From 53bee98d004fcd7062f2fe056720704e947e6000 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Mon, 24 Jul 2023 14:31:48 -0400 Subject: [PATCH] mm: remove re-walk from mmap_region() 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@oracle.com Signed-off-by: Liam R. Howlett Cc: Peng Zhang Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- mm/internal.h | 8 ++++++++ mm/mmap.c | 15 ++++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 7d11ebe..c5ba08f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1041,6 +1041,14 @@ static inline bool vma_soft_dirty_enabled(struct vm_area_struct *vma) 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 */ diff --git a/mm/mmap.c b/mm/mmap.c index 5fbc7d7..a1a5948 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2676,8 +2676,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 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 *file, unsigned long addr, 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 *file, unsigned long addr, 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. -- 2.7.4