Re: Interrupts with SMP defined

Chris Loveland (
Thu, 5 Mar 1998 11:12:43 -0500 (EST)

On Thu, 5 Mar 1998, Thomas Schenk wrote:
> Dave,
> I believe if you read the message from Chris again, you will find
> that he is not proposing that he use the code above, but that the 2.0.33
> kernel already contains code that does this. Can you suggest how to
> correct the problem?
> Tom

The situation I was describing exists in the scsi code of the 2.1.88
kernel. The function do_sd_request in drivers/scsi/sd.c makes a call
to scsi_allocate_device in a section of code protected by a
spin_lock_irqsave(&io_request_lock, flags). scsi_allocate_device then
does the save_flags, restore_flags which turns interupts back on. On my
system this results in a hang when there is an ide interupt in
the section where interupts should be off because the ide interrupt
handler tries a spin_lock_irqsave(&io_request_lock, flags).


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