Hello, Currently I don't see any users of aio cancellation facility (except a USB gadget driver). I have a SATA controller and disk that both support the NCQ command aborts, and I am thinking of ways to implement aio cancellation on these devices in the kernel. The way I see it, at the time user requests for a command to be cancelled, it could be be in one of the 2 places: 1. Sitting in block layer elevator queues, and not yet submitted it to the SCSI subsystem (scsi_dispatch_cmd() not yet called). [I see some solutions available to this https://lkml.org/lkml/2013/5/13/615 ] 2. Submitted to the SCSI subsystem / LLD, but pending in the LLD SW or the HW (scsi_done() not yet called). This part is what I am keen on adding. My line of thought (10000 ft view) currently is, that I should: A) Do the necessary plumbing (through the block & scsi layers) such that the kiocb_cancel() should eventually result in a call to the eh_abort_handler() for the LLD for that particular command. This should (atleast in my theory) let the LLD know that it needs to cancel the command, and can do whatever it needs to do in order to cancel it. B) Add a helper function in libata that allocates & initializes a new "Queue Management - Abort (0x63)" ATA command, that the LLD's eh_abort_handler() can choose to use in case it sees that the command is already sent to the disk drive. It can then send this new ata_queued_cmd to abort the pending command to the drive. This is of course optional and to be used at LLD(s) discretion. Comments? Thoughts? I'd appreciate if you could please let me know if I'm on the right track or totally off? Thanks, Rajat -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
