powerpc/pseries/mobility: refactor node lookup during DT update

In pseries_devicetree_update(), with each call to ibm,update-nodes the
partition firmware communicates the node to be deleted or updated by
placing its phandle in the work buffer. Each of delete_dt_node(),
update_dt_node(), and add_dt_node() have duplicate lookups using the
phandle value and corresponding refcount management.

Move the lookup and of_node_put() into pseries_devicetree_update(),
and emit a warning on any failed lookups.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-29-nathanl@linux.ibm.com

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index e670180..ea4d6a6 100644 (file)
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -61,18 +61,10 @@ static int mobility_rtas_call(int token, char *buf, s32 scope)
        return rc;
 }
 
-static int delete_dt_node(__be32 phandle)
+static int delete_dt_node(struct device_node *dn)
 {
-       struct device_node *dn;
-
-       dn = of_find_node_by_phandle(be32_to_cpu(phandle));
-       if (!dn)
-               return -ENOENT;
-
        pr_debug("removing node %pOFfp\n", dn);
-
        dlpar_detach_node(dn);
-       of_node_put(dn);
        return 0;
 }
 
@@ -137,10 +129,9 @@ static int update_dt_property(struct device_node *dn, struct property **prop,
        return 0;
 }
 
-static int update_dt_node(__be32 phandle, s32 scope)
+static int update_dt_node(struct device_node *dn, s32 scope)
 {
        struct update_props_workarea *upwa;
-       struct device_node *dn;
        struct property *prop = NULL;
        int i, rc, rtas_rc;
        char *prop_data;
@@ -157,14 +148,8 @@ static int update_dt_node(__be32 phandle, s32 scope)
        if (!rtas_buf)
                return -ENOMEM;
 
-       dn = of_find_node_by_phandle(be32_to_cpu(phandle));
-       if (!dn) {
-               kfree(rtas_buf);
-               return -ENOENT;
-       }
-
        upwa = (struct update_props_workarea *)&rtas_buf[0];
-       upwa->phandle = phandle;
+       upwa->phandle = cpu_to_be32(dn->phandle);
 
        do {
                rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
@@ -224,26 +209,18 @@ static int update_dt_node(__be32 phandle, s32 scope)
                cond_resched();
        } while (rtas_rc == 1);
 
-       of_node_put(dn);
        kfree(rtas_buf);
        return 0;
 }
 
-static int add_dt_node(__be32 parent_phandle, __be32 drc_index)
+static int add_dt_node(struct device_node *parent_dn, __be32 drc_index)
 {
        struct device_node *dn;
-       struct device_node *parent_dn;
        int rc;
 
-       parent_dn = of_find_node_by_phandle(be32_to_cpu(parent_phandle));
-       if (!parent_dn)
-               return -ENOENT;
-
        dn = dlpar_configure_connector(drc_index, parent_dn);
-       if (!dn) {
-               of_node_put(parent_dn);
+       if (!dn)
                return -ENOENT;
-       }
 
        rc = dlpar_attach_node(dn, parent_dn);
        if (rc)
@@ -251,7 +228,6 @@ static int add_dt_node(__be32 parent_phandle, __be32 drc_index)
 
        pr_debug("added node %pOFfp\n", dn);
 
-       of_node_put(parent_dn);
        return rc;
 }
 
@@ -284,22 +260,31 @@ int pseries_devicetree_update(s32 scope)
                        data++;
 
                        for (i = 0; i < node_count; i++) {
+                               struct device_node *np;
                                __be32 phandle = *data++;
                                __be32 drc_index;
 
+                               np = of_find_node_by_phandle(be32_to_cpu(phandle));
+                               if (!np) {
+                                       pr_warn("Failed lookup: phandle 0x%x for action 0x%x\n",
+                                               be32_to_cpu(phandle), action);
+                                       continue;
+                               }
+
                                switch (action) {
                                case DELETE_DT_NODE:
-                                       delete_dt_node(phandle);
+                                       delete_dt_node(np);
                                        break;
                                case UPDATE_DT_NODE:
-                                       update_dt_node(phandle, scope);
+                                       update_dt_node(np, scope);
                                        break;
                                case ADD_DT_NODE:
                                        drc_index = *data++;
-                                       add_dt_node(phandle, drc_index);
+                                       add_dt_node(np, drc_index);
                                        break;
                                }
 
+                               of_node_put(np);
                                cond_resched();
                        }
                }