linux-kernel - Re: [PATCH] staging: kpc2000: Convert put_page() to put_user

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Date:   Mon, 15 Jul 2019 15:04:11 -0700
From:   John Hubbard <jhubbard@...dia.com>
To:     Matt Sickler <Matt.Sickler@...tronics.com>,
        Bharath Vedartham <linux.bhar@...il.com>,
        "ira.weiny@...el.com" <ira.weiny@...el.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "jglisse@...hat.com" <jglisse@...hat.com>
CC:     "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging: kpc2000: Convert put_page() to put_user_page*()

On 7/15/19 3:01 PM, John Hubbard wrote:
> On 7/15/19 2:47 PM, Matt Sickler wrote:
...
> I agree: the PageReserved check looks unnecessary here, from my outside-the-kpc_2000-team
> perspective, anyway. Assuming that your analysis above is correct, you could collapse that
> whole think into just:
> 
> @@ -211,17 +209,8 @@ void  transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
>         BUG_ON(acd->ldev == NULL);
>         BUG_ON(acd->ldev->pldev == NULL);
>  
> -       for (i = 0 ; i < acd->page_count ; i++) {
> -               if (!PageReserved(acd->user_pages[i])) {
> -                       set_page_dirty(acd->user_pages[i]);
> -               }
> -       }
> -
>         dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
> -
> -       for (i = 0 ; i < acd->page_count ; i++) {
> -               put_page(acd->user_pages[i]);
> -       }
> +       put_user_pages_dirty(&acd->user_pages[i], acd->page_count);

Ahem, I typed too quickly. :) Please make that:

    put_user_pages_dirty(acd->user_pages, acd->page_count);

thanks,
-- 
John Hubbard
NVIDIA