On Tue, Mar 29, 2022 at 06:20:55PM +0200, Fabio M. De Francesco wrote:
> 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 <fmdefrancesco@xxxxxxxxx>
> ---
>
> v1 -> v2: Rework the commit message and use the appropriate helpers
> instead of open coding the use of kmap_local_page()/kunmap_local_page().
> (Thanks to Ira Weiny <ira.weiny@xxxxxxxxx>).
>
> v2 -> v3: Use memcpy_{to,from}_page() arguments correctly.
> (Thanks to Dan Carpenter <dan.carpenter@xxxxxxxxxx>).
>
> 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..b702c7caf944 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, buffer + cnt, plen);
> else
> - memcpy(buffer + cnt, ptr + poff, plen);
> - kunmap(page);
> + memcpy_from_page(buffer + cnt, page, poff, plen);
This code is great... But I went and looked at the function and found a
comment which needs to be updated as well. :-/
57 /*
58 * Using scatter-gather. We have to go through the list one entry
59 * at a time. Each s-g entry contains some number of pages, and
60 * each page has to be kmap()'ed separately.
61 */
I would update it to say something like:
... Each s-g entry contains some number of pages which have to be copied one
at a time.
Sorry for not catching that earlier,
Ira
>
> /* Start at the beginning of the next page */
> poff = 0;
> --
> 2.34.1
>
