RDMA/ucma: Support write an event into a CM

Enable user-space to inject an event into a CM through it's event
channel. Two new events are added and supported: RDMA_CM_EVENT_USER and
RDMA_CM_EVENT_INTERNAL. With these 2 events a new event parameter "arg"
is supported, which is passed from sender to receiver transparently.

With this feature an application is able to write an event into a CM
channel with a new user-space rdmacm API. For example thread T1 could
write an event with the API:
    rdma_write_cm_event(cm_id, RDMA_CM_EVENT_USER, status, arg);
and thread T2 could receive the event with rdma_get_cm_event().

Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Reviewed-by: Vlad Dumitrescu <vdumitrescu@nvidia.com>
Link: https://patch.msgid.link/fdf49d0b17a45933c5d8c1d90605c9447d9a3c73.1751279794.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 3b9ca6d7a21b83c7cf1c72cf7d145f00e1cbcb44..f86ece701db6e081a06f76fa5026f690449624ec 100644 (file)
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1745,6 +1745,55 @@ err_unlock:
        return ret;
 }
 
+static ssize_t ucma_write_cm_event(struct ucma_file *file,
+                                  const char __user *inbuf, int in_len,
+                                  int out_len)
+{
+       struct rdma_ucm_write_cm_event cmd;
+       struct rdma_cm_event event = {};
+       struct ucma_event *uevent;
+       struct ucma_context *ctx;
+       int ret = 0;
+
+       if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+               return -EFAULT;
+
+       if ((cmd.event != RDMA_CM_EVENT_USER) &&
+           (cmd.event != RDMA_CM_EVENT_INTERNAL))
+               return -EINVAL;
+
+       ctx = ucma_get_ctx(file, cmd.id);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       event.event = cmd.event;
+       event.status = cmd.status;
+       event.param.arg = cmd.param.arg;
+
+       uevent = kzalloc(sizeof(*uevent), GFP_KERNEL);
+       if (!uevent) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       uevent->ctx = ctx;
+       uevent->resp.uid = ctx->uid;
+       uevent->resp.id = ctx->id;
+       uevent->resp.event = event.event;
+       uevent->resp.status = event.status;
+       memcpy(uevent->resp.param.arg32, &event.param.arg,
+              sizeof(event.param.arg));
+
+       mutex_lock(&ctx->file->mut);
+       list_add_tail(&uevent->list, &ctx->file->event_list);
+       mutex_unlock(&ctx->file->mut);
+       wake_up_interruptible(&ctx->file->poll_wait);
+
+out:
+       ucma_put_ctx(ctx);
+       return ret;
+}
+
 static ssize_t (*ucma_cmd_table[])(struct ucma_file *file,
                                   const char __user *inbuf,
                                   int in_len, int out_len) = {
@@ -1771,7 +1820,8 @@ static ssize_t (*ucma_cmd_table[])(struct ucma_file *file,
        [RDMA_USER_CM_CMD_BIND]          = ucma_bind,
        [RDMA_USER_CM_CMD_RESOLVE_ADDR]  = ucma_resolve_addr,
        [RDMA_USER_CM_CMD_JOIN_MCAST]    = ucma_join_multicast,
-       [RDMA_USER_CM_CMD_RESOLVE_IB_SERVICE] = ucma_resolve_ib_service
+       [RDMA_USER_CM_CMD_RESOLVE_IB_SERVICE] = ucma_resolve_ib_service,
+       [RDMA_USER_CM_CMD_WRITE_CM_EVENT] = ucma_write_cm_event,
 };
 
 static ssize_t ucma_write(struct file *filp, const char __user *buf,

diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h
index 72d1568e4cfb4234751f710d62139740c84835a1..9bd930a83e6e39d6b23709369f513f8c93a7a09f 100644 (file)
--- a/include/rdma/rdma_cm.h
+++ b/include/rdma/rdma_cm.h
@@ -35,7 +35,9 @@ enum rdma_cm_event_type {
        RDMA_CM_EVENT_ADDR_CHANGE,
        RDMA_CM_EVENT_TIMEWAIT_EXIT,
        RDMA_CM_EVENT_ADDRINFO_RESOLVED,
-       RDMA_CM_EVENT_ADDRINFO_ERROR
+       RDMA_CM_EVENT_ADDRINFO_ERROR,
+       RDMA_CM_EVENT_USER,
+       RDMA_CM_EVENT_INTERNAL,
 };
 
 const char *__attribute_const__ rdma_event_msg(enum rdma_cm_event_type event);
@@ -98,6 +100,7 @@ struct rdma_cm_event {
        union {
                struct rdma_conn_param  conn;
                struct rdma_ud_param    ud;
+               u64                     arg;
        } param;
        struct rdma_ucm_ece ece;
 };

diff --git a/include/uapi/rdma/rdma_user_cm.h b/include/uapi/rdma/rdma_user_cm.h
index 00501da0567e33319dd7b5d96fc51c0be7096117..5ded174687ee045ee1144ac9b9ce00a55377449b 100644 (file)
--- a/include/uapi/rdma/rdma_user_cm.h
+++ b/include/uapi/rdma/rdma_user_cm.h
@@ -68,7 +68,8 @@ enum {
        RDMA_USER_CM_CMD_BIND,
        RDMA_USER_CM_CMD_RESOLVE_ADDR,
        RDMA_USER_CM_CMD_JOIN_MCAST,
-       RDMA_USER_CM_CMD_RESOLVE_IB_SERVICE
+       RDMA_USER_CM_CMD_RESOLVE_IB_SERVICE,
+       RDMA_USER_CM_CMD_WRITE_CM_EVENT,
 };
 
 /* See IBTA Annex A11, servies ID bytes 4 & 5 */
@@ -304,6 +305,7 @@ struct rdma_ucm_event_resp {
        union {
                struct rdma_ucm_conn_param conn;
                struct rdma_ucm_ud_param   ud;
+               __u32 arg32[2];
        } param;
        __u32 reserved;
        struct rdma_ucm_ece ece;
@@ -362,4 +364,16 @@ struct rdma_ucm_resolve_ib_service {
        __u32 id;
        struct rdma_ucm_ib_service ibs;
 };
+
+struct rdma_ucm_write_cm_event {
+       __u32 id;
+       __u32 reserved;
+       __u32 event;
+       __u32 status;
+       union {
+               struct rdma_ucm_conn_param conn;
+               struct rdma_ucm_ud_param ud;
+               __u64 arg;
+       } param;
+};
 #endif /* RDMA_USER_CM_H */