From a0899d4df534d2bcf671b0f647b809842309a9ae Mon Sep 17 00:00:00 2001
From: Hans de Goede <j.w.r.degoede@hhs.nl>
Date: Sun, 20 Jan 2008 11:12:26 +0100
Subject: [SCSI] sd: add fix for devices with last sector access problems

This patch adds a new scsi_device flag (last_sector_bug) for devices
which contain a bug where the device crashes when the last sector is
read in a larger then 1 sector read.

This is for example the case with sdcards in the HP PSC1350 printer
cardreader and in the HP PSC1610 printer cardreader.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 drivers/scsi/sd.c | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'drivers/scsi')

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 212f6bcfd457..24eba3118b5a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -395,6 +395,15 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
 		goto out;
 	}
 
+	/*
+	 * Some devices (some sdcards for one) don't like it if the
+	 * last sector gets read in a larger then 1 sector read.
+	 */
+	if (unlikely(sdp->last_sector_bug &&
+	    rq->nr_sectors > sdp->sector_size / 512 &&
+	    block + this_count == get_capacity(disk)))
+		this_count -= sdp->sector_size / 512;
+
 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu\n",
 					(unsigned long long)block));
 
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