2020-06-17 02:23:30

by Souptick Joarder

Subject: [PATCH 2/4] staging: kpc2000: kpc_dma: Convert set_page_dirty() --> set_page_dirty_lock()

First, convert set_page_dirty() to set_page_dirty_lock()

Second, there is an interval in there after set_page_dirty() and
before put_page(), in which the device could be running and setting
pages dirty. Moving set_page_dirty_lock() after dma_unmap_sg().

Signed-off-by: Souptick Joarder <[email protected]>
Suggested-by: John Hubbard <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Bharath Vedartham <[email protected]>
---
drivers/staging/kpc2000/kpc_dma/fileops.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index b136353..bcce86c 100644
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -214,13 +214,13 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
BUG_ON(!acd->ldev);
BUG_ON(!acd->ldev->pldev);

+ dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
+
for (i = 0 ; i < acd->page_count ; i++) {
if (!PageReserved(acd->user_pages[i]))
- set_page_dirty(acd->user_pages[i]);
+ set_page_dirty_lock(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]);

--
1.9.1

2020-06-27 17:46:11

by Souptick Joarder

Subject: Re: [PATCH 2/4] staging: kpc2000: kpc_dma: Convert set_page_dirty() --> set_page_dirty_lock()

On Wed, Jun 17, 2020 at 7:50 AM Souptick Joarder <[email protected]> wrote:
>
> First, convert set_page_dirty() to set_page_dirty_lock()
>
> Second, there is an interval in there after set_page_dirty() and
> before put_page(), in which the device could be running and setting
> pages dirty. Moving set_page_dirty_lock() after dma_unmap_sg().
>
> Signed-off-by: Souptick Joarder <[email protected]>
> Suggested-by: John Hubbard <[email protected]>
> Cc: Dan Carpenter <[email protected]>
> Cc: Bharath Vedartham <[email protected]>
> ---
> drivers/staging/kpc2000/kpc_dma/fileops.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
> index b136353..bcce86c 100644
> --- a/drivers/staging/kpc2000/kpc_dma/fileops.c
> +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
> @@ -214,13 +214,13 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
> BUG_ON(!acd->ldev);
> BUG_ON(!acd->ldev->pldev);
>
> + dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
> +
> for (i = 0 ; i < acd->page_count ; i++) {
> if (!PageReserved(acd->user_pages[i]))

Question -> is PageReserved() used with specific purpose not PageDirty() ??

> - set_page_dirty(acd->user_pages[i]);
> + set_page_dirty_lock(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]);
>
> --
> 1.9.1
>