lkml.org 
[lkml]   [2023]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 17/33] mm/mremap: write-lock VMA while remapping it to a new address range
On Mon, Feb 27, 2023 at 09:36:16AM -0800, Suren Baghdasaryan wrote:
> Write-lock VMA as locked before copying it and when copy_vma produces
> a new VMA.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Reviewed-by: Laurent Dufour <laurent.dufour@fr.ibm.com>
> ---
> mm/mmap.c | 1 +
> mm/mremap.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index e73fbb84ce12..1f42b9a52b9b 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3189,6 +3189,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
> get_file(new_vma->vm_file);
> if (new_vma->vm_ops && new_vma->vm_ops->open)
> new_vma->vm_ops->open(new_vma);
> + vma_start_write(new_vma);

Oh, it's to prevent handling page faults during move_page_tables().


> if (vma_link(mm, new_vma))
> goto out_vma_link;
> *need_rmap_locks = false;
> diff --git a/mm/mremap.c b/mm/mremap.c
> index 1ddf7beb62e9..327c38eb132e 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -623,6 +623,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
> return -ENOMEM;
> }
>
> + vma_start_write(vma);
> new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
> new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
> &need_rmap_locks);
> --
> 2.39.2.722.g9855ee24e9-goog

Looks good to me.

Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

>
>

\
 
 \ /
  Last update: 2023-03-27 00:39    [W:0.212 / U:2.596 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site