x86: Bump ZO_z_extra_bytes margin for zstd

[sfrench/cifs-2.6.git] / arch / x86 / boot / header.S

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 735ad7f21ab083d7e95b19906a3330d83ecd4743..6dbd7e9f74c9caf51a08dcc3cd2924982b2120f1 100644 (file)
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -539,8 +539,14 @@ pref_address:              .quad LOAD_PHYSICAL_ADDR        # preferred load addr
 # the size-dependent part now grows so fast.
 #
 # extra_bytes = (uncompressed_size >> 8) + 65536
+#
+# ZSTD compressed data grows by at most 3 bytes per 128K, and only has a 22
+# byte fixed overhead but has a maximum block size of 128K, so it needs a
+# larger margin.
+#
+# extra_bytes = (uncompressed_size >> 8) + 131072
 
-#define ZO_z_extra_bytes       ((ZO_z_output_len >> 8) + 65536)
+#define ZO_z_extra_bytes       ((ZO_z_output_len >> 8) + 131072)
 #if ZO_z_output_len > ZO_z_input_len
 # define ZO_z_extract_offset   (ZO_z_output_len + ZO_z_extra_bytes - \
                                 ZO_z_input_len)