if (prev) {
+ vma_iter_next_range(&vmi);
}
@@ -2708,9 +2713,9 @@ unsigned long mmap_region(struct file *f
goto expanded;
}
+ if (vma == prev)
+ vma_iter_set(&vmi, addr);
cannot_expand:
- if (prev)
- vma_iter_next_range(&vmi);
/*
* Determine the object being mapped and call the appropriate
@@ -2723,7 +2728,7 @@ cannot_expand:
goto unacct_error;
}
- vma_iter_set(&vmi, addr);
+ vma_iter_config(&vmi, addr, end);
vma->vm_start = addr;
vma->vm_end = end;
vm_flags_init(vma, vm_flags);
@@ -2750,7 +2755,7 @@ cannot_expand:
if (WARN_ON((addr != vma->vm_start)))
goto close_and_free_vma;
- vma_iter_set(&vmi, addr);
+ vma_iter_config(&vmi, addr, end);
/*
* If vm_flags changed after call_mmap(), we should try merge
* vma again as we may succeed this time.
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
mm-mmap-clean-up-validate_mm-calls.patch
maple_tree-relax-lockdep-checks-for-on-stack-trees.patch
mm-mmap-change-detached-vma-locking-scheme.patch
maple_tree-be-more-strict-about-locking.patch
maple_tree-add-benchmarking-for-mas_for_each.patch
maple_tree-add-benchmarking-for-mas_prev.patch
mm-change-do_vmi_align_munmap-tracking-of-vmas-to-remove.patch
mm-remove-prev-check-from-do_vmi_align_munmap.patch
maple_tree-introduce-__mas_set_range.patch
mm-remove-re-walk-from-mmap_region.patch
maple_tree-re-introduce-entry-to-mas_preallocate-arguments.patch
maple_tree-adjust-node-allocation-on-mas_rebalance.patch
mm-use-vma_iter_clear_gfp-in-nommu.patch
mm-set-up-vma-iterator-for-vma_iter_prealloc-calls.patch
maple_tree-move-mas_wr_end_piv-below-mas_wr_extend_null.patch
maple_tree-update-mas_preallocate-testing.patch
maple_tree-refine-mas_preallocate-node-calculations.patch
maple_tree-reduce-resets-during-store-setup.patch
mm-mmap-change-vma-iteration-order-in-do_vmi_align_munmap.patch
