Re: [PATCH 03/14] usb: xhci: Unlock for command abort polling

[sashiko-bot@kernel.org]

> From: Michal Pecio <michal.pecio@gmail.com>
> 
> xhci_abort_cmd_ring() requests abort, waits for the CRR bit to clear,
> drops xhci->lock and waits for the Command Ring Stopped event.
> 
> The CRR wait timeout is 5 seconds as suggested by xHCI 4.6.1.2, which
> means that if the xHC fails to complete the operation at all, we poll
> with the lock held and IRQs disabled for several seconds. If any other
> CPU tries to acquire the lock, it will spin likewise. IRQs get delays,
> drivers log errors, tasks freeze, it's a mess.
> 
> So drop the lock earlier, before waiting for the CRR bit. It should be
> safe - the sole caller sets cmd_ring_state to CMD_RING_STATE_ABORTED
> before calling us, which will prevent others from ringing the command
> doorbell and interfering with the abort. Queuing new commands during
> [ ... ]
> 
> Reported-by: Pedro Fonseca <pedro@fonseca.com.pt>
> Link: https://lore.kernel.org/linux-usb/16f65081-5a3c-4c30-9811-9017796a3373@fonseca.com.pt/
> Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
> Signed-off-by: Mathias Nyman <mathias.nyman@intel.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261009095834.561578-1-mathias.nyman@linux.intel.com?part=3