| Message ID | 20200119071432.18558-2-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | scsi: support bypass device busy check for some high end HBA with SSD | expand |
On 2020-01-18 23:14, Ming Lei wrote: > Cc: Bart Van Assche <bart.vanassche@wdc.com> As one can see in the .mailmap file in the kernel tree I use my @acm.org email address for kernel contributions. The above email address is no longer valid since I left WDC more than a year ago. This is something I have mentioned before. See also https://lore.kernel.org/linux-scsi/55c68a97-4393-fa63-e2da-d41a48237f96@acm.org/ > +static bool scsi_device_check_in_flight(struct request *rq, void *data, > + bool reserved) > +{ > + struct device_busy *busy = data; > + struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); > + > + if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state) && cmd->device == > + busy->dev) > + (busy->cnt)++; > + > + return true; > +} scsi_host_check_in_flight() is almost identical to the above function. Has it been considered to merge these two functions into a single function? Same comment for scsi_host_busy() and scsih_dev_busy(). Thanks, Bart.
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c index c597d544eb39..91766c172d8f 100644 --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c @@ -2994,6 +2994,36 @@ scsih_abort(struct scsi_cmnd *scmd) return r; } +struct device_busy { + struct scsi_device *dev; + unsigned int cnt; +}; + +static bool scsi_device_check_in_flight(struct request *rq, void *data, + bool reserved) +{ + struct device_busy *busy = data; + struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); + + if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state) && cmd->device == + busy->dev) + (busy->cnt)++; + + return true; +} + +static bool scsih_dev_busy(struct scsi_device *device) +{ + struct device_busy data = { + .dev = device, + .cnt = 0, + }; + + blk_mq_tagset_busy_iter(&device->host->tag_set, + scsi_device_check_in_flight, &data); + return data.cnt > 0; +} + /** * scsih_dev_reset - eh threads main device reset routine * @scmd: pointer to scsi command object @@ -3060,7 +3090,7 @@ scsih_dev_reset(struct scsi_cmnd *scmd) MPI2_SCSITASKMGMT_TASKTYPE_LOGICAL_UNIT_RESET, 0, 0, tr_timeout, tr_method); /* Check for busy commands after reset */ - if (r == SUCCESS && atomic_read(&scmd->device->device_busy)) + if (r == SUCCESS && scsih_dev_busy(scmd->device)) r = FAILED; out: sdev_printk(KERN_INFO, scmd->device, "device reset: %s scmd(0x%p)\n",
scsih_dev_reset() uses scsi_device->device_busy to check if there is inflight commands aimed to this LUN. Uses block layer's helper of blk_mq_tagset_busy_iter() to do that, so we can prepare for bypassing .device_busy for SSD since it is quite expensive to inc/dec the global atomic counter in IO path. With this change, no driver uses scsi_device->device_busy any more. Cc: Sathya Prakash <sathya.prakash@broadcom.com> Cc: Chaitra P B <chaitra.basappa@broadcom.com> Cc: Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Sumit Saxena <sumit.saxena@broadcom.com> Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Cc: Ewan D. Milne <emilne@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- drivers/scsi/mpt3sas/mpt3sas_scsih.c | 32 +++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)