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From: David Hildenbrand <[email protected]>
To: Lorenzo Stoakes <[email protected]>,
	[email protected], [email protected],
	Andrew Morton <[email protected]>
Cc: Matthew Wilcox <[email protected]>,
	Jens Axboe <[email protected]>,
	Pavel Begunkov <[email protected]>,
	[email protected]
Subject: Re: [PATCH v4 4/6] io_uring: rsrc: avoid use of vmas parameter in pin_user_pages()
Date: Tue, 18 Apr 2023 17:55:48 +0200	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <956f4fc2204f23e4c00e9602ded80cb4e7b5df9b.1681831798.git.lstoakes@gmail.com>

On 18.04.23 17:49, Lorenzo Stoakes wrote:
> We are shortly to remove pin_user_pages(), and instead perform the required
> VMA checks ourselves. In most cases there will be a single VMA so this
> should caues no undue impact on an already slow path.
> 
> Doing this eliminates the one instance of vmas being used by
> pin_user_pages().
> 
> Suggested-by: Matthew Wilcox (Oracle) <[email protected]>
> Signed-off-by: Lorenzo Stoakes <[email protected]>
> ---
>   io_uring/rsrc.c | 55 ++++++++++++++++++++++++++++---------------------
>   1 file changed, 31 insertions(+), 24 deletions(-)
> 
> diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
> index 7a43aed8e395..3a927df9d913 100644
> --- a/io_uring/rsrc.c
> +++ b/io_uring/rsrc.c
> @@ -1138,12 +1138,37 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
>   	return ret;
>   }
>   
> +static int check_vmas_locked(unsigned long addr, unsigned long len)

TBH, the whole "_locked" suffix is a bit confusing.

I was wondering why you'd want to check whether the VMAs are locked ...

> +{
> +	struct file *file;
> +	VMA_ITERATOR(vmi, current->mm, addr);
> +	struct vm_area_struct *vma = vma_next(&vmi);
> +	unsigned long end = addr + len;
> +
> +	if (WARN_ON_ONCE(!vma))
> +		return -EINVAL;
> +
> +	file = vma->vm_file;
> +	if (file && !is_file_hugepages(file))
> +		return -EOPNOTSUPP;

You'd now be rejecting vma_is_shmem() here, no?


-- 
Thanks,

David / dhildenb


  reply	other threads:[~2023-04-18 15:56 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <[email protected]>
2023-04-18 15:49 ` [PATCH v4 4/6] io_uring: rsrc: avoid use of vmas parameter in pin_user_pages() Lorenzo Stoakes
2023-04-18 15:55   ` David Hildenbrand [this message]
2023-04-18 15:56     ` David Hildenbrand
2023-04-18 16:25     ` Lorenzo Stoakes
2023-04-19 16:35   ` Jens Axboe
2023-04-19 16:59     ` Jens Axboe
2023-04-19 17:23       ` Lorenzo Stoakes
2023-04-19 17:35         ` Jens Axboe
2023-04-19 17:47           ` Lorenzo Stoakes
2023-04-19 17:51             ` Jens Axboe
2023-04-19 18:18               ` Lorenzo Stoakes
2023-04-19 18:22                 ` Jason Gunthorpe
2023-04-19 18:50                   ` Lorenzo Stoakes
2023-04-19 18:23                 ` Matthew Wilcox
2023-04-19 18:24                   ` Jason Gunthorpe
2023-04-19 18:35                     ` Matthew Wilcox
2023-04-19 18:45                       ` Lorenzo Stoakes
2023-04-19 23:22                         ` Jason Gunthorpe
2023-04-20 13:57                           ` Lorenzo Stoakes
2023-04-20 13:36                       ` Pavel Begunkov
2023-04-20 14:19                         ` Lorenzo Stoakes
2023-04-20 15:31                           ` Jason Gunthorpe
2023-04-19 20:15                     ` Jens Axboe
2023-04-19 20:18                       ` Jens Axboe
2023-04-20 13:37                       ` Pavel Begunkov
2023-04-19 17:07     ` Lorenzo Stoakes
2023-04-18 15:49 ` [PATCH v4 5/6] mm/gup: remove vmas parameter from pin_user_pages() Lorenzo Stoakes

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