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H A D | zfcp_qdio.h | diff b3f0a1ee9e3986106869eec49b61b40abdccdcf7 Wed Apr 14 19:08:04 CEST 2021 Julian Wiedmann <jwi@linux.ibm.com> scsi: zfcp: Lift Request Queue tasklet & timer from qdio
The qdio layer currently provides its own infrastructure to scan for Request Queue completions & to report them to the device driver. This comes with several drawbacks - having an async tasklet & timer construct in qdio introduces additional lifetime complexity, and makes it harder to integrate them with the rest of the device driver. The timeouts are also currently hard-coded, and can't be tweaked without affecting other qdio drivers (ie. qeth).
But due to recent enhancements to the qdio layer, zfcp can actually take full control of the Request Queue completion processing. It merely needs to opt-out from the qdio layer mechanisms by setting the scan_threshold to 0, and then use qdio_inspect_queue() to scan for completions.
So re-implement the tasklet & timer mechanism in zfcp, while initially copying the scan conditions from qdio's handle_outbound() and qdio_outbound_tasklet(). One minor behavioural change is that zfcp_qdio_send() will unconditionally reduce the timeout to 1 HZ, rather than leaving it at 10 Hz if it was last armed by the tasklet. This just makes things more consistent. Also note that we can drop a lot of the accumulated cruft in qdio_outbound_tasklet(), as zfcp doesn't even use PCI interrupt requests any longer.
This also slightly touches the Response Queue processing, as qdio_get_next_buffers() will no longer implicitly scan for Request Queue completions. So complete the migration to qdio_inspect_queue() here as well and make the tasklet_schedule() visible.
Link: https://lore.kernel.org/r/018d3ddd029f8d6ac00cf4184880288c637c4fd1.1618417667.git.bblock@linux.ibm.com Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Signed-off-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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H A D | zfcp_qdio.c | diff b3f0a1ee9e3986106869eec49b61b40abdccdcf7 Wed Apr 14 19:08:04 CEST 2021 Julian Wiedmann <jwi@linux.ibm.com> scsi: zfcp: Lift Request Queue tasklet & timer from qdio
The qdio layer currently provides its own infrastructure to scan for Request Queue completions & to report them to the device driver. This comes with several drawbacks - having an async tasklet & timer construct in qdio introduces additional lifetime complexity, and makes it harder to integrate them with the rest of the device driver. The timeouts are also currently hard-coded, and can't be tweaked without affecting other qdio drivers (ie. qeth).
But due to recent enhancements to the qdio layer, zfcp can actually take full control of the Request Queue completion processing. It merely needs to opt-out from the qdio layer mechanisms by setting the scan_threshold to 0, and then use qdio_inspect_queue() to scan for completions.
So re-implement the tasklet & timer mechanism in zfcp, while initially copying the scan conditions from qdio's handle_outbound() and qdio_outbound_tasklet(). One minor behavioural change is that zfcp_qdio_send() will unconditionally reduce the timeout to 1 HZ, rather than leaving it at 10 Hz if it was last armed by the tasklet. This just makes things more consistent. Also note that we can drop a lot of the accumulated cruft in qdio_outbound_tasklet(), as zfcp doesn't even use PCI interrupt requests any longer.
This also slightly touches the Response Queue processing, as qdio_get_next_buffers() will no longer implicitly scan for Request Queue completions. So complete the migration to qdio_inspect_queue() here as well and make the tasklet_schedule() visible.
Link: https://lore.kernel.org/r/018d3ddd029f8d6ac00cf4184880288c637c4fd1.1618417667.git.bblock@linux.ibm.com Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Signed-off-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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