Please don't do Top-Posting ! see this: http://www.caliburn.nl/topposting.html On 2/9/06, Naveed Latif <kernelmail.naveed@xxxxxxxxx> wrote: > Hi, > In Process cotext you can hold spin_lock and also you can up().. And its > better to use spin_lock_irqsave intead of spin_lock in process context.. > spin_lock_irqsave is superset of all locks and can be used always, but its better to use __semphores__ in process context as you don't need to keep spinning to acquire lock rather can go to sleep ! Can consult "nreliable Guide To Locking" by Rusty Russell (http://www.kernel.org/pub/linux/kernel/people/rusty/kernel-locking/index.html) > > On 2/8/06, Hareesh Nagarajan <hareesh.nagarajan@xxxxxxxxx> wrote: > > > > In process context (and interrupt context, while we are at it) can we > > hold a spin lock and call up() (on a semaphore)? Apart from the usual > > issues pertaining with deadlocks - are we guaranteed that an up is a > > non-blocking operation? > > AFAIK, up can be called while holding spin_lock as up wake_ups the process which is/was waiting on the queue due to call of down and is non-blocking operation ! (CMIIW) -- Fawad Lateef -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
