6.6-stable review patch. If anyone has any objections, please let me know.
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From: Wen Gu guwen@linux.alibaba.com
[ Upstream commit 4398888268582cb51b69c6ee94f551bb8d37d12f ]
In some scenarios using Emulated-ISM device, sndbuf can share the same physical memory region with peer DMB to avoid data copy from one side to the other. In such case the sndbuf is only a descriptor that describes the shared memory and does not actually occupy memory, it's more like a ghost buffer.
+----------+ +----------+ | socket A | | socket B | +----------+ +----------+ | | +--------+ +--------+ | sndbuf | | DMB | | desc | | desc | +--------+ +--------+ | | | +----v-----+ +--------------------------> memory | +----------+
So here introduces three new SMC-D device operations to check if this feature is supported by device, and to {attach|detach} ghost sndbuf to peer DMB. For now only loopback-ism supports this.
Signed-off-by: Wen Gu guwen@linux.alibaba.com Reviewed-by: Wenjia Zhang wenjia@linux.ibm.com Reviewed-and-tested-by: Jan Karcher jaka@linux.ibm.com Signed-off-by: Paolo Abeni pabeni@redhat.com Stable-dep-of: 0541db8ee32c ("net/smc: initialize close_work early to avoid warning") Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/smc.h | 3 +++ net/smc/smc_ism.c | 40 ++++++++++++++++++++++++++++++++++++++++ net/smc/smc_ism.h | 4 ++++ 3 files changed, 47 insertions(+)
diff --git a/include/net/smc.h b/include/net/smc.h index 9dfe57f3e4f0b..6fef76087b9ed 100644 --- a/include/net/smc.h +++ b/include/net/smc.h @@ -79,6 +79,9 @@ struct smcd_ops { int (*reset_vlan_required)(struct smcd_dev *dev); int (*signal_event)(struct smcd_dev *dev, struct smcd_gid *rgid, u32 trigger_irq, u32 event_code, u64 info); + int (*support_dmb_nocopy)(struct smcd_dev *dev); + int (*attach_dmb)(struct smcd_dev *dev, struct smcd_dmb *dmb); + int (*detach_dmb)(struct smcd_dev *dev, u64 token); };
struct smcd_dev { diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c index 3623df320de55..61ffc72014013 100644 --- a/net/smc/smc_ism.c +++ b/net/smc/smc_ism.c @@ -228,6 +228,46 @@ int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len, #endif }
+bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd) +{ + /* for now only loopback-ism supports + * merging sndbuf with peer DMB to avoid + * data copies between them. + */ + return (smcd->ops->support_dmb_nocopy && + smcd->ops->support_dmb_nocopy(smcd)); +} + +int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token, + struct smc_buf_desc *dmb_desc) +{ + struct smcd_dmb dmb; + int rc = 0; + + if (!dev->ops->attach_dmb) + return -EINVAL; + + memset(&dmb, 0, sizeof(dmb)); + dmb.dmb_tok = token; + rc = dev->ops->attach_dmb(dev, &dmb); + if (!rc) { + dmb_desc->sba_idx = dmb.sba_idx; + dmb_desc->token = dmb.dmb_tok; + dmb_desc->cpu_addr = dmb.cpu_addr; + dmb_desc->dma_addr = dmb.dma_addr; + dmb_desc->len = dmb.dmb_len; + } + return rc; +} + +int smc_ism_detach_dmb(struct smcd_dev *dev, u64 token) +{ + if (!dev->ops->detach_dmb) + return -EINVAL; + + return dev->ops->detach_dmb(dev, token); +} + static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd, struct sk_buff *skb, struct netlink_callback *cb) diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h index 0e5e563099ec3..8312c3586d2b3 100644 --- a/net/smc/smc_ism.h +++ b/net/smc/smc_ism.h @@ -41,6 +41,10 @@ int smc_ism_put_vlan(struct smcd_dev *dev, unsigned short vlan_id); int smc_ism_register_dmb(struct smc_link_group *lgr, int buf_size, struct smc_buf_desc *dmb_desc); int smc_ism_unregister_dmb(struct smcd_dev *dev, struct smc_buf_desc *dmb_desc); +bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd); +int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token, + struct smc_buf_desc *dmb_desc); +int smc_ism_detach_dmb(struct smcd_dev *dev, u64 token); int smc_ism_signal_shutdown(struct smc_link_group *lgr); void smc_ism_get_system_eid(u8 **eid); u16 smc_ism_get_chid(struct smcd_dev *dev);