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author | Hannes Reinecke <hare@suse.de> | 2009-12-15 09:26:06 +0100 |
---|---|---|
committer | James Bottomley <James.Bottomley@suse.de> | 2010-01-18 10:48:09 -0600 |
commit | f2818663c82b7297ff4aa38cbddb870dc02f7104 (patch) | |
tree | ff088e90961a99d664a8923e48ef69d6289d48e2 /drivers | |
parent | e47c11c7a402a054a85cb917a6ed020f6b5fae04 (diff) | |
download | linux-3.10-f2818663c82b7297ff4aa38cbddb870dc02f7104.tar.gz linux-3.10-f2818663c82b7297ff4aa38cbddb870dc02f7104.tar.bz2 linux-3.10-f2818663c82b7297ff4aa38cbddb870dc02f7104.zip |
[SCSI] scsi_transport_fc: Remove capping from dev_loss_tmo
Currently dev_loss_tmo is capped by SCSI_DEVICE_BLOCK_MAX_TIMEOUT.
This causes problem with multipathing when the 'no_path_retry' setting
exceeds the dev_loss_tmo setting, as then the system might run into
a deadlock when all paths have been removed temporarily for longer
than dev_loss_tmo.
The principal reasons for the capping has been that we should
not allow a remote port to remain in status 'blocked' indefinitely,
so the capping is there to ensure that the port status is being reset
eventually.
However, the fast_io_fail_tmo will also move the remote port out of
the 'blocked' state, so for any HBA driver implementing both the
capping should really be on the fast_io_fail_tmo, and not on the
dev_loss_tmo.
This patch implements just that, ie the fast_io_fail_tmo is capped
to SCSI_DEVICE_BLOCK_TIMEOUT and the capping is removed from
dev_loss_tmo when fast_io_fail_tmo is set.
This allows us to synchronize the dev_loss_tmo setting to the
'no_path_retry' setting from multipathing thus avoiding the deadlock.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/scsi/scsi_transport_fc.c | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index 653f22a8deb..79660ee3e21 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -475,7 +475,8 @@ MODULE_PARM_DESC(dev_loss_tmo, "Maximum number of seconds that the FC transport should" " insulate the loss of a remote port. Once this value is" " exceeded, the scsi target is removed. Value should be" - " between 1 and SCSI_DEVICE_BLOCK_MAX_TIMEOUT."); + " between 1 and SCSI_DEVICE_BLOCK_MAX_TIMEOUT if" + " fast_io_fail_tmo is not set."); /* * Netlink Infrastructure @@ -842,9 +843,17 @@ store_fc_rport_dev_loss_tmo(struct device *dev, struct device_attribute *attr, (rport->port_state == FC_PORTSTATE_NOTPRESENT)) return -EBUSY; val = simple_strtoul(buf, &cp, 0); - if ((*cp && (*cp != '\n')) || - (val < 0) || (val > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)) + if ((*cp && (*cp != '\n')) || (val < 0)) return -EINVAL; + + /* + * If fast_io_fail is off we have to cap + * dev_loss_tmo at SCSI_DEVICE_BLOCK_MAX_TIMEOUT + */ + if (rport->fast_io_fail_tmo == -1 && + val > SCSI_DEVICE_BLOCK_MAX_TIMEOUT) + return -EINVAL; + i->f->set_rport_dev_loss_tmo(rport, val); return count; } @@ -925,9 +934,16 @@ store_fc_rport_fast_io_fail_tmo(struct device *dev, rport->fast_io_fail_tmo = -1; else { val = simple_strtoul(buf, &cp, 0); - if ((*cp && (*cp != '\n')) || - (val < 0) || (val >= rport->dev_loss_tmo)) + if ((*cp && (*cp != '\n')) || (val < 0)) return -EINVAL; + /* + * Cap fast_io_fail by dev_loss_tmo or + * SCSI_DEVICE_BLOCK_MAX_TIMEOUT. + */ + if ((val >= rport->dev_loss_tmo) || + (val > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)) + return -EINVAL; + rport->fast_io_fail_tmo = val; } return count; |