RDMA/uverbs: Refactor rdma_counter_set_auto_mode and __counter_set_mode

Success is returned in the following flows:
 * New mode is the same as the current one.
 * Switched to new mode and there are no bound counters yet.

Link: https://lore.kernel.org/r/20210318110502.673676-1-leon@kernel.org
Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Reviewed-by: Mark Zhang <markzhang@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/core/counters.c b/drivers/infiniband/core/counters.c
index a284a35..1549335 100644 (file)
--- a/drivers/infiniband/core/counters.c
+++ b/drivers/infiniband/core/counters.c
@@ -14,10 +14,12 @@ static int __counter_set_mode(struct rdma_port_counter *port_counter,
                              enum rdma_nl_counter_mode new_mode,
                              enum rdma_nl_counter_mask new_mask)
 {
-       if (new_mode == RDMA_COUNTER_MODE_AUTO && port_counter->num_counters)
-               if (new_mask & ~ALL_AUTO_MODE_MASKS ||
-                   port_counter->mode.mode != RDMA_COUNTER_MODE_NONE)
+       if (new_mode == RDMA_COUNTER_MODE_AUTO) {
+               if (new_mask & (~ALL_AUTO_MODE_MASKS))
                        return -EINVAL;
+               if (port_counter->num_counters)
+                       return -EBUSY;
+       }
 
        port_counter->mode.mode = new_mode;
        port_counter->mode.mask = new_mask;
@@ -32,14 +34,17 @@ static int __counter_set_mode(struct rdma_port_counter *port_counter,
  * @mask: Mask to configure
  * @extack: Message to the user
  *
- * Return 0 on success.
+ * Return 0 on success. If counter mode wasn't changed then it is considered
+ * as success as well.
+ * Return -EBUSY when changing to auto mode while there are bounded counters.
+ *
  */
 int rdma_counter_set_auto_mode(struct ib_device *dev, u32 port,
                               enum rdma_nl_counter_mask mask,
                               struct netlink_ext_ack *extack)
 {
-       enum rdma_nl_counter_mode mode = RDMA_COUNTER_MODE_AUTO;
        struct rdma_port_counter *port_counter;
+       enum rdma_nl_counter_mode mode;
        int ret;
 
        port_counter = &dev->port_data[port].port_counter;
@@ -47,25 +52,26 @@ int rdma_counter_set_auto_mode(struct ib_device *dev, u32 port,
                return -EOPNOTSUPP;
 
        mutex_lock(&port_counter->lock);
-       if (mask) {
-               ret = __counter_set_mode(port_counter, mode, mask);
-               if (ret)
-                       NL_SET_ERR_MSG(
-                               extack,
-                               "Turning on auto mode is not allowed when there is bound QP");
+       if (mask)
+               mode = RDMA_COUNTER_MODE_AUTO;
+       else
+               mode = (port_counter->num_counters) ? RDMA_COUNTER_MODE_MANUAL :
+                                                     RDMA_COUNTER_MODE_NONE;
+
+       if (port_counter->mode.mode == mode &&
+           port_counter->mode.mask == mask) {
+               ret = 0;
                goto out;
        }
 
-       if (port_counter->mode.mode != RDMA_COUNTER_MODE_AUTO) {
-               ret = -EINVAL;
-               goto out;
-       }
+       ret = __counter_set_mode(port_counter, mode, mask);
 
-       mode = (port_counter->num_counters) ? RDMA_COUNTER_MODE_MANUAL :
-                                                   RDMA_COUNTER_MODE_NONE;
-       ret = __counter_set_mode(port_counter, mode, 0);
 out:
        mutex_unlock(&port_counter->lock);
+       if (ret == -EBUSY)
+               NL_SET_ERR_MSG(
+                       extack,
+                       "Modifying auto mode is not allowed when there is a bound QP");
        return ret;
 }