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Message-ID: <362d3286-07d3-43c7-84f6-1dfb6c2bbae6@lucifer.local>
Date: Thu, 11 Jul 2024 15:16:35 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: "Liam R. Howlett" <Liam.Howlett@...cle.com>
Cc: linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
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>
Subject: Re: [PATCH v4 09/21] mm/mmap: Expand mmap_region() munmap call
On Wed, Jul 10, 2024 at 03:22:38PM GMT, Liam R. Howlett wrote:
> From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
>
> Open code the do_vmi_align_munmap() call so that it can be broken up
> later in the series.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
> ---
> mm/mmap.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 49b3ab406353..a1544a68558e 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2916,6 +2916,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> struct vm_area_struct *next, *prev, *merge;
> pgoff_t pglen = len >> PAGE_SHIFT;
> unsigned long charged = 0;
> + struct vma_munmap_struct vms;
> + struct ma_state mas_detach;
> + struct maple_tree mt_detach;
> unsigned long end = addr + len;
> unsigned long merge_start = addr, merge_end = end;
> bool writable_file_mapping = false;
> @@ -2948,10 +2951,27 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> /* Find the first overlapping VMA */
> vma = vma_find(&vmi, end);
> if (vma) {
> - /* Unmap any existing mapping in the area */
> - if (do_vmi_align_munmap(&vmi, vma, mm, addr, end, uf, false))
> + mt_init_flags(&mt_detach, vmi.mas.tree->ma_flags & MT_FLAGS_LOCK_MASK);
> + mt_on_stack(mt_detach);
> + mas_init(&mas_detach, &mt_detach, /* addr = */ 0);
> + init_vma_munmap(&vms, &vmi, vma, addr, end, uf, /* unlock = */ false);
> + /* Prepare to unmap any existing mapping in the area */
> + if (vms_gather_munmap_vmas(&vms, &mas_detach))
> + return -ENOMEM;
> +
> + /* Remove any existing mappings from the vma tree */
> + if (vma_iter_clear_gfp(&vmi, addr, end, GFP_KERNEL))
> return -ENOMEM;
> +
> + /* Unmap any existing mapping in the area */
> + vms_complete_munmap_vmas(&vms, &mas_detach);
> + next = vms.next;
> + prev = vms.prev;
> + vma_prev(&vmi);
> vma = NULL;
> + } else {
> + next = vma_next(&vmi);
> + prev = vma_prev(&vmi);
> }
>
> /*
> @@ -2964,8 +2984,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> vm_flags |= VM_ACCOUNT;
> }
>
> - next = vma_next(&vmi);
> - prev = vma_prev(&vmi);
> if (vm_flags & VM_SPECIAL) {
> if (prev)
> vma_iter_next_range(&vmi);
> --
> 2.43.0
>
LGTM
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
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