Hemant/ Sanjay, Sanjay is talking about the fact that, in the "loading" function itself the semaphore is made up although it has not been "sema_init". That said I think they are just "idiot modules" that have been put in and of course may not work really perfectly. Thanks, Vishwas -----Original Message----- From: kernelnewbies-bounce@xxxxxxxxxxxx [mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On Behalf Of Hemant Mohapatra Sent: Friday, July 01, 2005 10:55 AM To: Sanjay Kumar, Noida Cc: kernelnewbies@xxxxxxxxxxxx Subject: Re: KernelNewbies Wikki On 7/1/05, Sanjay Kumar, Noida <sanjayku@xxxxxxxxxxx> wrote: > Hi, > if the kmalloc fails for hello_msg, why do we need to release > the semaphore.This is the code snippet: > if (!hello_msg){ > up(&hello_sem); > return -ENOMEM; > } Please read the code carefully again: static ssize_t hello_write(struct inode *inode, const char __user *user_buf, size_t len, loff_t offset) { .. down(&hello_sem); --> semaphore initialized here. if (hello_msg) { kfree(hello_msg); hello_msg = kmalloc(len+1, GFP_KERNEL); if (!hello_msg) { up(&hello_sem); --> if fails, change back to original semval and return return -ENOMEM; .. } Where is the problem? ./h www.embedded-tutorials.com - Embedded Linux Tutorials -- 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/
