From: Yishai Hadas <yish...@mellanox.com>

Implement DEVX dispatching event by looking up for the applicable
subscriptions for the reported event and using their target fd to
signal/set the event.

Signed-off-by: Yishai Hadas <yish...@mellanox.com>
Signed-off-by: Leon Romanovsky <leo...@mellanox.com>
---
 drivers/infiniband/hw/mlx5/devx.c         | 362 +++++++++++++++++++++-
 include/uapi/rdma/mlx5_user_ioctl_verbs.h |   5 +
 2 files changed, 357 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/devx.c 
b/drivers/infiniband/hw/mlx5/devx.c
index 304b13e7a265..49fdce95d6d9 100644
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -34,6 +34,11 @@ struct devx_async_data {
        struct mlx5_ib_uapi_devx_async_cmd_hdr hdr;
 };
 
+struct devx_async_event_data {
+       struct list_head list; /* headed in ev_queue->event_list */
+       struct mlx5_ib_uapi_devx_async_event_hdr hdr;
+};
+
 /* first level XA value data structure */
 struct devx_event {
        struct xarray object_ids; /* second XA level, Key = object id */
@@ -54,7 +59,9 @@ struct devx_event_subscription {
                                   * devx_obj_event->obj_sub_list
                                   */
        struct list_head obj_list; /* headed in devx_object */
+       struct list_head event_list; /* headed in ev_queue->event_list */
 
+       u8  is_cleaned:1;
        u32 xa_key_level1;
        u32 xa_key_level2;
        struct rcu_head rcu;
@@ -71,6 +78,7 @@ struct devx_async_event_queue {
        struct list_head        event_list;
        atomic_t                bytes_in_use;
        u8                      is_destroyed:1;
+       u8                      is_overflow_err:1;
        u32                     flags;
 };
 
@@ -294,6 +302,46 @@ static u16 get_dec_obj_type(struct devx_obj *obj, u16 
event_num)
        }
 }
 
+/* Any future affiliated event should have a fixed header to get the obj
+ * type and id including events on legacy objects.
+ */
+static u32 get_affiliated_event_obj_id(struct mlx5_eqe *eqe)
+{
+       u32 obj_id = MLX5_GET(affiliated_event_header, eqe, obj_id);
+
+       return obj_id;
+}
+
+static u16 get_affiliated_event_obj_type(struct mlx5_eqe *eqe)
+{
+       u16 obj_type = MLX5_GET(affiliated_event_header, eqe, obj_type);
+
+       return obj_type;
+}
+
+static u16 get_event_obj_type(unsigned long event_type, struct mlx5_eqe *eqe)
+{
+       switch (event_type) {
+       case MLX5_EVENT_TYPE_WQ_CATAS_ERROR:
+       case MLX5_EVENT_TYPE_WQ_ACCESS_ERROR:
+       case MLX5_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
+       case MLX5_EVENT_TYPE_SRQ_LAST_WQE:
+       case MLX5_EVENT_TYPE_PATH_MIG:
+       case MLX5_EVENT_TYPE_PATH_MIG_FAILED:
+       case MLX5_EVENT_TYPE_COMM_EST:
+       case MLX5_EVENT_TYPE_SQ_DRAINED:
+       case MLX5_EVENT_TYPE_SRQ_RQ_LIMIT:
+       case MLX5_EVENT_TYPE_SRQ_CATAS_ERROR:
+               return eqe->data.qp_srq.type;
+       case MLX5_EVENT_TYPE_CQ_ERROR:
+               return 0;
+       case MLX5_EVENT_TYPE_DCT_DRAINED:
+               return MLX5_EVENT_QUEUE_TYPE_DCT;
+       default:
+               return get_affiliated_event_obj_type(eqe);
+       }
+}
+
 static u32 get_dec_obj_id(u64 obj_id)
 {
        return (obj_id & 0xffffffff);
@@ -1276,9 +1324,13 @@ static void devx_cleanup_mkey(struct devx_obj *obj)
 }
 
 static void devx_cleanup_subscription(struct mlx5_ib_dev *dev,
-                                     struct devx_event_subscription *sub)
+                                     struct devx_event_subscription *sub,
+                                     bool file_close)
 {
-       list_del_rcu(&sub->file_list);
+       if (sub->is_cleaned)
+               goto end;
+
+       sub->is_cleaned = 1;
        list_del_rcu(&sub->xa_list);
 
        if (sub->is_obj_related) {
@@ -1303,10 +1355,15 @@ static void devx_cleanup_subscription(struct 
mlx5_ib_dev *dev,
                }
        }
 
-       if (sub->eventfd)
-               eventfd_ctx_put(sub->eventfd);
+end:
+       if (file_close) {
+               if (sub->eventfd)
+                       eventfd_ctx_put(sub->eventfd);
 
-       kfree_rcu(sub, rcu);
+               list_del_rcu(&sub->file_list);
+               /* subscription may not be used by the read API any more */
+               kfree_rcu(sub, rcu);
+       }
 }
 
 static int devx_obj_cleanup(struct ib_uobject *uobject,
@@ -1338,7 +1395,7 @@ static int devx_obj_cleanup(struct ib_uobject *uobject,
 
        mutex_lock(&devx_event_table->event_xa_lock);
        list_for_each_entry_safe(sub_entry, tmp, &obj->event_sub, obj_list)
-               devx_cleanup_subscription(dev, sub_entry);
+               devx_cleanup_subscription(dev, sub_entry, false);
        mutex_unlock(&devx_event_table->event_xa_lock);
 
        if (obj->flags & DEVX_OBJ_FLAGS_INDIRECT_MKEY) {
@@ -1588,6 +1645,7 @@ static int 
UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_ASYNC_EVENT_FD_ALLOC)(
        devx_init_event_queue(&ev_file->ev_queue, flags);
        INIT_LIST_HEAD(&ev_file->subscribed_events_list);
        ev_file->dev = dev;
+       get_device(&dev->ib_dev.dev);
        return 0;
 }
 
@@ -1981,6 +2039,7 @@ static int 
UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_SUBSCRIBE_EVENT)(
                event_sub_arr[i]->xa_key_level1 = key_level1;
                event_sub_arr[i]->xa_key_level2 = obj_id;
                event_sub_arr[i]->is_obj_related = obj ? true : false;
+               INIT_LIST_HEAD(&event_sub_arr[i]->event_list);
        }
 
        /* Once all the allocations and the reservations for level 2
@@ -2191,10 +2250,174 @@ static int devx_umem_cleanup(struct ib_uobject 
*uobject,
        return 0;
 }
 
+static bool is_unaffiliated_event(struct mlx5_core_dev *dev,
+                                 unsigned long event_type)
+{
+       __be64 *unaff_events;
+       int mask_entry;
+       int mask_bit;
+
+       if (!MLX5_CAP_GEN(dev, event_cap))
+               return is_legacy_unaffiliated_event_num(event_type);
+
+       unaff_events = MLX5_CAP_DEV_EVENT(dev,
+                                         user_unaffiliated_events);
+       WARN_ON(event_type > MAX_SUPP_EVENT_NUM);
+
+       mask_entry = event_type / 64;
+       mask_bit = event_type % 64;
+
+       if (!(be64_to_cpu(unaff_events[mask_entry]) & (1ull << mask_bit)))
+               return false;
+
+       return true;
+}
+
+static u32 devx_get_obj_id_from_event(unsigned long event_type, void *data)
+{
+       struct mlx5_eqe *eqe = data;
+       u32 obj_id = 0;
+
+       switch (event_type) {
+       case MLX5_EVENT_TYPE_SRQ_CATAS_ERROR:
+       case MLX5_EVENT_TYPE_SRQ_RQ_LIMIT:
+       case MLX5_EVENT_TYPE_PATH_MIG:
+       case MLX5_EVENT_TYPE_COMM_EST:
+       case MLX5_EVENT_TYPE_SQ_DRAINED:
+       case MLX5_EVENT_TYPE_SRQ_LAST_WQE:
+       case MLX5_EVENT_TYPE_WQ_CATAS_ERROR:
+       case MLX5_EVENT_TYPE_PATH_MIG_FAILED:
+       case MLX5_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
+       case MLX5_EVENT_TYPE_WQ_ACCESS_ERROR:
+               obj_id = be32_to_cpu(eqe->data.qp_srq.qp_srq_n) & 0xffffff;
+               break;
+       case MLX5_EVENT_TYPE_DCT_DRAINED:
+               obj_id = be32_to_cpu(eqe->data.dct.dctn) & 0xffffff;
+               break;
+       case MLX5_EVENT_TYPE_CQ_ERROR:
+               obj_id = be32_to_cpu(eqe->data.cq_err.cqn) & 0xffffff;
+               break;
+       default:
+               obj_id = get_affiliated_event_obj_id(data);
+               break;
+       }
+
+       return obj_id;
+}
+
+static int deliver_event(struct devx_event_subscription *event_sub,
+                        const void *data)
+{
+       struct ib_uobject *fd_uobj = event_sub->fd_uobj;
+       struct devx_async_event_file *ev_file;
+       struct devx_async_event_queue *ev_queue;
+       struct devx_async_event_data *event_data;
+       unsigned long flags;
+       bool omit_data;
+
+       ev_file = container_of(fd_uobj, struct devx_async_event_file,
+                              uobj);
+       ev_queue = &ev_file->ev_queue;
+       omit_data = ev_queue->flags &
+               MLX5_IB_UAPI_DEVX_CREATE_EVENT_CHANNEL_FLAGS_OMIT_EV_DATA;
+
+       if (omit_data) {
+               spin_lock_irqsave(&ev_queue->lock, flags);
+               if (!list_empty(&event_sub->event_list)) {
+                       spin_unlock_irqrestore(&ev_queue->lock, flags);
+                       return 0;
+               }
+
+               list_add_tail(&event_sub->event_list, &ev_queue->event_list);
+               spin_unlock_irqrestore(&ev_queue->lock, flags);
+               wake_up_interruptible(&ev_queue->poll_wait);
+               return 0;
+       }
+
+       event_data = kzalloc(sizeof(*event_data) +
+                            (omit_data ? 0 : sizeof(struct mlx5_eqe)),
+                            GFP_ATOMIC);
+       if (!event_data) {
+               spin_lock_irqsave(&ev_queue->lock, flags);
+               ev_queue->is_overflow_err = 1;
+               spin_unlock_irqrestore(&ev_queue->lock, flags);
+               return -ENOMEM;
+       }
+
+       event_data->hdr.cookie = event_sub->cookie;
+       memcpy(event_data->hdr.out_data, data, sizeof(struct mlx5_eqe));
+
+       spin_lock_irqsave(&ev_queue->lock, flags);
+       list_add_tail(&event_data->list, &ev_queue->event_list);
+       spin_unlock_irqrestore(&ev_queue->lock, flags);
+       wake_up_interruptible(&ev_queue->poll_wait);
+
+       return 0;
+}
+
+static void dispatch_event_fd(struct list_head *fd_list,
+                             const void *data)
+{
+       struct devx_event_subscription *item;
+
+       list_for_each_entry_rcu(item, fd_list, xa_list) {
+               if (!get_file_rcu((struct file *)item->object))
+                       continue;
+
+               if (item->eventfd) {
+                       eventfd_signal(item->eventfd, 1);
+                       fput(item->object);
+                       continue;
+               }
+
+               deliver_event(item, data);
+               fput(item->object);
+       }
+}
+
 static int devx_event_notifier(struct notifier_block *nb,
                               unsigned long event_type, void *data)
 {
-       return NOTIFY_DONE;
+       struct mlx5_devx_event_table *table;
+       struct mlx5_ib_dev *dev;
+       struct devx_event *event;
+       struct devx_obj_event *obj_event;
+       u16 obj_type = 0;
+       bool is_unaffiliated;
+       u32 obj_id;
+
+       /* Explicit filtering to kernel events which may occur frequently */
+       if (event_type == MLX5_EVENT_TYPE_CMD ||
+           event_type == MLX5_EVENT_TYPE_PAGE_REQUEST)
+               return NOTIFY_OK;
+
+       table = container_of(nb, struct mlx5_devx_event_table, devx_nb.nb);
+       dev = container_of(table, struct mlx5_ib_dev, devx_event_table);
+       is_unaffiliated = is_unaffiliated_event(dev->mdev, event_type);
+
+       if (!is_unaffiliated)
+               obj_type = get_event_obj_type(event_type, data);
+       event = xa_load(&table->event_xa, event_type | (obj_type << 16));
+       if (!event)
+               return NOTIFY_DONE;
+
+       if (is_unaffiliated) {
+               dispatch_event_fd(&event->unaffiliated_list, data);
+               return NOTIFY_OK;
+       }
+
+       obj_id = devx_get_obj_id_from_event(event_type, data);
+       rcu_read_lock();
+       obj_event = xa_load(&event->object_ids, obj_id);
+       if (!obj_event) {
+               rcu_read_unlock();
+               return NOTIFY_DONE;
+       }
+
+       dispatch_event_fd(&obj_event->obj_sub_list, data);
+
+       rcu_read_unlock();
+       return NOTIFY_OK;
 }
 
 void mlx5_ib_devx_init_event_table(struct mlx5_ib_dev *dev)
@@ -2221,7 +2444,7 @@ void mlx5_ib_devx_cleanup_event_table(struct mlx5_ib_dev 
*dev)
                event = entry;
                list_for_each_entry_safe(sub, tmp, &event->unaffiliated_list,
                                         xa_list)
-                       devx_cleanup_subscription(dev, sub);
+                       devx_cleanup_subscription(dev, sub, false);
                kfree(entry);
        }
        mutex_unlock(&dev->devx_event_table.event_xa_lock);
@@ -2329,18 +2552,126 @@ static const struct file_operations 
devx_async_cmd_event_fops = {
 static ssize_t devx_async_event_read(struct file *filp, char __user *buf,
                                     size_t count, loff_t *pos)
 {
-       return -EINVAL;
+       struct devx_async_event_file *ev_file = filp->private_data;
+       struct devx_async_event_queue *ev_queue = &ev_file->ev_queue;
+       struct devx_event_subscription *event_sub;
+       struct devx_async_event_data *uninitialized_var(event);
+       int ret = 0;
+       size_t eventsz;
+       bool omit_data;
+       void *event_data;
+
+       omit_data = ev_queue->flags &
+               MLX5_IB_UAPI_DEVX_CREATE_EVENT_CHANNEL_FLAGS_OMIT_EV_DATA;
+
+       spin_lock_irq(&ev_queue->lock);
+
+       if (ev_queue->is_overflow_err) {
+               ev_queue->is_overflow_err = 0;
+               spin_unlock_irq(&ev_queue->lock);
+               return -EOVERFLOW;
+       }
+
+       while (list_empty(&ev_queue->event_list)) {
+               spin_unlock_irq(&ev_queue->lock);
+
+               if (filp->f_flags & O_NONBLOCK)
+                       return -EAGAIN;
+
+               if (wait_event_interruptible(ev_queue->poll_wait,
+                           (!list_empty(&ev_queue->event_list) ||
+                            ev_queue->is_destroyed))) {
+                       return -ERESTARTSYS;
+               }
+
+               if (list_empty(&ev_queue->event_list) &&
+                   ev_queue->is_destroyed)
+                       return -EIO;
+
+               spin_lock_irq(&ev_queue->lock);
+       }
+
+       if (omit_data) {
+               event_sub = list_first_entry(&ev_queue->event_list,
+                                       struct devx_event_subscription,
+                                       event_list);
+               eventsz = sizeof(event_sub->cookie);
+               event_data = &event_sub->cookie;
+       } else {
+               event = list_first_entry(&ev_queue->event_list,
+                                     struct devx_async_event_data, list);
+               eventsz = sizeof(struct mlx5_eqe) +
+                       sizeof(struct mlx5_ib_uapi_devx_async_event_hdr);
+               event_data = &event->hdr;
+       }
+
+       if (eventsz > count) {
+               spin_unlock_irq(&ev_queue->lock);
+               return -ENOSPC;
+       }
+
+       if (omit_data)
+               list_del_init(&event_sub->event_list);
+       else
+               list_del(&event->list);
+
+       spin_unlock_irq(&ev_queue->lock);
+
+       if (copy_to_user(buf, event_data, eventsz))
+               ret = -EFAULT;
+       else
+               ret = eventsz;
+
+       if (!omit_data)
+               kfree(event);
+       return ret;
 }
 
 static __poll_t devx_async_event_poll(struct file *filp,
                                      struct poll_table_struct *wait)
 {
-       return 0;
+       struct devx_async_event_file *ev_file = filp->private_data;
+       struct devx_async_event_queue *ev_queue = &ev_file->ev_queue;
+       __poll_t pollflags = 0;
+
+       poll_wait(filp, &ev_queue->poll_wait, wait);
+
+       spin_lock_irq(&ev_queue->lock);
+       if (ev_queue->is_destroyed)
+               pollflags = EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+       else if (!list_empty(&ev_queue->event_list))
+               pollflags = EPOLLIN | EPOLLRDNORM;
+       spin_unlock_irq(&ev_queue->lock);
+
+       return pollflags;
 }
 
 static int devx_async_event_close(struct inode *inode, struct file *filp)
 {
+       struct ib_uobject *uobj = filp->private_data;
+       struct devx_async_event_file *ev_file =
+               container_of(uobj, struct devx_async_event_file, uobj);
+       struct devx_event_subscription *event_sub, *event_sub_tmp;
+       struct devx_async_event_data *entry, *tmp;
+
+       mutex_lock(&ev_file->dev->devx_event_table.event_xa_lock);
+       /* delete the subscriptions which are related to this FD */
+       list_for_each_entry_safe(event_sub, event_sub_tmp,
+                                &ev_file->subscribed_events_list, file_list)
+               devx_cleanup_subscription(ev_file->dev, event_sub, true);
+       mutex_unlock(&ev_file->dev->devx_event_table.event_xa_lock);
+
+       /* free the pending events allocation */
+       if (!(ev_file->ev_queue.flags &
+           MLX5_IB_UAPI_DEVX_CREATE_EVENT_CHANNEL_FLAGS_OMIT_EV_DATA)) {
+               spin_lock_irq(&ev_file->ev_queue.lock);
+               list_for_each_entry_safe(entry, tmp,
+                                        &ev_file->ev_queue.event_list, list)
+                       kfree(entry); /* read can't come any nore */
+               spin_unlock_irq(&ev_file->ev_queue.lock);
+       }
        uverbs_close_fd(filp);
+       put_device(&ev_file->dev->ib_dev.dev);
        return 0;
 }
 
@@ -2374,6 +2705,17 @@ static int devx_hot_unplug_async_cmd_event_file(struct 
ib_uobject *uobj,
 static int devx_hot_unplug_async_event_file(struct ib_uobject *uobj,
                                            enum rdma_remove_reason why)
 {
+       struct devx_async_event_file *ev_file =
+               container_of(uobj, struct devx_async_event_file,
+                            uobj);
+       struct devx_async_event_queue *ev_queue = &ev_file->ev_queue;
+
+       spin_lock_irq(&ev_queue->lock);
+       ev_queue->is_destroyed = 1;
+       spin_unlock_irq(&ev_queue->lock);
+
+       if (why == RDMA_REMOVE_DRIVER_REMOVE)
+               wake_up_interruptible(&ev_queue->poll_wait);
        return 0;
 };
 
diff --git a/include/uapi/rdma/mlx5_user_ioctl_verbs.h 
b/include/uapi/rdma/mlx5_user_ioctl_verbs.h
index 57beea4589e4..9500ff7363ef 100644
--- a/include/uapi/rdma/mlx5_user_ioctl_verbs.h
+++ b/include/uapi/rdma/mlx5_user_ioctl_verbs.h
@@ -67,5 +67,10 @@ enum mlx5_ib_uapi_devx_create_event_channel_flags {
        MLX5_IB_UAPI_DEVX_CREATE_EVENT_CHANNEL_FLAGS_OMIT_EV_DATA = 1 << 0,
 };
 
+struct mlx5_ib_uapi_devx_async_event_hdr {
+       __aligned_u64   cookie;
+       __u8            out_data[];
+};
+
 #endif
 
-- 
2.20.1

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