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From: Jakub Kicinski <kuba@kernel.org>
To: Brett Creeley <brett.creeley@amd.com>
Cc: <davem@davemloft.net>, <edumazet@google.com>, <pabeni@redhat.com>,
	<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<shannon.nelson@amd.com>
Subject: Re: [PATCH net] pds_core: Fix pdsc_check_pci_health function to print warning
Date: Fri, 22 Mar 2024 18:02:51 -0700	[thread overview]
Message-ID: <20240322180251.69167fd1@kernel.org> (raw)
In-Reply-To: <20240321063954.18711-1-brett.creeley@amd.com>

On Wed, 20 Mar 2024 23:39:54 -0700 Brett Creeley wrote:
> When the driver notices fw_status == 0xff it tries to perform a PCI
> reset on itself via pci_reset_function() in the context of the driver's
> health thread. However, pdsc_reset_prepare calls
> pdsc_stop_health_thread(), which attempts to stop/flush the health
> thread. This results in a deadlock because the stop/flush will never
> complete since the driver called pci_reset_function() from the health
> thread context. Fix this by changing the pdsc_check_pci_health_function()
> to print a dev_warn() once every fw_down/fw_up cycle and requiring the
> user to perform a reset on the device via sysfs's reset interface,
> reloading the driver, rebinding the device, etc.

Dunno, to call PCI reset you don't need much device context.
Perhaps you could allocate a work entry, throw it onto a per-driver
workqueue, and return. Basically some minimal viable way to
"asynchronously" call pci_reset_function()?
You can take a ref on the device so it doesn't disappear.
And flush that queue on module unload.

  parent reply	other threads:[~2024-03-23  1:02 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-21  6:39 [PATCH net] pds_core: Fix pdsc_check_pci_health function to print warning Brett Creeley
2024-03-22 11:09 ` Simon Horman
2024-03-23  1:02 ` Jakub Kicinski [this message]
2024-04-02 17:02   ` Brett Creeley

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