| Message ID | 20221117222557.2196195-5-anirudh.venkataramanan@intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Remove uses of kmap_atomic() | expand |
On giovedì 17 novembre 2022 23:25:56 CET Anirudh Venkataramanan wrote: > kmap_atomic() is being deprecated in favor of kmap_local_page(). > Replace kmap_atomic() and kunmap_atomic() with kmap_local_page() and > kunmap_local() respectively. cas_page_map() and cas_page_unmap() aren't > really useful anymore, so get rid of these as well. > > Note that kmap_atomic() disables preemption and page-fault processing, > but kmap_local_page() doesn't. Converting the former to the latter is safe > only if there isn't an implicit dependency on preemption and page-fault > handling being disabled, which does appear to be the case here. Same NIT: again, conversions would be possible with the addition of explicit call(s) for disable page faults and preemption. As I said, I have no problems with this inaccurate description. Please see 2/5, I don't think it should prevent the patch to be applied. > > 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 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> > Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com> > --- > drivers/net/ethernet/sun/cassini.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/sun/cassini.c > b/drivers/net/ethernet/sun/cassini.c index 2f66cfc..3e632b0 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) > @@ -2788,11 +2786,11 @@ static inline int cas_xmit_tx_ringN(struct cas *cp, > int ring, ctrl, 0); > entry = TX_DESC_NEXT(ring, entry); > > - addr = cas_page_map(skb_frag_page(fragp)); > + addr = kmap_local_page(skb_frag_page(fragp)); > memcpy(tx_tiny_buf(cp, ring, entry), > addr + skb_frag_off(fragp) + len - tabort, > tabort); > - cas_page_unmap(addr); > + kunmap_local(addr); memcpy_from_page() would be better suited. Please remember to use memcpy_{from,to}_page() where they are better suited. However, they would not change the logic, so I'm OK with this change too. > mapping = tx_tiny_map(cp, ring, entry, tentry); > len = tabort; > } > -- > 2.37.2 Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Feel free to forward my tag, if maintainers require the use of the above- mentioned helpers and ask for v2. Thanks, Fabio
diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c index 2f66cfc..3e632b0 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) @@ -2788,11 +2786,11 @@ static inline int cas_xmit_tx_ringN(struct cas *cp, int ring, ctrl, 0); entry = TX_DESC_NEXT(ring, entry); - addr = cas_page_map(skb_frag_page(fragp)); + addr = kmap_local_page(skb_frag_page(fragp)); memcpy(tx_tiny_buf(cp, ring, entry), addr + skb_frag_off(fragp) + len - tabort, tabort); - cas_page_unmap(addr); + kunmap_local(addr); mapping = tx_tiny_map(cp, ring, entry, tentry); len = tabort; }
kmap_atomic() is being deprecated in favor of kmap_local_page(). Replace kmap_atomic() and kunmap_atomic() with kmap_local_page() and kunmap_local() respectively. cas_page_map() and cas_page_unmap() aren't really useful anymore, so get rid of these as well. Note that kmap_atomic() disables preemption and page-fault processing, but kmap_local_page() doesn't. Converting the former to the latter is safe only if there isn't an implicit dependency on preemption and page-fault handling being disabled, which does appear to be the case here. 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 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> Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com> --- drivers/net/ethernet/sun/cassini.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)