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author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2008-02-15 21:29:02 +0100 |
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committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2008-02-16 15:40:35 +0100 |
commit | e80de3704ac30ddb7f9a12447a2ecee32ccd7880 (patch) | |
tree | 87ffc83df0d904b48af17177266ba604c2a3fd86 /drivers/firewire | |
parent | 7bb6bf7c8ba0b4ccfecaa00d6faea51b0bd42c8c (diff) | |
download | op-kernel-dev-e80de3704ac30ddb7f9a12447a2ecee32ccd7880.zip op-kernel-dev-e80de3704ac30ddb7f9a12447a2ecee32ccd7880.tar.gz |
firewire: fw-sbp2: enforce a retry of __scsi_add_device if bus generation changed
fw-sbp2 is unable to reconnect while performing __scsi_add_device
because there is only a single workqueue thread context available for
both at the moment. This should be fixed eventually.
An actual failure of __scsi_add_device is easy to handle, but an
incomplete execution of __scsi_add_device with an sdev returned would
remain undetected and leave the SBP-2 target unusable.
Therefore we use a workaround: If there was a bus reset during
__scsi_add_device (i.e. during the SCSI probe), we remove the new sdev
immediately, log out, and attempt login and SCSI probe again.
Tested-by: Jarod Wilson <jwilson@redhat.com> (earlier version)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'drivers/firewire')
-rw-r--r-- | drivers/firewire/fw-sbp2.c | 49 |
1 files changed, 35 insertions, 14 deletions
diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c index 323b03b..6d10934 100644 --- a/drivers/firewire/fw-sbp2.c +++ b/drivers/firewire/fw-sbp2.c @@ -762,22 +762,43 @@ static void sbp2_login(struct work_struct *work) sdev = __scsi_add_device(shost, 0, 0, scsilun_to_int(&eight_bytes_lun), lu); - if (IS_ERR(sdev)) { - smp_rmb(); /* generation may have changed */ - generation = device->generation; - smp_rmb(); /* node_id must not be older than generation */ + /* + * FIXME: We are unable to perform reconnects while in sbp2_login(). + * Therefore __scsi_add_device() will get into trouble if a bus reset + * happens in parallel. It will either fail or leave us with an + * unusable sdev. As a workaround we check for this and retry the + * whole login and SCSI probing. + */ - sbp2_send_management_orb(lu, device->node_id, generation, - SBP2_LOGOUT_REQUEST, lu->login_id, NULL); - /* - * Set this back to sbp2_login so we fall back and - * retry login on bus reset. - */ - PREPARE_DELAYED_WORK(&lu->work, sbp2_login); - } else { - lu->sdev = sdev; - scsi_device_put(sdev); + /* Reported error during __scsi_add_device() */ + if (IS_ERR(sdev)) + goto out_logout_login; + + scsi_device_put(sdev); + + /* Unreported error during __scsi_add_device() */ + smp_rmb(); /* get current card generation */ + if (generation != device->card->generation) { + scsi_remove_device(sdev); + goto out_logout_login; } + + /* No error during __scsi_add_device() */ + lu->sdev = sdev; + goto out; + + out_logout_login: + smp_rmb(); /* generation may have changed */ + generation = device->generation; + smp_rmb(); /* node_id must not be older than generation */ + + sbp2_send_management_orb(lu, device->node_id, generation, + SBP2_LOGOUT_REQUEST, lu->login_id, NULL); + /* + * If a bus reset happened, sbp2_update will have requeued + * lu->work already. Reset the work from reconnect to login. + */ + PREPARE_DELAYED_WORK(&lu->work, sbp2_login); out: sbp2_target_put(tgt); } |