path: root/kernel/time/posix-clock.c
AgeCommit message (Collapse)Author
2011-10-31kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructurePaul Gortmaker
These files were getting <linux/module.h> via an implicit non-obvious path, but we want to crush those out of existence since they cost time during compiles of processing thousands of lines of headers for no reason. Give them the lightweight header that just contains the EXPORT_SYMBOL infrastructure. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-04-18posix clocks: Replace mutex with reader/writer semaphoreRichard Cochran
A dynamic posix clock is protected from asynchronous removal by a mutex. However, using a mutex has the unwanted effect that a long running clock operation in one process will unnecessarily block other processes. For example, one process might call read() to get an external time stamp coming in at one pulse per second. A second process calling clock_gettime would have to wait for almost a whole second. This patch fixes the issue by using a reader/writer semaphore instead of a mutex. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/%3C20110330132421.GA31771%40riccoc20.at.omicron.at%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-12posix-clocks: Check write permissions in posix syscallsTorben Hohn
pc_clock_settime() and pc_clock_adjtime() do not check whether the fd was opened in write mode, so a clock can be set with a read only fd. [ tglx: We deliberately do not return -EPERM as we want this to be distingushable from the capability based permission check ] Signed-off-by: Torben Hohn <torbenh@gmx.de> LKML-Reference: <1299173174-348-4-git-send-email-torbenh@gmx.de> Cc: Richard Cochran <richard.cochran@omicron.at> Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-02-02posix clocks: Introduce dynamic clocksRichard Cochran
This patch adds support for adding and removing posix clocks. The clock lifetime cycle is patterned after usb devices. Each clock is represented by a standard character device. In addition, the driver may optionally implement custom character device operations. The posix clock and timer system calls listed below now work with dynamic posix clocks, as well as the traditional static clocks. The following system calls are affected: - clock_adjtime (brand new syscall) - clock_gettime - clock_getres - clock_settime - timer_create - timer_delete - timer_gettime - timer_settime [ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic to posix-clock.c and made all referenced functions static ] Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20110201134420.164172635@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>