Hi, please find my response inline. See if it suits your requirement. >-----Original Message----- >From: kernelnewbies-bounce@xxxxxxxxxxxx [mailto:kernelnewbies- >bounce@xxxxxxxxxxxx] On Behalf Of Garcia Jérémie >Sent: Monday, June 27, 2005 6:51 PM >To: tomazb@xxxxxxxxxxx >Cc: kernelnewbies@xxxxxxxxxxxx >Subject: Linux question , please help a newbie! > >Hi Tom, >I'm looking for a solution to a problem you posted on the net 2 years ago. >I need to be able to interrupt a task that is waiting for a semaphore to be >free. >Indeed I use "down_interruptible()" and I'd like to be able to tell to the >task >after a period of time : "give up, awake and do something else". One possible way is to declare a timer which will send a signal to task blocked on down_interruptible after a specified period of time. This will cause the down_interruptible to return and you can do something else. In case the down_interrutible succeeds the signal will be ignored. I have tested the above functionality with this sample code: =========================== int tid; struct semaphore test_sem; void test_fn(){ /* send the signal to bring the task out of down call*/ kill_proc(tid, SIGALRM /*any signal which the task can ignore*/, 1); } struct timer_list test_timer; int init_module(){ init_MUTEX(&test_sem); tid=current->pid; /*this down call is to make sure that any subsequent call to down_interruptible blocks :-) */ if(down_interruptible(&test_sem)) printk("failed to acquired the semaphore\n"); else printk("sem acquired\n"); init_timer(&test_timer); test_timer.data=0; test_timer.function=test_fn; add_timer(&test_timer) /*try to acquire the sem again, which will block it and bring the signal into picture*/ if(down_interruptible(&test_sem)){ printk("interrupted\n"); } else printk("semaphore acquired"); up(&test_sem); return 0; } void cleanup_module() { } MODULE_LICENSE("GPL"); ============================== >You did not give the solution on the list. So do you have it or do you >remember what to >do cause it was a long time ago lol! >Tks, Jérémie Hope this helps. Sanjay ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://sanjayku.blogspot.com > >-- >Kernelnewbies: Help each other learn about the Linux kernel. >Archive: http://mail.nl.linux.org/kernelnewbies/ >FAQ: http://kernelnewbies.org/faq/ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
