Messages in this thread | | | From | David Howells <> | Subject | Re: [RFC][PATCH] fix short copy handling in copy_mc_pipe_to_iter() | Date | Tue, 14 Jun 2022 07:36:19 +0100 |
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Al Viro <viro@zeniv.linux.org.uk> wrote:
> What's wrong with > p_occupancy = pipe_occupancy(head, tail); > if (p_occupancy >= pipe->max_usage) > return 0; > else > return pipe->max_usage - p_occupancy;
Because "pipe->max_usage - p_occupancy" can be negative.
post_one_notification() is limited by pipe->ring_size, not pipe->max_usage.
The idea is to allow some slack in a watch pipe for the watch_queue code to use that userspace can't.
David
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