Messages in this thread | | | Date | Tue, 29 Mar 2022 22:34:51 -0700 | From | Ira Weiny <> | Subject | Re: [PATCHi v3] staging: rts5208: Convert kmap() to kmap_local_page() |
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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@gmail.com> > --- > > 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@intel.com>). > > v2 -> v3: Use memcpy_{to,from}_page() arguments correctly. > (Thanks to Dan Carpenter <dan.carpenter@oracle.com>). > > 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 >
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