IB/srp: Allow SRP disconnect through sysfs

Make it possible to disconnect the IB RC connection used by the SRP
protocol to communicate with a target.

Have the SRP transport layer create a sysfs "delete" attribute for
initiator drivers that support this functionality.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 21 insertions, 1 deletions

diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index 0d85f797141f..f379c7f3034c 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -38,7 +38,7 @@ struct srp_host_attrs {
 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
 
 #define SRP_HOST_ATTRS 0
-#define SRP_RPORT_ATTRS 2
+#define SRP_RPORT_ATTRS 3
 
 struct srp_internal {
         struct scsi_transport_template t;
@@ -116,6 +116,24 @@ show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 
+static ssize_t store_srp_rport_delete(struct device *dev,
+                                      struct device_attribute *attr,
+                                      const char *buf, size_t count)
+{
+        struct srp_rport *rport = transport_class_to_srp_rport(dev);
+        struct Scsi_Host *shost = dev_to_shost(dev);
+        struct srp_internal *i = to_srp_internal(shost->transportt);
+
+        if (i->f->rport_delete) {
+                i->f->rport_delete(rport);
+                return count;
+        } else {
+                return -ENOSYS;
+        }
+}
+
+static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
+
 static void srp_rport_release(struct device *dev)
 {
         struct srp_rport *rport = dev_to_rport(dev);
@@ -309,6 +327,8 @@ srp_attach_transport(struct srp_function_template *ft)
         count = 0;
         i->rport_attrs[count++] = &dev_attr_port_id;
         i->rport_attrs[count++] = &dev_attr_roles;
+        if (ft->rport_delete)
+                i->rport_attrs[count++] = &dev_attr_delete;
         i->rport_attrs[count++] = NULL;
         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));