[3.16.y-ckt stable] Patch "mISDN: fix a loop count" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    mISDN: fix a loop count

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt23.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From 3d254cb5b3a490a9bc0602d9004109d37923fe3a Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter at oracle.com>
Date: Tue, 15 Dec 2015 13:07:52 +0300
Subject: mISDN: fix a loop count

commit 40d24c4d8a7430aa4dfd7a665fa3faf3b05b673f upstream.

There are two issue here.
1)  cnt starts as maxloop + 1 so all these loops iterate one more time
    than intended.
2)  At the end of the loop we test for "if (maxloop && !cnt)" but for
    the first two loops, we end with cnt equal to -1.  Changing this to
    a pre-op means we end with cnt set to 0.

Fixes: cae86d4a4e56 ('mISDN: Add driver for Infineon ISDN chipset family')
Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/isdn/hardware/mISDN/mISDNipac.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/isdn/hardware/mISDN/mISDNipac.c b/drivers/isdn/hardware/mISDN/mISDNipac.c
index ccd7d851be26..92cf6fcd20ac 100644
--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -1164,7 +1164,7 @@ mISDNipac_irq(struct ipac_hw *ipac, int maxloop)

 	if (ipac->type & IPAC_TYPE_IPACX) {
 		ista = ReadIPAC(ipac, ISACX_ISTA);
-		while (ista && cnt--) {
+		while (ista && --cnt) {
 			pr_debug("%s: ISTA %02x\n", ipac->name, ista);
 			if (ista & IPACX__ICA)
 				ipac_irq(&ipac->hscx[0], ista);
@@ -1176,7 +1176,7 @@ mISDNipac_irq(struct ipac_hw *ipac, int maxloop)
 		}
 	} else if (ipac->type & IPAC_TYPE_IPAC) {
 		ista = ReadIPAC(ipac, IPAC_ISTA);
-		while (ista && cnt--) {
+		while (ista && --cnt) {
 			pr_debug("%s: ISTA %02x\n", ipac->name, ista);
 			if (ista & (IPAC__ICD | IPAC__EXD)) {
 				istad = ReadISAC(isac, ISAC_ISTA);
@@ -1194,7 +1194,7 @@ mISDNipac_irq(struct ipac_hw *ipac, int maxloop)
 			ista = ReadIPAC(ipac, IPAC_ISTA);
 		}
 	} else if (ipac->type & IPAC_TYPE_HSCX) {
-		while (cnt) {
+		while (--cnt) {
 			ista = ReadIPAC(ipac, IPAC_ISTAB + ipac->hscx[1].off);
 			pr_debug("%s: B2 ISTA %02x\n", ipac->name, ista);
 			if (ista)
@@ -1205,7 +1205,6 @@ mISDNipac_irq(struct ipac_hw *ipac, int maxloop)
 				mISDNisac_irq(isac, istad);
 			if (0 == (ista | istad))
 				break;
-			cnt--;
 		}
 	}
 	if (cnt > maxloop) /* only for ISAC/HSCX without PCI IRQ test */