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authorStephan Gerhold <stephan@gerhold.net>2023-06-14 21:20:43 +0200
committerRob Herring <robh@kernel.org>2023-06-20 09:34:58 -0600
commit4cea2821882b06cd2c9c896d501f58746c16a90b (patch)
tree8098cee3f6157228bed7cde4e2d3a7dec4dda90d
parent83ba7361e168cd7b24aa95d2aefb4e31e3cc6cd0 (diff)
of: reserved_mem: Use stable allocation order
sort() in Linux is based on heapsort which is not a stable sort algorithm - equal elements are being reordered. For reserved memory in the device tree this happens mainly for dynamic allocations: They do not have an address to sort with, so they are reordered somewhat randomly when adding/removing other unrelated reserved memory nodes. Functionally this is not a big problem, but it's confusing during development when all the addresses change after adding unrelated reserved memory nodes. Make the order stable by sorting dynamic allocations according to the node order in the device tree. Static allocations are not affected by this because they are still sorted by their (fixed) address. Signed-off-by: Stephan Gerhold <stephan@gerhold.net> Link: https://lore.kernel.org/r/20230510-dt-resv-bottom-up-v2-2-aeb2afc8ac25@gerhold.net Signed-off-by: Rob Herring <robh@kernel.org>
-rw-r--r--drivers/of/of_reserved_mem.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 7f892c3dcc63..7ec94cfcbddb 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -268,6 +268,11 @@ static int __init __rmem_cmp(const void *a, const void *b)
if (ra->size > rb->size)
return 1;
+ if (ra->fdt_node < rb->fdt_node)
+ return -1;
+ if (ra->fdt_node > rb->fdt_node)
+ return 1;
+
return 0;
}