Hello, I have another doubt here. When i do a spin_lock_bh and then after taking that lock if a sock_alloc_skb call is issued, the alloc buf fails. In the function sock_alloc_skb(), there is a check for in_interrupt(). After acquiring a spin_lock_bh the in_interrupt is returning true and the alloc_skb fails In that case even if i create a new kernel thread and share the linked list between ppp module and kernel thread and if i use the spin_lock to protect my list. It again will fail inside the sock_sendmsg function(because of the sock_alloc_skb function) if i try to use the same buffer received by ppp module. Since this is in the data path, in the new kernel thread i dont want to make a copy of the buffer i want to pass the same buffer Isnt the spinlock similar to the semaphores what we normally use in other RTOS..?? Thanks and Regards, Vanitha > Thanks for your mail. I basically want to send the packets > received by the synchronous ppp tty module (ppp_synctty.c) > to a socket application. Since the ppp transmit function is called > from interrupt context, i am not able to invoke the sock_sendmsg > call. > i don't know much about the ppp core, so i assume the above statement is correct > So i thought of creating a new kernel thread which will have a queue > so that from the sync ppp tty module i will post the packets to this > queue. From this kernel thread i can write the message to the > socket. > > well looks like all you need is a static data structure like: buffer / linked list. They both need to be protected by a spinlock (due to the interrupt context issues). My idea is: the kernel_thread goes to sleep (in a wait queue) waiting for a packet. When a packet is received from the ppp core you enqueue it in the choosen data structre (buffer/linked list), and wake the kernel_thread. If you're working against the 2.6, take a look at the workqueue ... maybe you can simplify your code by using on of such queue. Hope these helps. _____________________________________________________________ Are you a Techie? Get Your Free Tech Email Address Now! Visit http://www.TechEmail.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
