[PATCH] rapidio/tsi721: fix bug in inbound doorbell handler

[Alexandre Bounine]

Fixes queue wrapping bug in Inbound Doorbell handling routine.

Signed-off-by: Alexandre Bounine <alexandre.bounine at idt.com>
Cc: Chul Kim <chul.kim at idt.com>
Cc: Matt Porter <mporter at kernel.crashing.org>
---
 This patch is applicable to kernel version 3.2 and after.

 drivers/rapidio/devices/tsi721.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c
index babbede..c746e26 100644
--- a/drivers/rapidio/devices/tsi721.c
+++ b/drivers/rapidio/devices/tsi721.c
@@ -406,13 +406,14 @@ static void tsi721_db_dpc(struct work_struct *work)
 	 */
 	mport = priv->mport;
 
-	wr_ptr = ioread32(priv->regs + TSI721_IDQ_WP(IDB_QUEUE));
-	rd_ptr = ioread32(priv->regs + TSI721_IDQ_RP(IDB_QUEUE));
+	wr_ptr = ioread32(priv->regs + TSI721_IDQ_WP(IDB_QUEUE)) % IDB_QSIZE;
+	rd_ptr = ioread32(priv->regs + TSI721_IDQ_RP(IDB_QUEUE)) % IDB_QSIZE;
 
 	while (wr_ptr != rd_ptr) {
 		idb_entry = (u64 *)(priv->idb_base +
 					(TSI721_IDB_ENTRY_SIZE * rd_ptr));
 		rd_ptr++;
+		rd_ptr %= IDB_QSIZE;
 		idb.msg = *idb_entry;
 		*idb_entry = 0;
 
-- 
1.7.8.4