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
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