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TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; DKIM_TRACE(0.00)[suse.de:+]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Rspamd-Queue-Id: 4B4E93E6D0 X-Spam-Flag: NO X-Spam-Score: -4.51 X-Spam-Level: On 2/17/26 19:25, Mohamed Khalfella wrote: > On Mon 2026-02-16 13:43:51 +0100, Hannes Reinecke wrote: [ .. ] >> >> We really would need some indicator whether 'ccr' is supported at all. > > Why do we need this indicator, other than exporting it via sysfs? > To avoid false positives. >> Using the number of available CCR commands would be an option, if though >> that would require us to keep two counters (one for the number of >> possible outstanding CCRs, and one for the number of actual outstanding >> CCRs.). > > Like mentioned above ctrl->ccr_limit gives us the number of ccrs > available now. It is not 100% indicator if CCR is supported or not, but > it is enough to implement CCR. A second counter can help us skip trying > CCR if we know impacted controller does not support it. > > Do you think it is worth it? > Yes. The problem is that we want to get towards TP8028 compliance, which forces us to wait for 2*KATO + CQT before requests on the failed patch can be retried. That will cause a _noticeable_ stall on the application side. And the only way to shorten that is CCR; once we get confirmation from CCR we can start retrying immediately. At the same time the current implementation only waits for 1*KATO before retrying, so there will be regression if we switch to TP8028-compliant KATO handling for systems not supporting CCR. So we can (and should) use CCR as the determining factor whether we want to switch to TP8028-compliant behaviour or stick with the original implementation. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich