Patchwork [3.5.y.z,extended,stable] Patch "pps: Use pps_lookup_dev to reduce ldisc coupling" has been added to staging queue

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Submitter Luis Henriques
Date Feb. 26, 2013, 4:14 p.m.
Message ID <1361895259-28455-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/223315/
State New
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Comments

Luis Henriques - Feb. 26, 2013, 4:14 p.m.
This is a note to let you know that I have just added a patch titled

    pps: Use pps_lookup_dev to reduce ldisc coupling

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From 8fde127c5b9ee6db81ef5218cf9fefb13166ed96 Mon Sep 17 00:00:00 2001
From: George Spelvin <linux@horizon.com>
Date: Sun, 10 Feb 2013 04:41:56 -0500
Subject: [PATCH] pps: Use pps_lookup_dev to reduce ldisc coupling

commit 03a7ffe4e542310838bac70ef85acc17536b6d7c upstream.

Now that N_TTY uses tty->disc_data for its private data,
'subclass' ldiscs cannot use ->disc_data for their own private data.
(This is a regression is v3.8-rc1)

Use pps_lookup_dev to associate the tty with the pps source instead.

This fixes a crashing regression in 3.8-rc1.

Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/pps/clients/pps-ldisc.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

--
1.8.1.2

Patch

diff --git a/drivers/pps/clients/pps-ldisc.c b/drivers/pps/clients/pps-ldisc.c
index 79451f2..60cee9e 100644
--- a/drivers/pps/clients/pps-ldisc.c
+++ b/drivers/pps/clients/pps-ldisc.c
@@ -31,7 +31,7 @@ 
 static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
 				struct pps_event_time *ts)
 {
-	struct pps_device *pps = (struct pps_device *)tty->disc_data;
+	struct pps_device *pps = pps_lookup_dev(tty);

 	BUG_ON(pps == NULL);

@@ -67,9 +67,9 @@  static int pps_tty_open(struct tty_struct *tty)
 		pr_err("cannot register PPS source \"%s\"\n", info.path);
 		return -ENOMEM;
 	}
-	tty->disc_data = pps;
+	pps->lookup_cookie = tty;

-	/* Should open N_TTY ldisc too */
+	/* Now open the base class N_TTY ldisc */
 	ret = alias_n_tty_open(tty);
 	if (ret < 0) {
 		pr_err("cannot open tty ldisc \"%s\"\n", info.path);
@@ -81,7 +81,6 @@  static int pps_tty_open(struct tty_struct *tty)
 	return 0;

 err_unregister:
-	tty->disc_data = NULL;
 	pps_unregister_source(pps);
 	return ret;
 }
@@ -90,11 +89,10 @@  static void (*alias_n_tty_close)(struct tty_struct *tty);

 static void pps_tty_close(struct tty_struct *tty)
 {
-	struct pps_device *pps = (struct pps_device *)tty->disc_data;
+	struct pps_device *pps = pps_lookup_dev(tty);

 	alias_n_tty_close(tty);

-	tty->disc_data = NULL;
 	dev_info(pps->dev, "removed\n");
 	pps_unregister_source(pps);
 }