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authorDon Brace <don.brace@microsemi.com>2020-03-20 13:26:18 -0500
committerMartin K. Petersen <martin.petersen@oracle.com>2020-03-26 22:44:41 -0400
commit3e16e83a62edac7617bfd8dbb4e55d04ff6adbe1 (patch)
treeb321ff0f87649c5e9b0a6f82067807248dda8327 /drivers/scsi
parentfd6282af8ebd92a32d0b877efb28a3f3272fbed0 (diff)
scsi: hpsa: correct race condition in offload enabled
Correct race condition where ioaccel is re-enabled before the raid_map is updated. For RAID_1, RAID_1ADM, and RAID 5/6 there is a BUG_ON called which is bad. - Change event thread to disable ioaccel only. Send all requests down the RAID path instead. - Have rescan thread handle offload_enable. - Since there is only one rescan allowed at a time, turning offload_enabled on/off should not be racy. Each handler queues up a rescan if one is already in progress. - For timing diagram, offload_enabled is initially off due to a change (transformation: splitmirror/remirror), ... otbe = offload_to_be_enabled oe = offload_enabled Time Event Rescan Completion Request Worker Worker Thread Thread ---- ------ ------ ---------- ------- T0 | | + UA | T1 | + rescan started | 0x3f | T2 + Event | | 0x0e | T3 + Ack msg | | | T4 | + if (!dev[i]->oe && | | T5 | | dev[i]->otbe) | | T6 | | get_raid_map | | T7 + otbe = 1 | | | T8 | | | | T9 | + oe = otbe | | T10 | | | + ioaccel request T11 * BUG_ON T0 - I/O completion with UA 0x3f 0x0e sets rescan flag. T1 - rescan worker thread starts a rescan. T2 - event comes in T3 - event thread starts and issues "Acknowledge" message ... T6 - rescan thread has bypassed code to reload new raid map. ... T7 - event thread runs and sets offload_to_be_enabled ... T9 - rescan thread turns on offload_enabled. T10- request comes in and goes down ioaccel path. T11- BUG_ON. - After the patch is applied, ioaccel_enabled can only be re-enabled in the re-scan thread. Link: https://lore.kernel.org/r/158472877894.14200.7077843399036368335.stgit@brunhilda Reviewed-by: Scott Teel <scott.teel@microsemi.com> Reviewed-by: Matt Perricone <matt.perricone@microsemi.com> Reviewed-by: Scott Benesh <scott.benesh@microsemi.com> Signed-off-by: Don Brace <don.brace@microsemi.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/hpsa.c80
1 files changed, 57 insertions, 23 deletions
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 1a4ddfacb458..1e9302e99d05 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -504,6 +504,12 @@ static ssize_t host_store_rescan(struct device *dev,
return count;
}
+static void hpsa_turn_off_ioaccel_for_device(struct hpsa_scsi_dev_t *device)
+{
+ device->offload_enabled = 0;
+ device->offload_to_be_enabled = 0;
+}
+
static ssize_t host_show_firmware_revision(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1738,8 +1744,7 @@ static void hpsa_figure_phys_disk_ptrs(struct ctlr_info *h,
__func__,
h->scsi_host->host_no, logical_drive->bus,
logical_drive->target, logical_drive->lun);
- logical_drive->offload_enabled = 0;
- logical_drive->offload_to_be_enabled = 0;
+ hpsa_turn_off_ioaccel_for_device(logical_drive);
logical_drive->queue_depth = 8;
}
}
@@ -2499,8 +2504,7 @@ static void process_ioaccel2_completion(struct ctlr_info *h,
IOACCEL2_SERV_RESPONSE_FAILURE) {
if (c2->error_data.status ==
IOACCEL2_STATUS_SR_IOACCEL_DISABLED) {
- dev->offload_enabled = 0;
- dev->offload_to_be_enabled = 0;
+ hpsa_turn_off_ioaccel_for_device(dev);
}
if (dev->in_reset) {
@@ -3670,10 +3674,17 @@ static void hpsa_get_ioaccel_status(struct ctlr_info *h,
this_device->offload_config =
!!(ioaccel_status & OFFLOAD_CONFIGURED_BIT);
if (this_device->offload_config) {
- this_device->offload_to_be_enabled =
+ bool offload_enabled =
!!(ioaccel_status & OFFLOAD_ENABLED_BIT);
- if (hpsa_get_raid_map(h, scsi3addr, this_device))
- this_device->offload_to_be_enabled = 0;
+ /*
+ * Check to see if offload can be enabled.
+ */
+ if (offload_enabled) {
+ rc = hpsa_get_raid_map(h, scsi3addr, this_device);
+ if (rc) /* could not load raid_map */
+ goto out;
+ this_device->offload_to_be_enabled = 1;
+ }
}
out:
@@ -3996,8 +4007,7 @@ static int hpsa_update_device_info(struct ctlr_info *h,
} else {
this_device->raid_level = RAID_UNKNOWN;
this_device->offload_config = 0;
- this_device->offload_enabled = 0;
- this_device->offload_to_be_enabled = 0;
+ hpsa_turn_off_ioaccel_for_device(this_device);
this_device->hba_ioaccel_enabled = 0;
this_device->volume_offline = 0;
this_device->queue_depth = h->nr_cmds;
@@ -5230,8 +5240,12 @@ static int hpsa_scsi_ioaccel_raid_map(struct ctlr_info *h,
/* Handles load balance across RAID 1 members.
* (2-drive R1 and R10 with even # of drives.)
* Appropriate for SSDs, not optimal for HDDs
+ * Ensure we have the correct raid_map.
*/
- BUG_ON(le16_to_cpu(map->layout_map_count) != 2);
+ if (le16_to_cpu(map->layout_map_count) != 2) {
+ hpsa_turn_off_ioaccel_for_device(dev);
+ return IO_ACCEL_INELIGIBLE;
+ }
if (dev->offload_to_mirror)
map_index += le16_to_cpu(map->data_disks_per_row);
dev->offload_to_mirror = !dev->offload_to_mirror;
@@ -5239,8 +5253,12 @@ static int hpsa_scsi_ioaccel_raid_map(struct ctlr_info *h,
case HPSA_RAID_ADM:
/* Handles N-way mirrors (R1-ADM)
* and R10 with # of drives divisible by 3.)
+ * Ensure we have the correct raid_map.
*/
- BUG_ON(le16_to_cpu(map->layout_map_count) != 3);
+ if (le16_to_cpu(map->layout_map_count) != 3) {
+ hpsa_turn_off_ioaccel_for_device(dev);
+ return IO_ACCEL_INELIGIBLE;
+ }
offload_to_mirror = dev->offload_to_mirror;
raid_map_helper(map, offload_to_mirror,
@@ -5265,7 +5283,10 @@ static int hpsa_scsi_ioaccel_raid_map(struct ctlr_info *h,
r5or6_blocks_per_row =
le16_to_cpu(map->strip_size) *
le16_to_cpu(map->data_disks_per_row);
- BUG_ON(r5or6_blocks_per_row == 0);
+ if (r5or6_blocks_per_row == 0) {
+ hpsa_turn_off_ioaccel_for_device(dev);
+ return IO_ACCEL_INELIGIBLE;
+ }
stripesize = r5or6_blocks_per_row *
le16_to_cpu(map->layout_map_count);
#if BITS_PER_LONG == 32
@@ -8285,7 +8306,7 @@ static int detect_controller_lockup(struct ctlr_info *h)
*
* Called from monitor controller worker (hpsa_event_monitor_worker)
*
- * A Volume (or Volumes that comprise an Array set may be undergoing a
+ * A Volume (or Volumes that comprise an Array set) may be undergoing a
* transformation, so we will be turning off ioaccel for all volumes that
* make up the Array.
*/
@@ -8308,6 +8329,9 @@ static void hpsa_set_ioaccel_status(struct ctlr_info *h)
* Run through current device list used during I/O requests.
*/
for (i = 0; i < h->ndevices; i++) {
+ int offload_to_be_enabled = 0;
+ int offload_config = 0;
+
device = h->dev[i];
if (!device)
@@ -8325,25 +8349,35 @@ static void hpsa_set_ioaccel_status(struct ctlr_info *h)
continue;
ioaccel_status = buf[IOACCEL_STATUS_BYTE];
- device->offload_config =
+
+ /*
+ * Check if offload is still configured on
+ */
+ offload_config =
!!(ioaccel_status & OFFLOAD_CONFIGURED_BIT);
- if (device->offload_config)
- device->offload_to_be_enabled =
+ /*
+ * If offload is configured on, check to see if ioaccel
+ * needs to be enabled.
+ */
+ if (offload_config)
+ offload_to_be_enabled =
!!(ioaccel_status & OFFLOAD_ENABLED_BIT);
/*
+ * If ioaccel is to be re-enabled, re-enable later during the
+ * scan operation so the driver can get a fresh raidmap
+ * before turning ioaccel back on.
+ */
+ if (offload_to_be_enabled)
+ continue;
+
+ /*
* Immediately turn off ioaccel for any volume the
* controller tells us to. Some of the reasons could be:
* transformation - change to the LVs of an Array.
* degraded volume - component failure
- *
- * If ioaccel is to be re-enabled, re-enable later during the
- * scan operation so the driver can get a fresh raidmap
- * before turning ioaccel back on.
- *
*/
- if (!device->offload_to_be_enabled)
- device->offload_enabled = 0;
+ hpsa_turn_off_ioaccel_for_device(device);
}
kfree(buf);