Re: [PATCH 34/33] netfs: Use in_interrupt() not in_softirq()

Christoph Hellwig
2021-02-16T08:42:36Z

On Mon, Feb 15, 2021 at 10:46:23PM +0000, David Howells wrote:
> The in_softirq() in netfs_rreq_terminated() works fine for the cache being
> on a normal disk, as the completion handlers may get called in softirq
> context, but for an NVMe drive, the completion handler may get called in
> IRQ context.
>
> Fix to use in_interrupt() instead of in_softirq() throughout the read
> helpers, particularly when deciding whether to punt code that might sleep
> off to a worker thread.

We must not use either check, as they all are unreliable especially
for PREEMPT-RT.