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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 |
+--------+ +--------+
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| +----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>
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Shared Memory Communications Direct over ISM devices (SMC-D)
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*
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* SMC-D ISM device structure definitions.
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*
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* Copyright IBM Corp. 2018
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*/
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#ifndef SMCD_ISM_H
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#define SMCD_ISM_H
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#include <linux/uio.h>
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include "smc.h"
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#define SMC_EMULATED_ISM_CHID_MASK 0xFF00
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#define SMC_ISM_IDENT_MASK 0x00FFFF
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struct smcd_dev_list { /* List of SMCD devices */
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struct list_head list;
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struct mutex mutex; /* Protects list of devices */
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};
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extern struct smcd_dev_list smcd_dev_list; /* list of smcd devices */
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struct smc_ism_vlanid { /* VLAN id set on ISM device */
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struct list_head list;
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unsigned short vlanid; /* Vlan id */
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refcount_t refcnt; /* Reference count */
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};
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struct smc_ism_seid {
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u8 seid_string[24];
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u8 serial_number[4];
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u8 type[4];
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};
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struct smcd_dev;
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int smc_ism_cantalk(struct smcd_gid *peer_gid, unsigned short vlan_id,
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struct smcd_dev *dev);
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void smc_ism_set_conn(struct smc_connection *conn);
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void smc_ism_unset_conn(struct smc_connection *conn);
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int smc_ism_get_vlan(struct smcd_dev *dev, unsigned short vlan_id);
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int smc_ism_put_vlan(struct smcd_dev *dev, unsigned short vlan_id);
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int smc_ism_register_dmb(struct smc_link_group *lgr, int buf_size,
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struct smc_buf_desc *dmb_desc);
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int smc_ism_unregister_dmb(struct smcd_dev *dev, struct smc_buf_desc *dmb_desc);
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bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd);
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int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token,
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struct smc_buf_desc *dmb_desc);
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int smc_ism_detach_dmb(struct smcd_dev *dev, u64 token);
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int smc_ism_signal_shutdown(struct smc_link_group *lgr);
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void smc_ism_get_system_eid(u8 **eid);
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u16 smc_ism_get_chid(struct smcd_dev *dev);
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bool smc_ism_is_v2_capable(void);
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void smc_ism_set_v2_capable(void);
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int smc_ism_init(void);
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void smc_ism_exit(void);
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int smcd_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb);
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static inline int smc_ism_write(struct smcd_dev *smcd, u64 dmb_tok,
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unsigned int idx, bool sf, unsigned int offset,
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void *data, size_t len)
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{
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int rc;
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rc = smcd->ops->move_data(smcd, dmb_tok, idx, sf, offset, data, len);
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return rc < 0 ? rc : 0;
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}
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static inline bool __smc_ism_is_emulated(u16 chid)
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{
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/* CHIDs in range of 0xFF00 to 0xFFFF are reserved
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* for Emulated-ISM device.
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*
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* loopback-ism: 0xFFFF
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* virtio-ism: 0xFF00 ~ 0xFFFE
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*/
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return ((chid & 0xFF00) == 0xFF00);
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}
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static inline bool smc_ism_is_emulated(struct smcd_dev *smcd)
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{
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u16 chid = smcd->ops->get_chid(smcd);
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return __smc_ism_is_emulated(chid);
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}
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static inline bool smc_ism_is_loopback(struct smcd_dev *smcd)
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{
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return (smcd->ops->get_chid(smcd) == 0xFFFF);
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}
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#endif
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