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SubjectRE: [PATCH RESEND] rapidio: use get_user_pages_unlocked()
Date
Acked-by: Alexandre Bounine <alexandre.bounine@idt.com>

> -----Original Message-----
> From: Lorenzo Stoakes [mailto:lstoakes@gmail.com]
> Sent: Tuesday, January 03, 2017 3:50 PM
> To: Matt Porter; Bounine, Alexandre
> Cc: linux-mm@kvack.org; linux-kernel@vger.kernel.org; Andrew Morton;
> Lorenzo Stoakes
> Subject: [PATCH RESEND] rapidio: use get_user_pages_unlocked()
>
> Moving from get_user_pages() to get_user_pages_unlocked() simplifies
> the code
> and takes advantage of VM_FAULT_RETRY functionality when faulting in
> pages.
>
> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
> ---
> drivers/rapidio/devices/rio_mport_cdev.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/rapidio/devices/rio_mport_cdev.c
> b/drivers/rapidio/devices/rio_mport_cdev.c
> index 9013a585507e..50b617af81bd 100644
> --- a/drivers/rapidio/devices/rio_mport_cdev.c
> +++ b/drivers/rapidio/devices/rio_mport_cdev.c
> @@ -889,17 +889,16 @@ rio_dma_transfer(struct file *filp, u32
> transfer_mode,
> goto err_req;
> }
>
> - down_read(&current->mm->mmap_sem);
> - pinned = get_user_pages(
> + pinned = get_user_pages_unlocked(
> (unsigned long)xfer->loc_addr & PAGE_MASK,
> nr_pages,
> - dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
> - page_list, NULL);
> - up_read(&current->mm->mmap_sem);
> + page_list,
> + dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0);
>
> if (pinned != nr_pages) {
> if (pinned < 0) {
> - rmcd_error("get_user_pages err=%ld", pinned);
> + rmcd_error("get_user_pages_unlocked err=%ld",
> + pinned);
> nr_pages = 0;
> } else
> rmcd_error("pinned %ld out of %ld pages",
> --
> 2.11.0

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