linux/net/smc/smc_ism.h
Wen Gu 4398888268 net/smc: add operations to merge sndbuf with peer DMB
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>
2024-04-30 13:24:48 +02:00

98 lines
2.6 KiB
C

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