On 21.09.23 15:19, Wen Gu wrote:
> This patch introduces a kind of loopback device for SMC-D. The device
> is created when SMC module is loaded and destroyed when the SMC module
> is unloaded. The loopback device is a kernel device used only by the
> SMC module and is not restricted by net namespace, so it can be used
> for local inter-process or inter-container communication.
>
> Signed-off-by: Wen Gu <[email protected]>
> ---
> net/smc/Makefile | 2 +-
> net/smc/af_smc.c | 12 +++-
> net/smc/smc_loopback.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++
> net/smc/smc_loopback.h | 31 ++++++++++
> 4 files changed, 200 insertions(+), 2 deletions(-)
> create mode 100644 net/smc/smc_loopback.c
> create mode 100644 net/smc/smc_loopback.h
>
> diff --git a/net/smc/Makefile b/net/smc/Makefile
> index 875efcd..a8c3711 100644
> --- a/net/smc/Makefile
> +++ b/net/smc/Makefile
> @@ -4,5 +4,5 @@ obj-$(CONFIG_SMC) += smc.o
> obj-$(CONFIG_SMC_DIAG) += smc_diag.o
> smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o smc_llc.o
> smc-y += smc_cdc.o smc_tx.o smc_rx.o smc_close.o smc_ism.o smc_netlink.o smc_stats.o
> -smc-y += smc_tracepoint.o
> +smc-y += smc_tracepoint.o smc_loopback.o
> smc-$(CONFIG_SYSCTL) += smc_sysctl.o
> diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
> index 7eab600..bc4300e 100644
> --- a/net/smc/af_smc.c
> +++ b/net/smc/af_smc.c
> @@ -53,6 +53,7 @@
> #include "smc_stats.h"
> #include "smc_tracepoint.h"
> #include "smc_sysctl.h"
> +#include "smc_loopback.h"
>
> static DEFINE_MUTEX(smc_server_lgr_pending); /* serialize link group
> * creation on server
> @@ -3552,15 +3553,23 @@ static int __init smc_init(void)
> goto out_sock;
> }
>
> + rc = smc_loopback_init();
> + if (rc) {
> + pr_err("%s: smc_loopback_init fails with %d\n", __func__, rc);
> + goto out_ib;
> + }
> +
> rc = tcp_register_ulp(&smc_ulp_ops);
> if (rc) {
> pr_err("%s: tcp_ulp_register fails with %d\n", __func__, rc);
> - goto out_ib;
> + goto out_lo;
> }
>
> static_branch_enable(&tcp_have_smc);
> return 0;
>
> +out_lo:
> + smc_loopback_exit();
> out_ib:
> smc_ib_unregister_client();
> out_sock:
> @@ -3598,6 +3607,7 @@ static void __exit smc_exit(void)
> tcp_unregister_ulp(&smc_ulp_ops);
> sock_unregister(PF_SMC);
> smc_core_exit();
> + smc_loopback_exit();
> smc_ib_unregister_client();
> smc_ism_exit();
> destroy_workqueue(smc_close_wq);
> diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
> new file mode 100644
> index 0000000..7d88856
> --- /dev/null
> +++ b/net/smc/smc_loopback.c
> @@ -0,0 +1,157 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Shared Memory Communications Direct over loopback device.
> + *
> + * Provide a SMC-D loopback dummy device.
> + *
> + * Copyright (c) 2022, Alibaba Inc.
> + *
> + * Author: Wen Gu <[email protected]>
> + * Tony Lu <[email protected]>
> + *
> + */
> +
> +#include <linux/device.h>
> +#include <linux/types.h>
> +#include <net/smc.h>
> +
> +#include "smc_ism.h"
> +#include "smc_loopback.h"
> +
> +static const char smc_lo_dev_name[] = "smc_lo";
> +static struct smc_lo_dev *lo_dev;
> +
> +static const struct smcd_ops lo_ops = {
> + .query_remote_gid = NULL,
> + .register_dmb = NULL,
> + .unregister_dmb = NULL,
> + .add_vlan_id = NULL,
> + .del_vlan_id = NULL,
> + .set_vlan_required = NULL,
> + .reset_vlan_required = NULL,
> + .signal_event = NULL,
> + .move_data = NULL,
> + .supports_v2 = NULL,
> + .get_system_eid = NULL,
> + .get_local_gid = NULL,
> + .get_chid = NULL,
> + .get_dev = NULL,
> +};
> +
> +static struct smcd_dev *smcd_lo_alloc_dev(const struct smcd_ops *ops,
> + int max_dmbs)
> +{
> + struct smcd_dev *smcd;
> +
> + smcd = kzalloc(sizeof(*smcd), GFP_KERNEL);
> + if (!smcd)
> + return NULL;
> +
> + smcd->conn = kcalloc(max_dmbs, sizeof(struct smc_connection *),
> + GFP_KERNEL);
> + if (!smcd->conn)
> + goto out_smcd;
> +
> + smcd->ops = ops;
> +
> + spin_lock_init(&smcd->lock);
> + spin_lock_init(&smcd->lgr_lock);
> + INIT_LIST_HEAD(&smcd->vlan);
> + INIT_LIST_HEAD(&smcd->lgr_list);
> + init_waitqueue_head(&smcd->lgrs_deleted);
> + return smcd;
> +
> +out_smcd:
> + kfree(smcd);
> + return NULL;
> +}
> +
> +static int smcd_lo_register_dev(struct smc_lo_dev *ldev)
> +{
> + struct smcd_dev *smcd;
> +
> + smcd = smcd_lo_alloc_dev(&lo_ops, SMC_LODEV_MAX_DMBS);
> + if (!smcd)
> + return -ENOMEM;
> +
> + ldev->smcd = smcd;
> + smcd->priv = ldev;
> +
> + /* TODO:
> + * register smc_lo to smcd_dev list.
> + */
> + return 0;
> +}
> +
> +static void smcd_lo_unregister_dev(struct smc_lo_dev *ldev)
> +{
> + /* TODO:
> + * unregister smc_lo from smcd_dev list.
> + */
> +}
> +
> +static void smc_lo_dev_release(struct device *dev)
> +{
> + struct smc_lo_dev *ldev =
> + container_of(dev, struct smc_lo_dev, dev);
> + struct smcd_dev *smcd = ldev->smcd;
> +
> + kfree(smcd->conn);
> + kfree(smcd);
> + kfree(ldev);
> +}
> +
> +static int smc_lo_dev_init(struct smc_lo_dev *ldev)
> +{
> + return smcd_lo_register_dev(ldev);
> +}
> +
> +static int smc_lo_dev_probe(void)
> +{
> + struct smc_lo_dev *ldev;
> + int ret;
> +
> + ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
> + if (!ldev)
> + return -ENOMEM;
> +
> + ldev->dev.parent = NULL;
> + ldev->dev.release = smc_lo_dev_release;
> + device_initialize(&ldev->dev);
> + dev_set_name(&ldev->dev, smc_lo_dev_name);
> +
> + ret = smc_lo_dev_init(ldev);
> + if (ret)
> + goto free_dev;
> +
> + lo_dev = ldev; /* global loopback device */
> + return 0;
> +
> +free_dev:
> + kfree(ldev);
> + return ret;
> +}
> +
> +static void smc_lo_dev_exit(struct smc_lo_dev *ldev)
> +{
> + smcd_lo_unregister_dev(ldev);
> +}
> +
> +static void smc_lo_dev_remove(void)
> +{
> + if (!lo_dev)
> + return;
> +
> + smc_lo_dev_exit(lo_dev);
> + put_device(&lo_dev->dev); /* device_initialize in smc_lo_dev_probe */
> +}
> +
> +int smc_loopback_init(void)
> +{
> + return smc_lo_dev_probe();
> +}
> +
> +void smc_loopback_exit(void)
> +{
> + smc_lo_dev_remove();
> +}
> diff --git a/net/smc/smc_loopback.h b/net/smc/smc_loopback.h
> new file mode 100644
> index 0000000..0f7583c
> --- /dev/null
> +++ b/net/smc/smc_loopback.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Shared Memory Communications Direct over loopback device.
> + *
> + * Provide a SMC-D loopback dummy device.
> + *
> + * Copyright (c) 2022, Alibaba Inc.
> + *
> + * Author: Wen Gu <[email protected]>
> + * Tony Lu <[email protected]>
> + *
> + */
> +
> +#ifndef _SMC_LOOPBACK_H
> +#define _SMC_LOOPBACK_H
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <net/smc.h>
> +
> +#define SMC_LODEV_MAX_DMBS 5000
> +
> +struct smc_lo_dev {
> + struct smcd_dev *smcd;
> + struct device dev;
> +};
> +
I'm just wondering why don't use pointer for dev?
> +int smc_loopback_init(void);
> +void smc_loopback_exit(void);
> +
> +#endif /* _SMC_LOOPBACK_H */
On 2023/9/22 07:32, Wenjia Zhang wrote:
>
>
<..>
>> +
>> +#ifndef _SMC_LOOPBACK_H
>> +#define _SMC_LOOPBACK_H
>> +
>> +#include <linux/device.h>
>> +#include <linux/err.h>
>> +#include <net/smc.h>
>> +
>> +#define SMC_LODEV_MAX_DMBS 5000
>> +
>> +struct smc_lo_dev {
>> + struct smcd_dev *smcd;
>> + struct device dev;
>> +};
>> +
> I'm just wondering why don't use pointer for dev?
>
The 'struct device' is a generic structure embeded, used to associate a Linux device
with a specific device. So I think variable for dev here is OK. See also struct ism_dev.
Thanks.
>> +int smc_loopback_init(void);
>> +void smc_loopback_exit(void);
>> +
>> +#endif /* _SMC_LOOPBACK_H */