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Message-Id: <1427723723-12676-4-git-send-email-Sreekanth.Reddy@avagotech.com>
Date: Mon, 30 Mar 2015 19:25:06 +0530
From: Sreekanth Reddy <sreekanth.reddy@...gotech.com>
To: jejb@...nel.org, hch@...radead.org
Cc: martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
JBottomley@...allels.com, Sathya.Prakash@...gotech.com,
kashyap.desai@...gotech.com, linux-kernel@...r.kernel.org,
thenzl@...hat.com, Sreekanth Reddy <Sreekanth.Reddy@...gotech.com>
Subject: [PATCH 03/20] [SCSI] mpt3sas: Added module parameter 'unblock_io' to unblock IO's during disk addition
During hot-plugging of a disk(having a flaky link), the disk addition
stops and any further disk addition or removal doesn't happen on that controller.
This is because, when driver receives DELAY_NOT_RESPONDING event for a disk while
it is undergoing addition at the SCSI Transport layer, the driver would block the I/O to that disk
resulting in a deadlock. i.e the disk addition work couldn't be completed at the SCSI Transport Layer
as it can't send any I/Os (such as Inquiry, Report LUNs etc) to the disk as I/Os are blocked to this drive.
Also any subsequent device removal (TARGET_NOT_RESPONDING) or link update(RC_PHY_CHANGED) event
couldn't be processed as they are in the queue to get processed after disk addition event.
Description of Change:
To handle such cases, unblock the I/Os to the disk in ISR context if the disk is undergoing
addition. The I/Os would get unblocked only if the driver receives RC_PHY_CHANGED reason
code when the device addition is within the SAS Transport layer.
An module parameter 'unblock_io' is introduced which needs to be set to have this
functionality enabled. By default this functionality is disabled.
Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@...gotech.com>
---
drivers/scsi/mpt3sas/mpt3sas_base.h | 4 +-
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 63 +++++++++++++++++++++++++++++---
drivers/scsi/mpt3sas/mpt3sas_transport.c | 14 +++++++
3 files changed, 75 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h b/drivers/scsi/mpt3sas/mpt3sas_base.h
index 6b8d8f1..8dac951 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -294,7 +294,8 @@ struct _internal_cmd {
* @responding: used in _scsih_sas_device_mark_responding
* @fast_path: fast path feature enable bit
* @pfa_led_on: flag for PFA LED status
- *
+ * @pend_sas_rphy_add: flag to check if device is in sas_rphy_add()
+ * addition routine
*/
struct _sas_device {
struct list_head list;
@@ -315,6 +316,7 @@ struct _sas_device {
u8 responding;
u8 fast_path;
u8 pfa_led_on;
+ u8 pend_sas_rphy_add;
};
/**
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 5a97e32..2f45e8b 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -111,6 +111,11 @@ static int missing_delay[2] = {-1, -1};
module_param_array(missing_delay, int, NULL, 0);
MODULE_PARM_DESC(missing_delay, " device missing delay , io missing delay");
+static int unblock_io;
+module_param(unblock_io, int, 0);
+MODULE_PARM_DESC(unblock_io,
+"unblocks IO if set to 1 when device is undergoing addition (default=0)");
+
/* scsi-mid layer global parmeter is max_report_luns, which is 511 */
#define MPT3SAS_MAX_LUN (16895)
static u64 max_lun = MPT3SAS_MAX_LUN;
@@ -2606,6 +2611,34 @@ _scsih_ublock_io_device(struct MPT3SAS_ADAPTER *ioc, u64 sas_address)
}
}
+/*
+ *_scsih_ublock_io_device_to_running - set the device state to SDEV_RUNNING
+ *@ioc: per adapter object
+ *@..._addr: sas address
+ *
+ *unblock the device to receive IO during device addition. Device
+ *responsiveness is not checked before unblocking
+ */
+static void
+_scsih_ublock_io_device_to_running(struct MPT3SAS_ADAPTER *ioc, u64 sas_address)
+{
+ struct MPT3SAS_DEVICE *sas_device_priv_data;
+ struct scsi_device *sdev;
+
+ shost_for_each_device(sdev, ioc->shost) {
+ sas_device_priv_data = sdev->hostdata;
+ if (!sas_device_priv_data)
+ continue;
+ if (sas_device_priv_data->sas_target->sas_address
+ != sas_address)
+ continue;
+ if (sas_device_priv_data->block) {
+ sas_device_priv_data->block = 0;
+ scsi_internal_device_unblock(sdev, SDEV_RUNNING);
+ }
+ }
+}
+
/**
* _scsih_block_io_all_device - set the device state to SDEV_BLOCK
* @ioc: per adapter object
@@ -2713,20 +2746,22 @@ _scsih_block_io_to_children_attached_to_ex(struct MPT3SAS_ADAPTER *ioc,
}
/**
- * _scsih_block_io_to_children_attached_directly
+ * _scsih_handle_io_to_children_attached_directly
* @ioc: per adapter object
* @event_data: topology change event data
*
- * This routine set sdev state to SDEV_BLOCK for all devices
+ * This routine set sdev state to SDEV_BLOCK or SDEV_RUNNING for all devices
* direct attached during device pull.
*/
static void
-_scsih_block_io_to_children_attached_directly(struct MPT3SAS_ADAPTER *ioc,
+_scsih_handle_io_to_children_attached_directly(struct MPT3SAS_ADAPTER *ioc,
Mpi2EventDataSasTopologyChangeList_t *event_data)
{
int i;
u16 handle;
u16 reason_code;
+ struct _sas_device *sas_device;
+ u8 link_rate, prev_link_rate;
for (i = 0; i < event_data->NumEntries; i++) {
handle = le16_to_cpu(event_data->PHY[i].AttachedDevHandle);
@@ -2736,6 +2771,24 @@ _scsih_block_io_to_children_attached_directly(struct MPT3SAS_ADAPTER *ioc,
MPI2_EVENT_SAS_TOPO_RC_MASK;
if (reason_code == MPI2_EVENT_SAS_TOPO_RC_DELAY_NOT_RESPONDING)
_scsih_block_io_device(ioc, handle);
+ else if ((reason_code == MPI2_EVENT_SAS_TOPO_RC_PHY_CHANGED) &&
+ (unblock_io == 1)) {
+ /* unblock only if device is in the process of addition
+ * within the SCSI Mid Layer (sas_rphy_add) to prevent
+ * deadlock. Unblocking in other cases can lead to data
+ * corruption */
+
+ link_rate = event_data->PHY[i].LinkRate >> 4;
+ prev_link_rate = event_data->PHY[i].LinkRate & 0xF;
+ sas_device = _scsih_sas_device_find_by_handle(ioc,
+ handle);
+ if (!sas_device)
+ continue;
+ if ((link_rate > prev_link_rate) &&
+ (sas_device->pend_sas_rphy_add == 1))
+ _scsih_ublock_io_device_to_running(ioc,
+ sas_device->sas_address);
+ }
}
}
@@ -3143,7 +3196,7 @@ _scsih_check_topo_delete_events(struct MPT3SAS_ADAPTER *ioc,
expander_handle = le16_to_cpu(event_data->ExpanderDevHandle);
if (expander_handle < ioc->sas_hba.num_phys) {
- _scsih_block_io_to_children_attached_directly(ioc, event_data);
+ _scsih_handle_io_to_children_attached_directly(ioc, event_data);
return;
}
if (event_data->ExpStatus ==
@@ -3161,7 +3214,7 @@ _scsih_check_topo_delete_events(struct MPT3SAS_ADAPTER *ioc,
_scsih_block_io_device(ioc, handle);
} while (test_and_clear_bit(handle, ioc->blocking_handles));
} else if (event_data->ExpStatus == MPI2_EVENT_SAS_TOPO_ES_RESPONDING)
- _scsih_block_io_to_children_attached_directly(ioc, event_data);
+ _scsih_handle_io_to_children_attached_directly(ioc, event_data);
if (event_data->ExpStatus != MPI2_EVENT_SAS_TOPO_ES_NOT_RESPONDING)
return;
diff --git a/drivers/scsi/mpt3sas/mpt3sas_transport.c b/drivers/scsi/mpt3sas/mpt3sas_transport.c
index efb98af..1695f0f 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_transport.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_transport.c
@@ -649,6 +649,7 @@ mpt3sas_transport_port_add(struct MPT3SAS_ADAPTER *ioc, u16 handle,
unsigned long flags;
struct _sas_node *sas_node;
struct sas_rphy *rphy;
+ struct _sas_device *sas_device = NULL;
int i;
struct sas_port *port;
@@ -731,10 +732,23 @@ mpt3sas_transport_port_add(struct MPT3SAS_ADAPTER *ioc, u16 handle,
mpt3sas_port->remote_identify.device_type);
rphy->identify = mpt3sas_port->remote_identify;
+ if (mpt3sas_port->remote_identify.device_type == SAS_END_DEVICE) {
+ sas_device = mpt3sas_scsih_sas_device_find_by_sas_address(ioc,
+ mpt3sas_port->remote_identify.sas_address);
+ if (!sas_device) {
+ dfailprintk(ioc, printk(MPT3SAS_FMT
+ "failure at %s:%d/%s()!\n",
+ ioc->name, __FILE__, __LINE__, __func__));
+ goto out_fail;
+ }
+ sas_device->pend_sas_rphy_add = 1;
+ }
if ((sas_rphy_add(rphy))) {
pr_err(MPT3SAS_FMT "failure at %s:%d/%s()!\n",
ioc->name, __FILE__, __LINE__, __func__);
}
+ if (mpt3sas_port->remote_identify.device_type == SAS_END_DEVICE)
+ sas_device->pend_sas_rphy_add = 0;
if ((ioc->logging_level & MPT_DEBUG_TRANSPORT))
dev_printk(KERN_INFO, &rphy->dev,
"add: handle(0x%04x), sas_addr(0x%016llx)\n",
--
2.0.2
--
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