Re: Sleeping thread not receive signal until it wakes up

[Jan Engelhardt]

On Mar 7 2007 08:19, linux-os (Dick Johnson) wrote:
>
>Later versions of the kernel lock the kernel when an ioctl() is
>entered. This means that if you sleep in the ioctl(), nothing
>will get scheduled.

Later versions of the kernel also have an ->unlocked_ioctl method,
which is probably better than below's approach [which is akin to
FreeBSD's DROP_GIANT/PICKUP_GIANT].

>You can do the following (possibly unsafe) in your ioctl():
>
>     int locked = kernel_locked();
>
>     ......... code
>     ......... code
>
>     if(locked)  // Before sleeping section
>        unlock_kernel();
>     .......... sleeping code
>     if(locked)  // After sleeping section
>         lock_kernel();
>
>

Jan
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