linux-kernel - Re: [PATCH v3 06/16] nvme-fc: Do not wait in vain when unloading module

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Message-ID: <20231219043514.GG30580@lst.de>
Date: Tue, 19 Dec 2023 05:35:14 +0100
From: Christoph Hellwig <hch@....de>
To: Daniel Wagner <dwagner@...e.de>
Cc: linux-nvme@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Christoph Hellwig <hch@....de>, Sagi Grimberg <sagi@...mberg.me>,
	Keith Busch <kbusch@...nel.org>,
	James Smart <james.smart@...adcom.com>,
	Hannes Reinecke <hare@...e.de>
Subject: Re: [PATCH v3 06/16] nvme-fc: Do not wait in vain when unloading
 module

On Mon, Dec 18, 2023 at 04:30:54PM +0100, Daniel Wagner wrote:
> The module unload code will wait for a controller to be delete even when
> there is no controller and we wait for completion forever to happen.
> Thus only wait for the completion when there is a controller which
> needs to be removed.

This whole code looks fishy to me, and I suspect this patch only papers
over it.  Why do we this wait to start with?  If we've found that out and
documented it, the code really should be using a wait_event variant that
checks for the actual condition (no more controllers), because without
that you might still have a race otherwise.