FC_REMOTE_PORT_DELET(9) SCSI mid layer FC_REMOTE_PORT_DELET(9)NAMEfc_remote_port_delete - notifies the fc transport that a remote port is
no longer in existence.
SYNOPSIS
void fc_remote_port_delete(struct fc_rport * rport);
ARGUMENTS
rport
The remote port that no longer exists
DESCRIPTION
The LLDD calls this routine to notify the transport that a remote port
is no longer part of the topology. Note: Although a port may no longer
be part of the topology, it may persist in the remote ports displayed
by the fc_host. We do this under 2 conditions: 1) If the port was a
scsi target, we delay its deletion by “blocking” it. This allows the
port to temporarily disappear, then reappear without disrupting the
SCSI device tree attached to it. During the “blocked” period the port
will still exist. 2) If the port was a scsi target and disappears for
longer than we expect, we´ll delete the port and the tear down the SCSI
device tree attached to it. However, we want to semi-persist the target
id assigned to that port if it eventually does exist. The port
structure will remain (although with minimal information) so that the
target id bindings remails.
If the remote port is not an FCP Target, it will be fully torn down and
deallocated, including the fc_remote_port class device.
If the remote port is an FCP Target, the port will be placed in a
temporary blocked state. From the LLDD´s perspective, the rport no
longer exists. From the SCSI midlayer´s perspective, the SCSI target
exists, but all sdevs on it are blocked from further I/O. The following
is then expected.
If the remote port does not return (signaled by a LLDD call to
fc_remote_port_add) within the dev_loss_tmo timeout, then the scsi
target is removed - killing all outstanding i/o and removing the scsi
devices attached ot it. The port structure will be marked Not Present
and be partially cleared, leaving only enough information to recognize
the remote port relative to the scsi target id binding if it later
appears. The port will remain as long as there is a valid binding (e.g.
until the user changes the binding type or unloads the scsi host with
the binding).
If the remote port returns within the dev_loss_tmo value (and matches
according to the target id binding type), the port structure will be
reused. If it is no longer a SCSI target, the target will be torn down.
If it continues to be a SCSI target, then the target will be unblocked
(allowing i/o to be resumed), and a scan will be activated to ensure
that all luns are detected.
Called from normal process context only - cannot be called from
interrupt.
NOTES
This routine assumes no locks are held on entry.
AUTHORS
James Bottomley <James.Bottomley@hansenpartnership.com>
Author.
Rob Landley <rob@landley.net>
Author.
COPYRIGHTKernel Hackers Manual 2.6. November 2013 FC_REMOTE_PORT_DELET(9)