devlink: implement shared buffer occupancy monitoring interface

User needs to monitor shared buffer occupancy. For that, he issues a
snapshot command in order to instruct hardware to catch current and
maximal occupancy values, and clear command in order to clear the
historical maximal values.

Also port-pool and tc-pool-bind command response messages are extended to
carry occupancy values.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 110 insertions, 6 deletions

diff --git a/include/net/devlink.h b/include/net/devlink.h
index e4c27473ee4f..be64218e0254 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -78,6 +78,18 @@ struct devlink_ops {
                                    u16 tc_index,
                                    enum devlink_sb_pool_type pool_type,
                                    u16 pool_index, u32 threshold);
+        int (*sb_occ_snapshot)(struct devlink *devlink,
+                               unsigned int sb_index);
+        int (*sb_occ_max_clear)(struct devlink *devlink,
+                                unsigned int sb_index);
+        int (*sb_occ_port_pool_get)(struct devlink_port *devlink_port,
+                                    unsigned int sb_index, u16 pool_index,
+                                    u32 *p_cur, u32 *p_max);
+        int (*sb_occ_tc_port_bind_get)(struct devlink_port *devlink_port,
+                                       unsigned int sb_index,
+                                       u16 tc_index,
+                                       enum devlink_sb_pool_type pool_type,
+                                       u32 *p_cur, u32 *p_max);
 };
 
 static inline void *devlink_priv(struct devlink *devlink)
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 9c1aa5783090..ba0073b26fa6 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -53,6 +53,10 @@ enum devlink_command {
         DEVLINK_CMD_SB_TC_POOL_BIND_NEW,
         DEVLINK_CMD_SB_TC_POOL_BIND_DEL,
 
+        /* Shared buffer occupancy monitoring commands */
+        DEVLINK_CMD_SB_OCC_SNAPSHOT,
+        DEVLINK_CMD_SB_OCC_MAX_CLEAR,
+
         /* add new commands above here */
 
         __DEVLINK_CMD_MAX,
@@ -119,6 +123,8 @@ enum devlink_attr {
         DEVLINK_ATTR_SB_POOL_THRESHOLD_TYPE,    /* u8 */
         DEVLINK_ATTR_SB_THRESHOLD,              /* u32 */
         DEVLINK_ATTR_SB_TC_INDEX,               /* u16 */
+        DEVLINK_ATTR_SB_OCC_CUR,                /* u32 */
+        DEVLINK_ATTR_SB_OCC_MAX,                /* u32 */
 
         /* add new attributes above here, update the policy in devlink.c */
 
diff --git a/net/core/devlink.c b/net/core/devlink.c
index aa0b9e1542e7..933e8d4d3968 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -280,6 +280,10 @@ devlink_sb_tc_index_get_from_info(struct devlink_sb *devlink_sb,
 #define DEVLINK_NL_FLAG_NEED_DEVLINK    BIT(0)
 #define DEVLINK_NL_FLAG_NEED_PORT       BIT(1)
 #define DEVLINK_NL_FLAG_NEED_SB         BIT(2)
+#define DEVLINK_NL_FLAG_LOCK_PORTS      BIT(3)
+        /* port is not needed but we need to ensure they don't
+         * change in the middle of command
+         */
 
 static int devlink_nl_pre_doit(const struct genl_ops *ops,
                                struct sk_buff *skb, struct genl_info *info)
@@ -306,6 +310,9 @@ static int devlink_nl_pre_doit(const struct genl_ops *ops,
                 }
                 info->user_ptr[0] = devlink_port;
         }
+        if (ops->internal_flags & DEVLINK_NL_FLAG_LOCK_PORTS) {
+                mutex_lock(&devlink_port_mutex);
+        }
         if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_SB) {
                 struct devlink_sb *devlink_sb;
 
@@ -324,7 +331,8 @@ static int devlink_nl_pre_doit(const struct genl_ops *ops,
 static void devlink_nl_post_doit(const struct genl_ops *ops,
                                  struct sk_buff *skb, struct genl_info *info)
 {
-        if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_PORT)
+        if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_PORT ||
+            ops->internal_flags & DEVLINK_NL_FLAG_LOCK_PORTS)
                 mutex_unlock(&devlink_port_mutex);
         mutex_unlock(&devlink_mutex);
 }
@@ -942,12 +950,13 @@ static int devlink_nl_sb_port_pool_fill(struct sk_buff *msg,
                                         enum devlink_command cmd,
                                         u32 portid, u32 seq, int flags)
 {
+        const struct devlink_ops *ops = devlink->ops;
         u32 threshold;
         void *hdr;
         int err;
 
-        err = devlink->ops->sb_port_pool_get(devlink_port, devlink_sb->index,
-                                             pool_index, &threshold);
+        err = ops->sb_port_pool_get(devlink_port, devlink_sb->index,
+                                    pool_index, &threshold);
         if (err)
                 return err;
 
@@ -966,6 +975,22 @@ static int devlink_nl_sb_port_pool_fill(struct sk_buff *msg,
         if (nla_put_u32(msg, DEVLINK_ATTR_SB_THRESHOLD, threshold))
                 goto nla_put_failure;
 
+        if (ops->sb_occ_port_pool_get) {
+                u32 cur;
+                u32 max;
+
+                err = ops->sb_occ_port_pool_get(devlink_port, devlink_sb->index,
+                                                pool_index, &cur, &max);
+                if (err && err != -EOPNOTSUPP)
+                        return err;
+                if (!err) {
+                        if (nla_put_u32(msg, DEVLINK_ATTR_SB_OCC_CUR, cur))
+                                goto nla_put_failure;
+                        if (nla_put_u32(msg, DEVLINK_ATTR_SB_OCC_MAX, max))
+                                goto nla_put_failure;
+                }
+        }
+
         genlmsg_end(msg, hdr);
         return 0;
 
@@ -1114,14 +1139,15 @@ devlink_nl_sb_tc_pool_bind_fill(struct sk_buff *msg, struct devlink *devlink,
                                 enum devlink_command cmd,
                                 u32 portid, u32 seq, int flags)
 {
+        const struct devlink_ops *ops = devlink->ops;
         u16 pool_index;
         u32 threshold;
         void *hdr;
         int err;
 
-        err = devlink->ops->sb_tc_pool_bind_get(devlink_port, devlink_sb->index,
-                                                tc_index, pool_type,
-                                                &pool_index, &threshold);
+        err = ops->sb_tc_pool_bind_get(devlink_port, devlink_sb->index,
+                                       tc_index, pool_type,
+                                       &pool_index, &threshold);
         if (err)
                 return err;
 
@@ -1144,6 +1170,24 @@ devlink_nl_sb_tc_pool_bind_fill(struct sk_buff *msg, struct devlink *devlink,
         if (nla_put_u32(msg, DEVLINK_ATTR_SB_THRESHOLD, threshold))
                 goto nla_put_failure;
 
+        if (ops->sb_occ_tc_port_bind_get) {
+                u32 cur;
+                u32 max;
+
+                err = ops->sb_occ_tc_port_bind_get(devlink_port,
+                                                   devlink_sb->index,
+                                                   tc_index, pool_type,
+                                                   &cur, &max);
+                if (err && err != -EOPNOTSUPP)
+                        return err;
+                if (!err) {
+                        if (nla_put_u32(msg, DEVLINK_ATTR_SB_OCC_CUR, cur))
+                                goto nla_put_failure;
+                        if (nla_put_u32(msg, DEVLINK_ATTR_SB_OCC_MAX, max))
+                                goto nla_put_failure;
+                }
+        }
+
         genlmsg_end(msg, hdr);
         return 0;
 
@@ -1326,6 +1370,30 @@ static int devlink_nl_cmd_sb_tc_pool_bind_set_doit(struct sk_buff *skb,
                                            pool_index, threshold);
 }
 
+static int devlink_nl_cmd_sb_occ_snapshot_doit(struct sk_buff *skb,
+                                               struct genl_info *info)
+{
+        struct devlink *devlink = info->user_ptr[0];
+        struct devlink_sb *devlink_sb = info->user_ptr[1];
+        const struct devlink_ops *ops = devlink->ops;
+
+        if (ops && ops->sb_occ_snapshot)
+                return ops->sb_occ_snapshot(devlink, devlink_sb->index);
+        return -EOPNOTSUPP;
+}
+
+static int devlink_nl_cmd_sb_occ_max_clear_doit(struct sk_buff *skb,
+                                                struct genl_info *info)
+{
+        struct devlink *devlink = info->user_ptr[0];
+        struct devlink_sb *devlink_sb = info->user_ptr[1];
+        const struct devlink_ops *ops = devlink->ops;
+
+        if (ops && ops->sb_occ_max_clear)
+                return ops->sb_occ_max_clear(devlink, devlink_sb->index);
+        return -EOPNOTSUPP;
+}
+
 static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
         [DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
         [DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
@@ -1439,6 +1507,24 @@ static const struct genl_ops devlink_nl_ops[] = {
                 .internal_flags = DEVLINK_NL_FLAG_NEED_PORT |
                                   DEVLINK_NL_FLAG_NEED_SB,
         },
+        {
+                .cmd = DEVLINK_CMD_SB_OCC_SNAPSHOT,
+                .doit = devlink_nl_cmd_sb_occ_snapshot_doit,
+                .policy = devlink_nl_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK |
+                                  DEVLINK_NL_FLAG_NEED_SB |
+                                  DEVLINK_NL_FLAG_LOCK_PORTS,
+        },
+        {
+                .cmd = DEVLINK_CMD_SB_OCC_MAX_CLEAR,
+                .doit = devlink_nl_cmd_sb_occ_max_clear_doit,
+                .policy = devlink_nl_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK |
+                                  DEVLINK_NL_FLAG_NEED_SB |
+                                  DEVLINK_NL_FLAG_LOCK_PORTS,
+        },
 };
 
 /**