From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Mon, 25 Sep 2006 23:57:42 +0000 (-0700)
Subject: [SCSI] aic7xxx: fix byte I/O order in ahd_inw
X-Git-Tag: v2.6.19-rc1~4^2~34
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7b75b990e3cb33fd529640d589e77950e72a607c;p=linux-2.6

[SCSI] aic7xxx: fix byte I/O order in ahd_inw

Comment says "Read high byte first as some registers increment..."
but code doesn't guarantee that, I think:
	return ((ahd_inb(ahd, port+1) << 8) | ahd_inb(ahd, port));
Compiler can reorder it.

Make the order explicit.

Signed-off-by: Denis Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

Fixed rejections and added aic7xxx code
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
---

diff --git a/drivers/scsi/aic7xxx/aic79xx_inline.h b/drivers/scsi/aic7xxx/aic79xx_inline.h
index 8ad3ce945b..a3266e066c 100644
--- a/drivers/scsi/aic7xxx/aic79xx_inline.h
+++ b/drivers/scsi/aic7xxx/aic79xx_inline.h
@@ -527,7 +527,8 @@ ahd_inw(struct ahd_softc *ahd, u_int port)
 	 * or have other side effects when the low byte is
 	 * read.
 	 */
-	return ((ahd_inb(ahd, port+1) << 8) | ahd_inb(ahd, port));
+	uint16_t r = ahd_inb(ahd, port+1) << 8;
+	return r | ahd_inb(ahd, port);
 }
 
 static __inline void
diff --git a/drivers/scsi/aic7xxx/aic7xxx_inline.h b/drivers/scsi/aic7xxx/aic7xxx_inline.h
index 2cc8a17ed8..8e1954cdd8 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_inline.h
+++ b/drivers/scsi/aic7xxx/aic7xxx_inline.h
@@ -300,7 +300,8 @@ ahc_fetch_transinfo(struct ahc_softc *ahc, char channel, u_int our_id,
 static __inline uint16_t
 ahc_inw(struct ahc_softc *ahc, u_int port)
 {
-	return ((ahc_inb(ahc, port+1) << 8) | ahc_inb(ahc, port));
+	uint16_t r = ahc_inb(ahc, port+1) << 8;
+	return r | ahc_inb(ahc, port);
 }
 
 static __inline void