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@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit 7eb2a0151e7c8a95d1be33a923718fb690452c61)
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/drivers/isdn/hardware/mISDN/mISDNipac.c b/drivers/isdn/hardware/mISDN/mISDNipac.c
index 613ba043537254eb57307beb8591317661fc1549..12dfb908049a40678ca3433b745162e501fc27bb 100644 (file)
--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -1154,7 +1154,7 @@ 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);
@@ -1166,7 +1166,7 @@ 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);
@@ -1184,7 +1184,7 @@ 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)
@@ -1195,7 +1195,6 @@ 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 */