Re: [PATCH 2/3] of/numa: fix a memory@ dt node can only contains one memory block

On Thu, May 26, 2016 at 10:36 PM, Leizhen (ThunderTown)
[off-list ref] wrote:

On 2016/5/26 21:13, Rob Herring wrote:

quoted

On Thu, May 26, 2016 at 10:43:58AM +0800, Zhen Lei wrote:

quoted

For a normal memory@ devicetree node, its reg property can contains more
memory blocks.

Because we don't known how many memory blocks maybe contained, so we try
from index=0, increase 1 until error returned(the end).

Signed-off-by: Zhen Lei <redacted>
---
 drivers/of/of_numa.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/of/of_numa.c b/drivers/of/of_numa.c
index 21d831f..2c5f249 100644
--- a/drivers/of/of_numa.c
+++ b/drivers/of/of_numa.c

@@ -63,7 +63,7 @@ static int __init of_numa_parse_memory_nodes(void)
     struct device_node *np = NULL;
     struct resource rsrc;
     u32 nid;
-    int r = 0;
+    int i, r = 0;

     for (;;) {
             np = of_find_node_by_type(np, "memory");

@@ -82,17 +82,27 @@ static int __init of_numa_parse_memory_nodes(void)
                     /* some other error */
                     break;

-            r = of_address_to_resource(np, 0, &rsrc);
-            if (r) {
-                    pr_err("NUMA: bad reg property in memory node\n");
-                    break;
+            for (i = 0; ; i++) {
+                    r = of_address_to_resource(np, i, &rsrc);
+                    if (r) {
+                            /* reached the end of of_address */
+                            if (i > 0) {
+                                    r = 0;
+                                    break;
+                            }
+
+                            pr_err("NUMA: bad reg property in memory node\n");
+                            goto finished;
+                    }
+
+                    r = numa_add_memblk(nid, rsrc.start,
+                                        rsrc.end - rsrc.start + 1);
+                    if (r)
+                            goto finished;
             }
-
-            r = numa_add_memblk(nid, rsrc.start,
-                                rsrc.end - rsrc.start + 1);
-            if (r)
-                    break;
     }
+
+finished:
     of_node_put(np);

This function can be simplified down to:

      for_each_node_by_type(np, "memory") {

OK, That's good.

quoted

              r = of_property_read_u32(np, "numa-node-id", &nid);
              if (r == -EINVAL)
                      /*
                       * property doesn't exist if -EINVAL, continue
                       * looking for more memory nodes with
                       * "numa-node-id" property
                       */
                      continue;

Hi, everybody:
    If some "memory" node contains "numa-node-id", but some others missed. Can we simply ignored it?
I think we should break out too, and faking to only have node0.

Continuing to work is probably better than not.

quoted

              else if (r)
                      /* some other error */
                      break;

              r = of_address_to_resource(np, 0, &rsrc);
              for (i = 0; !r; i++, r = of_address_to_resource(np, i,

But r(non-zero) is just break this loop, the original is break the outer for (;;) loop

It is not really the kernel's job to validate the DT. If there's
random things in it then kernel's behavior is undefined.

How about as below?

        for_each_node_by_type(np, "memory") {
                ... ...

                for (i = 0; !of_address_to_resource(np, i, &rsrc); i++) {
                        r = numa_add_memblk(nid, rsrc.start,
                                            rsrc.end - rsrc.start + 1);
                        if (r)
                                goto finished;
                }

                if (!i)
                        pr_err("NUMA: bad reg property in memory node\n");
        }

finished:

Please try to avoid the goto. You can check r in the outer loop too.

Rob
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