From: David Brownell <david-b@pacbell.net>
Date: Sun, 2 Apr 2006 18:37:40 +0000 (-0800)
Subject: [PATCH] SPI: spi bounce buffer has a minimum length
X-Git-Tag: firefly_0821_release~35765^2~6
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a9948b6194b46e489aa3b4d111d6dfd786c39c4b;p=firefly-linux-kernel-4.4.55.git

[PATCH] SPI: spi bounce buffer has a minimum length

Make sure that spi_write_then_read() can always handle at least 32 bytes
of transfer (total, both directions), minimizing one portability issue.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 94f5e8ed83a7..1168ef015887 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -522,7 +522,8 @@ int spi_sync(struct spi_device *spi, struct spi_message *message)
 }
 EXPORT_SYMBOL_GPL(spi_sync);
 
-#define	SPI_BUFSIZ	(SMP_CACHE_BYTES)
+/* portable code must never pass more than 32 bytes */
+#define	SPI_BUFSIZ	max(32,SMP_CACHE_BYTES)
 
 static u8	*buf;