| Message ID | 20221123205219.31748-5-anirudh.venkataramanan@intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | e3128591b55a009558cfb5e1df99b719eb60ce62 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Remove uses of kmap_atomic() | expand |
On mercoledì 23 novembre 2022 21:52:17 CET Anirudh Venkataramanan wrote: > kmap_atomic() is being deprecated in favor of kmap_local_page(). Replace > the map-memcpy-unmap usage pattern (done using k[un]map_atomic()) with > memcpy_from_page(), which internally uses kmap_local_page() and > kunmap_local(). This renders the variable 'vaddr' unnecessary, and so > remove this too. > > Note that kmap_atomic() disables preemption and page-fault processing, but > kmap_local_page() doesn't. When converting uses of kmap_atomic(), one has > to check if the code being executed between the map/unmap implicitly > depends on page-faults and/or preemption being disabled. If yes, then code > to disable page-faults and/or preemption should also be added for > functional correctness. That however doesn't appear to be the case here, > so just memcpy_from_page() is used. > > Also note that the page being mapped is not allocated by the driver, and so > the driver doesn't know if the page is in normal memory. This is the reason > kmap_local_page() is used (via memcpy_from_page()) as opposed to > page_address(). > > I don't have hardware, so this change has only been compile tested. > > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com> > Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> > Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com> > --- > v1 -> v2: > Use memcpy_from_page() as suggested by Fabio > Add a "Suggested-by" tag > Rework commit message > --- > drivers/net/ethernet/sun/cassini.c | 14 ++++---------- > 1 file changed, 4 insertions(+), 10 deletions(-) Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Thanks, Fabio > diff --git a/drivers/net/ethernet/sun/cassini.c > b/drivers/net/ethernet/sun/cassini.c index 2f66cfc..4ef05ba 100644 > --- a/drivers/net/ethernet/sun/cassini.c > +++ b/drivers/net/ethernet/sun/cassini.c > @@ -90,8 +90,6 @@ > #include <linux/uaccess.h> > #include <linux/jiffies.h> > > -#define cas_page_map(x) kmap_atomic((x)) > -#define cas_page_unmap(x) kunmap_atomic((x)) > #define CAS_NCPUS num_online_cpus() > > #define cas_skb_release(x) netif_rx(x) > @@ -2781,18 +2779,14 @@ static inline int cas_xmit_tx_ringN(struct cas *cp, > int ring, > > tabort = cas_calc_tabort(cp, skb_frag_off(fragp), len); > if (unlikely(tabort)) { > - void *addr; > - > /* NOTE: len is always > tabort */ > cas_write_txd(cp, ring, entry, mapping, len - tabort, > ctrl, 0); > entry = TX_DESC_NEXT(ring, entry); > - > - addr = cas_page_map(skb_frag_page(fragp)); > - memcpy(tx_tiny_buf(cp, ring, entry), > - addr + skb_frag_off(fragp) + len - tabort, > - tabort); > - cas_page_unmap(addr); > + memcpy_from_page(tx_tiny_buf(cp, ring, entry), > + skb_frag_page(fragp), > + skb_frag_off(fragp) + len - tabort, > + tabort); > mapping = tx_tiny_map(cp, ring, entry, tentry); > len = tabort; > } > -- > 2.37.2
diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c index 2f66cfc..4ef05ba 100644 --- a/drivers/net/ethernet/sun/cassini.c +++ b/drivers/net/ethernet/sun/cassini.c @@ -90,8 +90,6 @@ #include <linux/uaccess.h> #include <linux/jiffies.h> -#define cas_page_map(x) kmap_atomic((x)) -#define cas_page_unmap(x) kunmap_atomic((x)) #define CAS_NCPUS num_online_cpus() #define cas_skb_release(x) netif_rx(x) @@ -2781,18 +2779,14 @@ static inline int cas_xmit_tx_ringN(struct cas *cp, int ring, tabort = cas_calc_tabort(cp, skb_frag_off(fragp), len); if (unlikely(tabort)) { - void *addr; - /* NOTE: len is always > tabort */ cas_write_txd(cp, ring, entry, mapping, len - tabort, ctrl, 0); entry = TX_DESC_NEXT(ring, entry); - - addr = cas_page_map(skb_frag_page(fragp)); - memcpy(tx_tiny_buf(cp, ring, entry), - addr + skb_frag_off(fragp) + len - tabort, - tabort); - cas_page_unmap(addr); + memcpy_from_page(tx_tiny_buf(cp, ring, entry), + skb_frag_page(fragp), + skb_frag_off(fragp) + len - tabort, + tabort); mapping = tx_tiny_map(cp, ring, entry, tentry); len = tabort; }
kmap_atomic() is being deprecated in favor of kmap_local_page(). Replace the map-memcpy-unmap usage pattern (done using k[un]map_atomic()) with memcpy_from_page(), which internally uses kmap_local_page() and kunmap_local(). This renders the variable 'vaddr' unnecessary, and so remove this too. Note that kmap_atomic() disables preemption and page-fault processing, but kmap_local_page() doesn't. When converting uses of kmap_atomic(), one has to check if the code being executed between the map/unmap implicitly depends on page-faults and/or preemption being disabled. If yes, then code to disable page-faults and/or preemption should also be added for functional correctness. That however doesn't appear to be the case here, so just memcpy_from_page() is used. Also note that the page being mapped is not allocated by the driver, and so the driver doesn't know if the page is in normal memory. This is the reason kmap_local_page() is used (via memcpy_from_page()) as opposed to page_address(). I don't have hardware, so this change has only been compile tested. Cc: Ira Weiny <ira.weiny@intel.com> Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com> Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com> --- v1 -> v2: Use memcpy_from_page() as suggested by Fabio Add a "Suggested-by" tag Rework commit message --- drivers/net/ethernet/sun/cassini.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)