Re: [PATCH v6 15/24] fs/io_uring: set FOLL_PIN via pin_user_pages()

[John Hubbard]

On 11/19/19 8:10 AM, Jens Axboe wrote:
> On 11/19/19 1:16 AM, John Hubbard wrote:
>> Convert fs/io_uring to use the new pin_user_pages() call, which sets
>> FOLL_PIN. Setting FOLL_PIN is now required for code that requires
>> tracking of pinned pages, and therefore for any code that calls
>> put_user_page().
>>
>> In partial anticipation of this work, the io_uring code was already
>> calling put_user_page() instead of put_page(). Therefore, in order to
>> convert from the get_user_pages()/put_page() model, to the
>> pin_user_pages()/put_user_page() model, the only change required
>> here is to change get_user_pages() to pin_user_pages().
>>
>> Reviewed-by: Jan Kara 
>> Signed-off-by: John Hubbard 
> 
> You dropped my reviewed-by now... Given the file, you'd probably want
> to keep that.

Hi Jens,

Yes, I was being too conservative I guess. I changed the patch somewhat
and dropped the reviewed-by because of those changes...I'm adding it
back for v7 based on this, thanks!

thanks,
-- 
John Hubbard
NVIDIA
 
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[PATCH v6 15/24] fs/io_uring: set FOLL_PIN via pin_user_pages()

[John Hubbard]

Convert fs/io_uring to use the new pin_user_pages() call, which sets
FOLL_PIN. Setting FOLL_PIN is now required for code that requires
tracking of pinned pages, and therefore for any code that calls
put_user_page().

In partial anticipation of this work, the io_uring code was already
calling put_user_page() instead of put_page(). Therefore, in order to
convert from the get_user_pages()/put_page() model, to the
pin_user_pages()/put_user_page() model, the only change required
here is to change get_user_pages() to pin_user_pages().

Reviewed-by: Jan Kara 
Signed-off-by: John Hubbard 
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2c819c3c855d..15715eeebaec 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3449,7 +3449,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx 
*ctx, void __user *arg,
 
ret = 0;
down_read(>mm->mmap_sem);
-   pret = get_user_pages(ubuf, nr_pages,
+   pret = pin_user_pages(ubuf, nr_pages,
  FOLL_WRITE | FOLL_LONGTERM,
  pages, vmas);
if (pret == nr_pages) {
-- 
2.24.0

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