Re: [RFC] IB/srp: export reset-host via sysfs

From: Gioh Kim
Date: Tue Oct 04 2016 - 11:22:41 EST

On 04.10.2016 16:24, Bart Van Assche wrote:
On 10/04/16 07:00, Gioh Kim wrote:
Standard SCSI device has host_reset sysfs interface.
This patch exports the host_reset interface for upper layer.

Signed-off-by: Gioh Kim <>
drivers/infiniband/ulp/srp/ib_srp.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 3322ed7..92e6c3f 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -2628,6 +2628,15 @@ static int srp_reset_device(struct scsi_cmnd *scmnd)
return SUCCESS;

+static int srp_scsi_host_reset(struct Scsi_Host *shost, int reset_type)
+ struct srp_target_port *target = host_to_target(shost);
+ shost_printk(KERN_EMERG, target->scsi_host, PFX "SRP reset_host called\n");
+ return srp_reconnect_rport(target->rport);
static int srp_reset_host(struct scsi_cmnd *scmnd)
struct srp_target_port *target = host_to_target(scmnd->device->host);
@@ -2858,6 +2867,7 @@ static struct scsi_host_template srp_template = {
.use_clustering = ENABLE_CLUSTERING,
.shost_attrs = srp_host_attrs,
.track_queue_depth = 1,
+ .host_reset = srp_scsi_host_reset,

Hello Gioh,

A patch description should not only explain what is changed but also why a change is considered useful. Why do you think it would be useful to allow users to trigger a call of srp_reconnect_rport() through sysfs instead of using the functionality that is already available through sysfs, namely removing a SCSI host and reconnecting?
Hello Bart,

It's my mistake to miss 0000-cover-letter.patch file including description.

I'm testing SCSI devices which are exported by the remote servers via IB network. I know that SCSI error handling mechanism calls reset-host when something wrong happens. But the SCSI error handling tries sending ABORT commands and other actions before resetting host. I found that those ABORT commands could generate more stress on the remove server. So I need to reset SCSI host (which mean reconnecting) when the remote server starts to become slow or have some problem to handle IO.

And I think I can use some utilities for SCSI device, such like sg3 utils, to handle srp connection.

Thank you for your reply.

Best regards,
Gioh Kim