From: Don Brace don.brace@microsemi.com
[ Upstream commit 3e16e83a62edac7617bfd8dbb4e55d04ff6adbe1 ]
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@brunh... 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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/hpsa.c | 80 ++++++++++++++++++++++++++++++++------------- 1 file changed, 57 insertions(+), 23 deletions(-)
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c index 216e557f703e6..e67cb4561aace 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);