Re: [PATCH] of: cache phandle nodes to decrease cost of of_find_node_by_phandle()

[Chintan Pandya]

On 2/1/2018 1:35 AM, frowand.l...@gmail.com wrote:

From: Frank Rowand <frank.row...@sony.com>

+
+static void of_populate_phandle_cache(void)
+{
+       unsigned long flags;
+       phandle max_phandle;
+       u32 nodes = 0;
+       struct device_node *np;
+
+       if (phandle_cache)
+               return;
+
+       max_phandle = live_tree_max_phandle();
+
+       raw_spin_lock_irqsave(&devtree_lock, flags);
+
+       for_each_of_allnodes(np)
+               nodes++;
+
+       /* sanity cap for malformed tree */
+       if (max_phandle > nodes)
+               max_phandle = nodes;

Shouldn't we speak up about this in kernel log ? May be WARN_ON() ?

+
+       phandle_cache = kzalloc((max_phandle + 1) * sizeof(*phandle_cache),
+                               GFP_KERNEL);

kzalloc (might_sleep) in critical context will break.

Anyways, will fix this locally and share test results.

Thanks,
Chintan

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