[PATCH 3.2 13/70] mISDN: fix a loop count

Ben Hutchings
2016-01-18T03:38:04Z

From: Dan Carpenter <dan.carpenter@oracle.com>

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@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/isdn/hardware/mISDN/mISDNipac.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -1156,7 +1156,7 @@ mISDNipac_irq(struct ipac_hw *ipac, int

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);
@@ -1168,7 +1168,7 @@ mISDNipac_irq(struct ipac_hw *ipac, int
}
} 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);
@@ -1186,7 +1186,7 @@ mISDNipac_irq(struct ipac_hw *ipac, int
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)
@@ -1197,7 +1197,6 @@ mISDNipac_irq(struct ipac_hw *ipac, int
mISDNisac_irq(isac, istad);
if (0 == (ista | istad))
break;
- cnt--;
}
}
if (cnt > maxloop) /* only for ISAC/HSCX without PCI IRQ test */