From 31c8025fac3d8bbff7ce4602338d88efc2d7972c Mon Sep 17 00:00:00 2001
From: David Brazdil <dbrazdil@google.com>
Date: Fri, 17 Sep 2021 14:14:23 +0100
Subject: [PATCH] of: restricted dma: Fix condition for rmem init
of_dma_set_restricted_buffer fails to handle negative return values from
of_property_count_elems_of_size, e.g. when the property does not exist.
This results in an attempt to assign a non-existent reserved memory
region to the device and a warning being printed. Fix the condition to
take negative values into account.
Fixes: f3cfd136aef0 ("of: restricted dma: Don't fail device probe on rmem init failure")
Cc: Will Deacon <will@kernel.org>
Signed-off-by: David Brazdil <dbrazdil@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210917131423.2760155-1-dbrazdil@google.com
Signed-off-by: Rob Herring <robh@kernel.org>
---
drivers/of/device.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 5b043ee30824..b0800c260f64 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -85,7 +85,11 @@ of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
break;
}
- if (i != count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
+ /*
+ * Attempt to initialize a restricted-dma-pool region if one was found.
+ * Note that count can hold a negative error code.
+ */
+ if (i < count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
}