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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-21 13:41:04 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-21 13:41:04 -0800 |
commit | 21eaab6d19ed43e82ed39c8deb7f192134fb4a0e (patch) | |
tree | d995205afdcb7f47462bcd28067dc0c4ab0b7b02 /drivers/pps/pps.c | |
parent | 74e1a2a39355b2d3ae8c60c78d8add162c6d7183 (diff) | |
parent | 9e17df37d710f8998e9cb10a548304fe33d4a5c2 (diff) | |
download | linux-21eaab6d19ed43e82ed39c8deb7f192134fb4a0e.tar.bz2 |
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.c | 47 |
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 */ |