| Message ID | 20250220020914.895431-7-almasrymina@google.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Device memory TCP TX | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next, async |
| netdev/apply | fail | Patch does not apply to net-next-0 |
On 02/20, Mina Almasry wrote: > Drivers need to make sure not to pass netmem dma-addrs to the > dma-mapping API in order to support netmem TX. > > Add helpers and netmem_dma_*() helpers that enables special handling of > netmem dma-addrs that drivers can use. > > Document in netmem.rst what drivers need to do to support netmem TX. > > Signed-off-by: Mina Almasry <almasrymina@google.com> > > --- > > v4: > - New patch > --- > .../networking/net_cachelines/net_device.rst | 1 + > Documentation/networking/netdev-features.rst | 5 +++++ > Documentation/networking/netmem.rst | 14 +++++++++++-- > include/linux/netdevice.h | 2 ++ > include/net/netmem.h | 20 +++++++++++++++++++ > 5 files changed, 40 insertions(+), 2 deletions(-) > > diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst > index 15e31ece675f..e3043b033647 100644 > --- a/Documentation/networking/net_cachelines/net_device.rst > +++ b/Documentation/networking/net_cachelines/net_device.rst > @@ -10,6 +10,7 @@ Type Name fastpath_tx_acce > =================================== =========================== =================== =================== =================================================================================== > unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx) > unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx) > +unsigned long:1 netmem_tx:1; read_mostly > char name[16] > struct netdev_name_node* name_node > struct dev_ifalias* ifalias > diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst > index 5014f7cc1398..02bd7536fc0c 100644 > --- a/Documentation/networking/netdev-features.rst > +++ b/Documentation/networking/netdev-features.rst > @@ -188,3 +188,8 @@ Redundancy) frames from one port to another in hardware. > This should be set for devices which duplicate outgoing HSR (High-availability > Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically > frames in hardware. > + > +* netmem-tx > + > +This should be set for devices which support netmem TX. See > +Documentation/networking/netmem.rst > diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst > index 7de21ddb5412..43054d44c407 100644 > --- a/Documentation/networking/netmem.rst > +++ b/Documentation/networking/netmem.rst > @@ -19,8 +19,8 @@ Benefits of Netmem : > * Simplified Development: Drivers interact with a consistent API, > regardless of the underlying memory implementation. > > -Driver Requirements > -=================== > +Driver RX Requirements > +====================== > > 1. The driver must support page_pool. > > @@ -77,3 +77,13 @@ Driver Requirements > that purpose, but be mindful that some netmem types might have longer > circulation times, such as when userspace holds a reference in zerocopy > scenarios. > + > +Driver TX Requirements > +====================== > + > +1. Driver should use netmem_dma_unmap_page_attrs() in lieu of > + dma_unmap_page[_attrs](), and netmem_dma_unmap_addr_set() in lieu of > + dma_unmap_addr_set(). The netmem variants will handle netmems that should > + not be dma-unmapped by the driver, such as dma-buf netmems. Not all drivers use dma_unmap_addr_xxx APIs (looking at mlx5). Might be worth mentioning that for the drivers managing the mappings differently, care might be taken to not unmap netmems? > +2. Driver should declare support by setting `netdev->netmem_tx = true` > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index fccc03cd2164..d8cfd5d69ddf 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1753,6 +1753,7 @@ enum netdev_reg_state { > * @lltx: device supports lockless Tx. Deprecated for real HW > * drivers. Mainly used by logical interfaces, such as > * bonding and tunnels > + * @netmem_tx: device support netmem_tx. > * > * @name: This is the first field of the "visible" part of this structure > * (i.e. as seen by users in the "Space.c" file). It is the name > @@ -2061,6 +2062,7 @@ struct net_device { > struct_group(priv_flags_fast, > unsigned long priv_flags:32; > unsigned long lltx:1; > + unsigned long netmem_tx:1; > ); > const struct net_device_ops *netdev_ops; > const struct header_ops *header_ops; > diff --git a/include/net/netmem.h b/include/net/netmem.h > index a2148ffb203d..1fb39ad63290 100644 > --- a/include/net/netmem.h > +++ b/include/net/netmem.h > @@ -8,6 +8,7 @@ > #ifndef _NET_NETMEM_H > #define _NET_NETMEM_H > > +#include <linux/dma-mapping.h> > #include <linux/mm.h> > #include <net/net_debug.h> > > @@ -267,4 +268,23 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) > void get_netmem(netmem_ref netmem); > void put_netmem(netmem_ref netmem); > [..] > +#define netmem_dma_unmap_addr_set(NETMEM, PTR, ADDR_NAME, VAL) \ > + do { \ > + if (!netmem_is_net_iov(NETMEM)) \ > + dma_unmap_addr_set(PTR, ADDR_NAME, VAL); \ > + else \ > + dma_unmap_addr_set(PTR, ADDR_NAME, 0); \ > + } while (0) Any reason not do to static inline instaed?
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst index 15e31ece675f..e3043b033647 100644 --- a/Documentation/networking/net_cachelines/net_device.rst +++ b/Documentation/networking/net_cachelines/net_device.rst @@ -10,6 +10,7 @@ Type Name fastpath_tx_acce =================================== =========================== =================== =================== =================================================================================== unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx) unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx) +unsigned long:1 netmem_tx:1; read_mostly char name[16] struct netdev_name_node* name_node struct dev_ifalias* ifalias diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst index 5014f7cc1398..02bd7536fc0c 100644 --- a/Documentation/networking/netdev-features.rst +++ b/Documentation/networking/netdev-features.rst @@ -188,3 +188,8 @@ Redundancy) frames from one port to another in hardware. This should be set for devices which duplicate outgoing HSR (High-availability Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically frames in hardware. + +* netmem-tx + +This should be set for devices which support netmem TX. See +Documentation/networking/netmem.rst diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst index 7de21ddb5412..43054d44c407 100644 --- a/Documentation/networking/netmem.rst +++ b/Documentation/networking/netmem.rst @@ -19,8 +19,8 @@ Benefits of Netmem : * Simplified Development: Drivers interact with a consistent API, regardless of the underlying memory implementation. -Driver Requirements -=================== +Driver RX Requirements +====================== 1. The driver must support page_pool. @@ -77,3 +77,13 @@ Driver Requirements that purpose, but be mindful that some netmem types might have longer circulation times, such as when userspace holds a reference in zerocopy scenarios. + +Driver TX Requirements +====================== + +1. Driver should use netmem_dma_unmap_page_attrs() in lieu of + dma_unmap_page[_attrs](), and netmem_dma_unmap_addr_set() in lieu of + dma_unmap_addr_set(). The netmem variants will handle netmems that should + not be dma-unmapped by the driver, such as dma-buf netmems. + +2. Driver should declare support by setting `netdev->netmem_tx = true` diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index fccc03cd2164..d8cfd5d69ddf 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1753,6 +1753,7 @@ enum netdev_reg_state { * @lltx: device supports lockless Tx. Deprecated for real HW * drivers. Mainly used by logical interfaces, such as * bonding and tunnels + * @netmem_tx: device support netmem_tx. * * @name: This is the first field of the "visible" part of this structure * (i.e. as seen by users in the "Space.c" file). It is the name @@ -2061,6 +2062,7 @@ struct net_device { struct_group(priv_flags_fast, unsigned long priv_flags:32; unsigned long lltx:1; + unsigned long netmem_tx:1; ); const struct net_device_ops *netdev_ops; const struct header_ops *header_ops; diff --git a/include/net/netmem.h b/include/net/netmem.h index a2148ffb203d..1fb39ad63290 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -8,6 +8,7 @@ #ifndef _NET_NETMEM_H #define _NET_NETMEM_H +#include <linux/dma-mapping.h> #include <linux/mm.h> #include <net/net_debug.h> @@ -267,4 +268,23 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) void get_netmem(netmem_ref netmem); void put_netmem(netmem_ref netmem); +#define netmem_dma_unmap_addr_set(NETMEM, PTR, ADDR_NAME, VAL) \ + do { \ + if (!netmem_is_net_iov(NETMEM)) \ + dma_unmap_addr_set(PTR, ADDR_NAME, VAL); \ + else \ + dma_unmap_addr_set(PTR, ADDR_NAME, 0); \ + } while (0) + +static inline void netmem_dma_unmap_page_attrs(struct device *dev, + dma_addr_t addr, size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + if (!addr) + return; + + dma_unmap_page_attrs(dev, addr, size, dir, attrs); +} + #endif /* _NET_NETMEM_H */
Drivers need to make sure not to pass netmem dma-addrs to the dma-mapping API in order to support netmem TX. Add helpers and netmem_dma_*() helpers that enables special handling of netmem dma-addrs that drivers can use. Document in netmem.rst what drivers need to do to support netmem TX. Signed-off-by: Mina Almasry <almasrymina@google.com> --- v4: - New patch --- .../networking/net_cachelines/net_device.rst | 1 + Documentation/networking/netdev-features.rst | 5 +++++ Documentation/networking/netmem.rst | 14 +++++++++++-- include/linux/netdevice.h | 2 ++ include/net/netmem.h | 20 +++++++++++++++++++ 5 files changed, 40 insertions(+), 2 deletions(-)