Re: [RFC v10 PATCH 1/3] mm: mmap: zap pages with read mmap_sem in munmap

From: Matthew Wilcox
Date: Sat Sep 15 2018 - 05:24:18 EST


On Sat, Sep 15, 2018 at 04:34:57AM +0800, Yang Shi wrote:
> Suggested-by: Michal Hocko <mhocko@xxxxxxxxxx>
> Suggested-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
> Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>

Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>

Looks good! Thanks for sticking with this patch series.

Minor spelling fixes:

> - /*
> - * Remove the vma's, and unmap the actual pages
> - */
> + /* Detatch vmas from rbtree */

"Detach"

> + /*
> + * mpx unmap need to be handled with write mmap_sem. It is safe to
> + * deal with it before unmap_region().
> + */

* mpx unmap needs to be called with mmap_sem held for write.
* It is safe to call it before unmap_region()

> + ret = __do_munmap(mm, start, len, &uf, downgrade);
> + /*
> + * Returning 1 indicates mmap_sem is down graded.
> + * But 1 is not legal return value of vm_munmap() and munmap(), reset
> + * it to 0 before return.
> + */

"downgraded" is one word.