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[PATCH 3.18 03/39] mtd: cfi: reduce stack size

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3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/include/linux/mtd/map.h
+++ b/include/linux/mtd/map.h
@@ -309,7 +309,17 @@ static inline map_word map_word_or(struc
 	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)
 {

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[PATCH 3.18 00/39] 3.18.53-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 28/39] USB: serial: sierra: fix bogus alternate-setting assumption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 18/39] USB: serial: keyspan_pda: fix receive sanity checks Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 34/39] ipv4, ipv6: ensure raw socket message is big enough to hold an IP header Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 10/39] mwifiex: debugfs: Fix (sometimes) off-by-1 SSID print Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 31/39] brcmfmac: Make skb header writable before use Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 26/39] USB: serial: mct_u232: fix modem-status error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 03/39] mtd: cfi: reduce stack size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:10 +0200
  [PATCH 3.18 06/39] powerpc/powernv: Fix opal_exit tracepoint opcode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:20 +0200
  [PATCH 3.18 05/39] cpupower: Fix turbo frequency reporting for pre-Sandy Bridge cores Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:20 +0200
  [PATCH 3.18 09/39] ARM: OMAP5 / DRA7: Fix HYP mode boot for thumb2 build Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:20 +0200
  [PATCH 3.18 20/39] USB: serial: ssu100: fix control-message error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:20 +0200
  [PATCH 3.18 08/39] power: supply: bq24190_charger: Call set_mode_host() on pm_resume() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-11 15:20 +0200

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