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[3.16-stable,02/14] mtd: cfi: reduce stack size

Message ID 20170509100502.1358298-3-arnd@arndb.de
State New
Headers show
Series [3.16-stable,01/14] staging: r8192ee: prorperly format warning message | expand

Commit Message

Arnd Bergmann May 9, 2017, 10:04 a.m. UTC 
Commit d09957fbb4d0b059b3176b510540df69048ad170 upstream.

The cfi_staa_write_buffers function uses a large amount of kernel stack
whenever CONFIG_MTD_MAP_BANK_WIDTH_32 is set, and that results in a
warning on ARM allmodconfig builds:

drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_write_buffers':
drivers/mtd/chips/cfi_cmdset_0020.c:651:1: warning: the frame size of 1208 bytes is larger than 1024 bytes [-Wframe-larger-than=]

It turns out that this is largely a result of a suboptimal implementation
of map_word_andequal(). Replacing this function with a straightforward
one reduces the stack size in this function by exactly 200 bytes,
shrinks the .text segment for this file from 27648 bytes to 26608 bytes,
and makes the warning go away.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 include/linux/mtd/map.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

-- 
2.9.0
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Patch

diff --git a/include/linux/mtd/map.h b/include/linux/mtd/map.h
index b501e9cd7d3e..db1dba23aed2 100644
--- a/include/linux/mtd/map.h
+++ b/include/linux/mtd/map.h
@@ -317,7 +317,17 @@  static inline map_word map_word_or(struct map_info *map, map_word val1, map_word
 	return r;
 }
 
-#define map_word_andequal(m, a, b, z) map_word_equal(m, z, map_word_and(m, a, b))
+static inline int map_word_andequal(struct map_info *map, map_word val1, map_word val2, map_word val3)
+{
+	int i;
+
+	for (i = 0; i < map_words(map); i++) {
+		if ((val1.x[i] & val2.x[i]) != val3.x[i])
+			return 0;
+	}
+
+	return 1;
+}
 
 static inline int map_word_bitsset(struct map_info *map, map_word val1, map_word val2)
 {