Re: [PATCH v2 5/7] fs/proc/task_mmu.c: simplify the vma_stop() logic

[Kirill A. Shutemov]

On Tue, Aug 05, 2014 at 09:46:59PM +0200, Oleg Nesterov wrote:
> m_start() drops ->mmap_sem and does mmput() if it retuns vsyscall
> vma. This is because in this case m_stop()->vma_stop() obviously
> can't use gate_vma->vm_mm.
> 
> Now that we have proc_maps_private->mm we can simplify this logic:
> 
>   - Change m_start() to return with ->mmap_sem held unless it returns
>     IS_ERR_OR_NULL().
> 
>   - Change vma_stop() to use priv->mm and avoid the ugly vma checks,
>     this makes "vm_area_struct *vma" unnecessary.
> 
>   - This also allows m_start() to use vm_stop().
> 
>   - Cleanup m_next() to follow the new locking rule.
> 
>     Note: m_stop() looks very ugly, and this temporary uglifies it
>     even more. Fixed by the next change.
> 
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

-- 
 Kirill A. Shutemov
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