This patchset implements a new SCSI EH command timeout handler which will be sending command aborts inline without actually engaging SCSI EH. SCSI EH will only be invoked if command abort fails.
In addition the commands will be returned directly if the command abort succeeded, cutting down recovery times dramatically. With the original SCSI EH I got: # time dd if=/dev/zero of=/dev/dm-2 bs=4k count=4k oflag=direct 4096+0 records in 4096+0 records out 16777216 bytes (17 MB) copied, 142.652 s, 118 kB/s real 2m22.657s user 0m0.013s sys 0m0.145s With this patchset I got: # time dd if=/dev/zero of=/dev/dm-2 bs=4k count=4k oflag=direct 4096+0 records in 4096+0 records out 16777216 bytes (17 MB) copied, 52.1579 s, 322 kB/s real 0m52.163s user 0m0.012s sys 0m0.145s Test was to disable RSCN on the target port, disable the target port, and then start the 'dd' command as indicated. As a proof-of-concept I've also enabled the new timeout handler for virtio, so that things can be tested out more easily. As requested I've also hooked in the new SCSI timeout handler to SAS. Changes to the original version: - Use a private list in scsi_eh_abort_handler to avoid list starvation (pointed out by Joern Engel) - Terminate command aborts when the first abort fails - Do not attempt command aborts if the host is already in recovery or if the device is removed. - Flush abort workqueue if the device is removed. Changes to v2: - Removed eh_entry initialisation - Convert to per-command workqueue Comments etc are welcome. Hannes Reinecke (9): scsi: Fix erratic device offline during EH blk-timeout: add BLK_EH_SCHEDULED return code scsi: improved eh timeout handler virtio_scsi: Enable new EH timeout handler libsas: Enable new EH timeout handler mptsas: Enable new EH timeout handler mpt2sas: Enable new EH timeout handler mpt3sas: Enable new EH timeout handler scsi_transport_fc: Enable new EH timeout handler drivers/message/fusion/mptsas.c | 3 +- drivers/message/fusion/mptscsih.c | 7 ++ drivers/message/fusion/mptscsih.h | 1 + drivers/scsi/libsas/sas_scsi_host.c | 2 +- drivers/scsi/mpt2sas/mpt2sas_scsih.c | 13 ++- drivers/scsi/mpt3sas/mpt3sas_scsih.c | 11 +++ drivers/scsi/scsi.c | 1 + drivers/scsi/scsi_error.c | 171 ++++++++++++++++++++++++++++++----- drivers/scsi/scsi_priv.h | 2 + drivers/scsi/scsi_transport_fc.c | 2 +- drivers/scsi/virtio_scsi.c | 8 ++ include/linux/blkdev.h | 1 + include/scsi/scsi_cmnd.h | 2 + 13 files changed, 199 insertions(+), 25 deletions(-) -- 1.7.12.4 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
