linux-kernel - [PATCH v5] scsi: libsas: Fix exp-attached end device cannot be scanned in again after probe failed

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Message-ID: <20240619091742.25465-1-yangxingui@huawei.com>
Date: Wed, 19 Jun 2024 09:17:42 +0000
From: Xingui Yang <yangxingui@...wei.com>
To: <john.g.garry@...cle.com>, <yanaijie@...wei.com>, <jejb@...ux.ibm.com>,
	<martin.petersen@...cle.com>, <damien.lemoal@...nsource.wdc.com>
CC: <linux-scsi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linuxarm@...wei.com>, <prime.zeng@...ilicon.com>,
	<chenxiang66@...ilicon.com>, <kangfenglong@...wei.com>
Subject: [PATCH v5] scsi: libsas: Fix exp-attached end device cannot be scanned in again after probe failed

The expander phy will be treated as broadcast flutter in the next
revalidation after the exp-attached end device probe failed, as follows:

[78779.654026] sas: broadcast received: 0
[78779.654037] sas: REVALIDATING DOMAIN on port 0, pid:10
[78779.654680] sas: ex 500e004aaaaaaa1f phy05 change count has changed
[78779.662977] sas: ex 500e004aaaaaaa1f phy05 originated BROADCAST(CHANGE)
[78779.662986] sas: ex 500e004aaaaaaa1f phy05 new device attached
[78779.663079] sas: ex 500e004aaaaaaa1f phy05:U:8 attached: 500e004aaaaaaa05 (stp)
[78779.693542] hisi_sas_v3_hw 0000:b4:02.0: dev[16:5] found
[78779.701155] sas: done REVALIDATING DOMAIN on port 0, pid:10, res 0x0
[78779.707864] sas: Enter sas_scsi_recover_host busy: 0 failed: 0
...
[78835.161307] sas: --- Exit sas_scsi_recover_host: busy: 0 failed: 0 tries: 1
[78835.171344] sas: sas_probe_sata: for exp-attached device 500e004aaaaaaa05 returned -19
[78835.180879] hisi_sas_v3_hw 0000:b4:02.0: dev[16:5] is gone
[78835.187487] sas: broadcast received: 0
[78835.187504] sas: REVALIDATING DOMAIN on port 0, pid:10
[78835.188263] sas: ex 500e004aaaaaaa1f phy05 change count has changed
[78835.195870] sas: ex 500e004aaaaaaa1f phy05 originated BROADCAST(CHANGE)
[78835.195875] sas: ex 500e004aaaaaaa1f rediscovering phy05
[78835.196022] sas: ex 500e004aaaaaaa1f phy05:U:A attached: 500e004aaaaaaa05 (stp)
[78835.196026] sas: ex 500e004aaaaaaa1f phy05 broadcast flutter
[78835.197615] sas: done REVALIDATING DOMAIN on port 0, pid:10, res 0x0

The cause of the problem is that the related ex_phy's attached_sas_addr was
not cleared after the end device probe failed, so reset it.

Signed-off-by: Xingui Yang <yangxingui@...wei.com>
Reviewed-by: John Garry <john.g.garry@...cle.com>
---
Changes since v4:
- Optimize code and comments based on John's suggestion.

Changes since v3:
- Just manually clear the ex_phy's attached_sas_addr instead of calling
  sas_unregister_devs_sas_addr() and deleting the port.
- Update commit information.

Changes since v2:
- Add a helper for calling sas_destruct_devices() and sas_destruct_ports(),
  and put the new call at the end of sas_probe_devices() based on John's
  suggestion.

Changes since v1:
- Simplify the process of getting ex_phy id based on Jason's suggestion.
- Update commit information.
---
 drivers/scsi/libsas/sas_internal.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 85948963fb97..03d6ec1eb970 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -145,6 +145,20 @@ static inline void sas_fail_probe(struct domain_device *dev, const char *func, i
 		func, dev->parent ? "exp-attached" :
 		"direct-attached",
 		SAS_ADDR(dev->sas_addr), err);
+
+	/*
+	 * If the device probe failed, the expander phy attached address
+	 * needs to be reset so that the phy will not be treated as flutter
+	 * in the next revalidation
+	 */
+	if (dev->parent && !dev_is_expander(dev->dev_type)) {
+		struct sas_phy *phy = dev->phy;
+		struct domain_device *parent = dev->parent;
+		struct ex_phy *ex_phy = &parent->ex_dev.ex_phy[phy->number];
+
+		memset(ex_phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
+	}
+
 	sas_unregister_dev(dev->port, dev);
 }
 
-- 
2.17.1