Linux-kernel mailing list archive 1998-42,: Re: get_vm_area and GFP_KERNEL

# Re: get_vm_area and GFP_KERNEL

Benjamin C.R. LaHaise (blah@kvack.org)
Thu, 22 Oct 1998 15:41:37 -0400 (EDT)

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On Thu, 22 Oct 1998, David Grothe wrote:

...
> The problem: If these routines are called from a bottom half task queue
> routine then kmalloc thinks that it is being called from interrupt level
> without GFP_ATOMIC and prints a message to that effect.

But who is calling ioremap or vremap from a bottom half? That isn't
permitted! Device drivers are supposed to setup their mappings ahead of
time, right?

> Would any harm be done by changing this?

Yes, reliability of vmalloc/ioremap would be degraded, whereas many of the
callers expect the system to make a reasonable attempt to perform the
operation (we all know about the sound & floppy driver transient failures
due to DMA). If such a hack must be added, it should use something like
the gfp_any macro.

-ben

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