summaryrefslogtreecommitdiff
path: root/drivers/pps/pps.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-22 01:41:04 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-22 01:41:04 +0400
commit21eaab6d19ed43e82ed39c8deb7f192134fb4a0e (patch)
treed995205afdcb7f47462bcd28067dc0c4ab0b7b02 /drivers/pps/pps.c
parent74e1a2a39355b2d3ae8c60c78d8add162c6d7183 (diff)
parent9e17df37d710f8998e9cb10a548304fe33d4a5c2 (diff)
downloadlinux-21eaab6d19ed43e82ed39c8deb7f192134fb4a0e.tar.xz
Merge tag 'tty-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial patches from Greg Kroah-Hartman: "Here's the big tty/serial driver patches for 3.9-rc1. More tty port rework and fixes from Jiri here, as well as lots of individual serial driver updates and fixes. All of these have been in the linux-next tree for a while." * tag 'tty-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (140 commits) tty: mxser: improve error handling in mxser_probe() and mxser_module_init() serial: imx: fix uninitialized variable warning serial: tegra: assume CONFIG_OF TTY: do not update atime/mtime on read/write lguest: select CONFIG_TTY to build properly. ARM defconfigs: add missing inclusions of linux/platform_device.h fb/exynos: include platform_device.h ARM: sa1100/assabet: include platform_device.h directly serial: imx: Fix recursive locking bug pps: Fix build breakage from decoupling pps from tty tty: Remove ancient hardpps() pps: Additional cleanups in uart_handle_dcd_change pps: Move timestamp read into PPS code proper pps: Don't crash the machine when exiting will do pps: Fix a use-after free bug when unregistering a source. pps: Use pps_lookup_dev to reduce ldisc coupling pps: Add pps_lookup_dev() function tty: serial: uartlite: Support uartlite on big and little endian systems tty: serial: uartlite: Fix sparse and checkpatch warnings serial/arc-uart: Miscll DT related updates (Grant's review comments) ... Fix up trivial conflicts, mostly just due to the TTY config option clashing with the EXPERIMENTAL removal.
Diffstat (limited to 'drivers/pps/pps.c')
-rw-r--r--drivers/pps/pps.c47
1 files changed, 43 insertions, 4 deletions
diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 2420d5af0583..6437703eb10f 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -247,12 +247,15 @@ static int pps_cdev_open(struct inode *inode, struct file *file)
struct pps_device *pps = container_of(inode->i_cdev,
struct pps_device, cdev);
file->private_data = pps;
-
+ kobject_get(&pps->dev->kobj);
return 0;
}
static int pps_cdev_release(struct inode *inode, struct file *file)
{
+ struct pps_device *pps = container_of(inode->i_cdev,
+ struct pps_device, cdev);
+ kobject_put(&pps->dev->kobj);
return 0;
}
@@ -274,8 +277,10 @@ static void pps_device_destruct(struct device *dev)
{
struct pps_device *pps = dev_get_drvdata(dev);
- /* release id here to protect others from using it while it's
- * still in use */
+ cdev_del(&pps->cdev);
+
+ /* Now we can release the ID for re-use */
+ pr_debug("deallocating pps%d\n", pps->id);
mutex_lock(&pps_idr_lock);
idr_remove(&pps_idr, pps->id);
mutex_unlock(&pps_idr_lock);
@@ -332,6 +337,7 @@ int pps_register_cdev(struct pps_device *pps)
goto del_cdev;
}
+ /* Override the release function with our own */
pps->dev->release = pps_device_destruct;
pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
@@ -352,11 +358,44 @@ free_idr:
void pps_unregister_cdev(struct pps_device *pps)
{
+ pr_debug("unregistering pps%d\n", pps->id);
+ pps->lookup_cookie = NULL;
device_destroy(pps_class, pps->dev->devt);
- cdev_del(&pps->cdev);
}
/*
+ * Look up a pps device by magic cookie.
+ * The cookie is usually a pointer to some enclosing device, but this
+ * code doesn't care; you should never be dereferencing it.
+ *
+ * This is a bit of a kludge that is currently used only by the PPS
+ * serial line discipline. It may need to be tweaked when a second user
+ * is found.
+ *
+ * There is no function interface for setting the lookup_cookie field.
+ * It's initialized to NULL when the pps device is created, and if a
+ * client wants to use it, just fill it in afterward.
+ *
+ * The cookie is automatically set to NULL in pps_unregister_source()
+ * so that it will not be used again, even if the pps device cannot
+ * be removed from the idr due to pending references holding the minor
+ * number in use.
+ */
+struct pps_device *pps_lookup_dev(void const *cookie)
+{
+ struct pps_device *pps;
+ unsigned id;
+
+ rcu_read_lock();
+ idr_for_each_entry(&pps_idr, pps, id)
+ if (cookie == pps->lookup_cookie)
+ break;
+ rcu_read_unlock();
+ return pps;
+}
+EXPORT_SYMBOL(pps_lookup_dev);
+
+/*
* Module stuff
*/