From: QiaoChong <qiaochong@loongson.cn>
Date: Sat, 9 Feb 2019 20:59:07 +0000 (+0000)
Subject: parport_pc: fix find_superio io compare code, should use equal test.
X-Git-Tag: Ubuntu-4.15.0-61.68~2740
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=6fb67869f529e5fb613bc7751f21a8c7a1509d45;p=mirror_ubuntu-bionic-kernel.git

parport_pc: fix find_superio io compare code, should use equal test.

BugLink: https://bugs.launchpad.net/bugs/1837952

commit 21698fd57984cd28207d841dbdaa026d6061bceb upstream.

In the original code before 181bf1e815a2 the loop was continuing until
it finds the first matching superios[i].io and p->base.
But after 181bf1e815a2 the logic changed and the loop now returns the
pointer to the first mismatched array element which is then used in
get_superio_dma() and get_superio_irq() and thus returning the wrong
value.
Fix the condition so that it now returns the correct pointer.

Fixes: 181bf1e815a2 ("parport_pc: clean up the modified while loops using for")
Cc: Alan Cox <alan@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: QiaoChong <qiaochong@loongson.cn>
[rewrite the commit message]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
---

diff --git a/drivers/parport/parport_pc.c b/drivers/parport/parport_pc.c
index 380916bff9e0..dee5b9e35ffd 100644
--- a/drivers/parport/parport_pc.c
+++ b/drivers/parport/parport_pc.c
@@ -1377,7 +1377,7 @@ static struct superio_struct *find_superio(struct parport *p)
 {
 	int i;
 	for (i = 0; i < NR_SUPERIOS; i++)
-		if (superios[i].io != p->base)
+		if (superios[i].io == p->base)
 			return &superios[i];
 	return NULL;
 }