On 01.02.24 17:40, Elliott, Robert (Servers) wrote:
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From: Lino Sanfilippo l.sanfilippo@kunbus.com Sent: Thursday, February 1, 2024 5:37 AM Subject: [PATCH] tpm,tpm_tis: Avoid warning splat at shutdown
If interrupts are not activated the work struct 'free_irq_work' is not initialized. This results in a warning splat at module shutdown.
Fix this by always initializing the work regardless of whether interrupts are activated or not.
That's using flush_work(), which just waits for one to complete. Is there any case where multiple work entries could be queued, and cancel_work_sync() would be necessary?
No. There is only one work struct (namely free_irq_work) and it can only be queued once at a time (note that schedule_work() does not queue the same work again if it is already queued).
tpm_tis_probe_irq() has a loop calling tpm_tis_probe_irq_single() for 3 to 15. Could each of those could trigger an interrupt storm and call tpm_tis_revert_interrupts(), which calls schedule_work()?
The iteration stops as soon as there is an interrupt found that "works" (i.e. as soon as one interrupt fires, see the "irq test" in tpm_tis_send()). If this irq starts a storm it is handled by the implemented irq storm handling and deactivated. No other interrupts are activated afterwards. So no, I do not see that multiple interrupt storms are possible at the same time.
Regards, Lino