ibmvscsi: Prevent IO during partner login
Subsystems (3)
PATCH 1/1 ibmvscsi: Prevent IO during partner login
By setting the request_limit in send_srp_login to 1 we allowed login requests to be sent to the server adapter. If this was not an initial login, but was a login after a disconnect with the server, other I/O requests could attempt to be processed before the login occured. These I/O requests would fail, sometimes resulting in filesystems getting marked read-only.
To address this we can set the request_limit to 0 while doing the login and add an exception where login requests, along with task management events, are always passed to the server.
There is a case where the request_limit had already reached 0 would result in all events being sent rather than returning SCSI_MLQUEUE_HOST_BUSY; this has also been fixed by this patch.
--- drivers/scsi/ibmvscsi/ibmvscsi.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
drivers/scsi/ibmvscsi/ibmvscsi.c +14 -5
@@ -556,7 +556,7 @@ static int ibmvscsi_send_srp_event(struc unsigned long timeout) {u64 *crq_as_u64 = (u64 *) &evt_struct->crq; -int request_status; +int request_status =0 ;int rc;/* If we have exhausted our request limit, just fail this request,
@@ -574,6 +574,13 @@ static int ibmvscsi_send_srp_event(strucif (request_status <-1 ) goto send_error;/* Otherwise, we may have run out of requests. */ +/* If request limit was 0 when we started the adapter is in the +* process of performing a login with the server adapter, or +* we may have run out of requests. +*/ +else if (request_status ==-1 && + evt_struct->iu.srp.login_req.opcode !=SRP_LOGIN_REQ ) + goto send_busy;/* Abort and reset calls should make it through. * Nothing except abort and reset should use the last two * slots unless we had two or less to begin with.
@@ -633,7 +640,8 @@ static int ibmvscsi_send_srp_event(strucunmap_cmd_data (&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);free_event_struct (&hostdata->pool, evt_struct); -atomic_inc (&hostdata->request_limit); +if (request_status !=-1 ) +atomic_inc (&hostdata->request_limit);return SCSI_MLQUEUE_HOST_BUSY ; send_error:
@@ -927,10 +935,11 @@ static int send_srp_login(struct ibmvscs login->req_buf_fmt =SRP_BUF_FORMAT_DIRECT |SRP_BUF_FORMAT_INDIRECT ;spin_lock_irqsave (hostdata->host->host_lock, flags); -/* Start out with a request limit of 1, since this is negotiated in -* the login request we are just sending +/* Start out with a request limit of 0, since this is negotiated in +* the login request we are just sending and login requests always +* get sent by the driver regardless of request_limit. */ -atomic_set (&hostdata->request_limit,1 ); +atomic_set (&hostdata->request_limit,0 ); rc =ibmvscsi_send_srp_event (evt_struct, hostdata, init_timeout *2 );spin_unlock_irqrestore (hostdata->host->host_lock, flags);
The prior version of this patch introduced a problem for the error handler routines. Calling ibmvscsi_eh_reset_device during a initialization/login would result in the reset failing without need.
To avoid failing the eh_* functions while re-attaching to the server adapter this will retry for a period of time while ibmvscsi_send_srp_event
returns SCSI_MLQUEUE_HOST_BUSY.
By setting the request_limit in send_srp_login to 1 we allowed login requests to be sent to the server adapter. If this was not an initial login, but was a login after a disconnect with the server, other I/O requests could attempt to be processed before the login occured.
To address this we can set the request_limit to 0 while doing the login and add an exception where login requests, along with task management events, are always passed to the server.
There is a case where the request_limit had already reached 0 would result
in all events being sent rather than returning SCSI_MLQUEUE_HOST_BUSY; this
has also been fixed by this patch.
--- drivers/scsi/ibmvscsi/ibmvscsi.c | 59 ++++++++++++++++++++++++++++++++------- 1 file changed, 48 insertions(+), 11 deletions(-)
drivers/scsi/ibmvscsi/ibmvscsi.c +48 -11
@@ -556,7 +556,7 @@ static int ibmvscsi_send_srp_event(struc unsigned long timeout) {u64 *crq_as_u64 = (u64 *) &evt_struct->crq; -int request_status; +int request_status =0 ;int rc;/* If we have exhausted our request limit, just fail this request,
@@ -574,6 +574,13 @@ static int ibmvscsi_send_srp_event(strucif (request_status <-1 ) goto send_error;/* Otherwise, we may have run out of requests. */ +/* If request limit was 0 when we started the adapter is in the +* process of performing a login with the server adapter, or +* we may have run out of requests. +*/ +else if (request_status ==-1 && + evt_struct->iu.srp.login_req.opcode !=SRP_LOGIN_REQ ) + goto send_busy;/* Abort and reset calls should make it through. * Nothing except abort and reset should use the last two * slots unless we had two or less to begin with.
@@ -633,7 +640,8 @@ static int ibmvscsi_send_srp_event(strucunmap_cmd_data (&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);free_event_struct (&hostdata->pool, evt_struct); -atomic_inc (&hostdata->request_limit); +if (request_status !=-1 ) +atomic_inc (&hostdata->request_limit);return SCSI_MLQUEUE_HOST_BUSY ; send_error:
@@ -927,10 +935,11 @@ static int send_srp_login(struct ibmvscs login->req_buf_fmt =SRP_BUF_FORMAT_DIRECT |SRP_BUF_FORMAT_INDIRECT ;spin_lock_irqsave (hostdata->host->host_lock, flags); -/* Start out with a request limit of 1, since this is negotiated in -* the login request we are just sending +/* Start out with a request limit of 0, since this is negotiated in +* the login request we are just sending and login requests always +* get sent by the driver regardless of request_limit. */ -atomic_set (&hostdata->request_limit,1 ); +atomic_set (&hostdata->request_limit,0 ); rc =ibmvscsi_send_srp_event (evt_struct, hostdata, init_timeout *2 );spin_unlock_irqrestore (hostdata->host->host_lock, flags);
@@ -967,6 +976,7 @@ static int ibmvscsi_eh_abort_handler(strint rsp_rc;unsigned long flags;u16 lun =lun_from_dev (cmd->device); +unsigned long wait_switch =0 ;/* First, find this command in our sent list so we can figure * out the correct tag
@@ -1010,15 +1020,30 @@ static int ibmvscsi_eh_abort_handler(str tsk_mgmt->lun, tsk_mgmt->task_tag); evt->sync_srp = &srp_rsp; -init_completion (&evt->comp); - rsp_rc =ibmvscsi_send_srp_event (evt, hostdata, init_timeout *2 ); -spin_unlock_irqrestore (hostdata->host->host_lock, flags); + + wait_switch = jiffies + (init_timeout *HZ ); +do { +init_completion (&evt->comp); + rsp_rc =ibmvscsi_send_srp_event (evt, hostdata, init_timeout *2 ); + +if (rsp_rc !=SCSI_MLQUEUE_HOST_BUSY ) +break ; + +spin_unlock_irqrestore (hostdata->host->host_lock, flags); +msleep (10 ); +spin_lock_irqsave (hostdata->host->host_lock, flags); + }while (time_before (jiffies, wait_switch)); +if (rsp_rc !=0 ) { +free_event_struct (&found_evt->hostdata->pool, found_evt); +spin_unlock_irqrestore (hostdata->host->host_lock, flags);sdev_printk (KERN_ERR , cmd->device,"failed to send abort() event. rc=%d\n" , rsp_rc);return FAILED ; } +spin_unlock_irqrestore (hostdata->host->host_lock, flags); +wait_for_completion (&evt->comp);/* make sure we got a good response */
@@ -1090,6 +1115,7 @@ static int ibmvscsi_eh_device_reset_handint rsp_rc;unsigned long flags;u16 lun =lun_from_dev (cmd->device); +unsigned long wait_switch =0 ;spin_lock_irqsave (hostdata->host->host_lock, flags); evt =get_event_struct (&hostdata->pool);
@@ -1116,9 +1142,20 @@ static int ibmvscsi_eh_device_reset_hand tsk_mgmt->lun); evt->sync_srp = &srp_rsp; -init_completion (&evt->comp); - rsp_rc =ibmvscsi_send_srp_event (evt, hostdata, init_timeout *2 ); -spin_unlock_irqrestore (hostdata->host->host_lock, flags); + + wait_switch = jiffies + (init_timeout *HZ ); +do { +init_completion (&evt->comp); + rsp_rc =ibmvscsi_send_srp_event (evt, hostdata, init_timeout *2 ); +spin_unlock_irqrestore (hostdata->host->host_lock, flags); + +if (rsp_rc !=SCSI_MLQUEUE_HOST_BUSY ) +break ; + +msleep (10 ); +spin_lock_irqsave (hostdata->host->host_lock, flags); + }while (time_before (jiffies, wait_switch)); +if (rsp_rc !=0 ) {sdev_printk (KERN_ERR , cmd->device,"failed to send reset event. rc=%d\n" , rsp_rc);