2022-03-29 06:59:13

by Fabio M. De Francesco

[permalink] [raw]
Subject: [PATCH v2] staging: rts5208: Convert kmap() to kmap_local_page()

The use of kmap() is being deprecated in favor of kmap_local_page()
where it is feasible.

With kmap_local_page(), the mapping is per thread, CPU local and not
globally visible. Therefore rtsx_stor_access_xfer_buf() is a function
where the use of kmap_local_page() in place of kmap() is correctly
suited.

Convert to kmap_local_page() but, instead of open coding it, use the
helpers memcpy_to_page() and memcpy_from_page().

Signed-off-by: Fabio M. De Francesco <[email protected]>
---

v1 -> v2: Rework the commit message and use the appropriate helpers
instead of open coding the use of kmap_local_page()/kunmap_local_page().
(Many thanks to Ira Weiny <[email protected]>).

drivers/staging/rts5208/rtsx_transport.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/rts5208/rtsx_transport.c b/drivers/staging/rts5208/rtsx_transport.c
index 805dc18fac0a..56b6cc845619 100644
--- a/drivers/staging/rts5208/rtsx_transport.c
+++ b/drivers/staging/rts5208/rtsx_transport.c
@@ -92,13 +92,11 @@ unsigned int rtsx_stor_access_xfer_buf(unsigned char *buffer,
while (sglen > 0) {
unsigned int plen = min(sglen, (unsigned int)
PAGE_SIZE - poff);
- unsigned char *ptr = kmap(page);

if (dir == TO_XFER_BUF)
- memcpy(ptr + poff, buffer + cnt, plen);
+ memcpy_to_page(page + poff, 0, buffer + cnt, plen);
else
- memcpy(buffer + cnt, ptr + poff, plen);
- kunmap(page);
+ memcpy_from_page(buffer + cnt, page + poff, 0, plen);

/* Start at the beginning of the next page */
poff = 0;
--
2.34.1


2022-03-29 11:38:18

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH v2] staging: rts5208: Convert kmap() to kmap_local_page()

On Tue, Mar 29, 2022 at 07:55:39AM +0200, Fabio M. De Francesco wrote:
> diff --git a/drivers/staging/rts5208/rtsx_transport.c b/drivers/staging/rts5208/rtsx_transport.c
> index 805dc18fac0a..56b6cc845619 100644
> --- a/drivers/staging/rts5208/rtsx_transport.c
> +++ b/drivers/staging/rts5208/rtsx_transport.c
> @@ -92,13 +92,11 @@ unsigned int rtsx_stor_access_xfer_buf(unsigned char *buffer,
> while (sglen > 0) {
> unsigned int plen = min(sglen, (unsigned int)
> PAGE_SIZE - poff);
> - unsigned char *ptr = kmap(page);
>
> if (dir == TO_XFER_BUF)
> - memcpy(ptr + poff, buffer + cnt, plen);
> + memcpy_to_page(page + poff, 0, buffer + cnt, plen);

You meant:

memcpy_to_page(page, poff, buffer + cnt, plen);

> else
> - memcpy(buffer + cnt, ptr + poff, plen);
> - kunmap(page);
> + memcpy_from_page(buffer + cnt, page + poff, 0, plen);

Same.

regards,
dan carpenter

2022-03-31 04:57:36

by Fabio M. De Francesco

[permalink] [raw]
Subject: Re: [PATCH v2] staging: rts5208: Convert kmap() to kmap_local_page()

On marted? 29 marzo 2022 11:18:27 CEST Dan Carpenter wrote:
> On Tue, Mar 29, 2022 at 07:55:39AM +0200, Fabio M. De Francesco wrote:
> > diff --git a/drivers/staging/rts5208/rtsx_transport.c b/drivers/staging/rts5208/rtsx_transport.c
> > index 805dc18fac0a..56b6cc845619 100644
> > --- a/drivers/staging/rts5208/rtsx_transport.c
> > +++ b/drivers/staging/rts5208/rtsx_transport.c
> > @@ -92,13 +92,11 @@ unsigned int rtsx_stor_access_xfer_buf(unsigned char *buffer,
> > while (sglen > 0) {
> > unsigned int plen = min(sglen, (unsigned int)
> > PAGE_SIZE - poff);
> > - unsigned char *ptr = kmap(page);
> >
> > if (dir == TO_XFER_BUF)
> > - memcpy(ptr + poff, buffer + cnt, plen);
> > + memcpy_to_page(page + poff, 0, buffer + cnt, plen);
>
> You meant:
>
> memcpy_to_page(page, poff, buffer + cnt, plen);
>

Yes, correct. I meant exactly what you wrote.

It's the first time that I use these API and, after 30 seconds look at their
prototypes, I thought that either have the same semantics.

I don't yet know if I'm wrong. However, even if either were correct, yours
would be more consistent and elegant. Therefore, I am going to change these
calls and submit a v3.

Thanks for your review,

Fabio M. De Francesco

> > else
> > - memcpy(buffer + cnt, ptr + poff, plen);
> > - kunmap(page);
> > + memcpy_from_page(buffer + cnt, page + poff, 0, plen);
>
> Same.
>
> regards,
> dan carpenter
>
>