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scsi: libsas: Add linkrate and sas_addr change detection in rediscover

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Introduce sas_dev_is_flutter() and sas_rediscover_ex_phy() to improve
flutter and device replace detection during rediscovery.

sas_dev_is_flutter() calls sas_ex_phy_discover() before looking up the
child device via sas_ex_phy_to_dev(), ensuring the PHY state is always
updated and avoiding use-after-free since the child device pointer is
obtained after the sleeping SMP request completes.

Add validation for linkrate and sas_addr changes. When the SAS address
changes, phy->attached_sas_addr is restored to the original address
before returning false, so sas_unregister_devs_sas_addr() can properly
match and unregister the old device. The sas_addr check is ordered
before the linkrate check to avoid skipping the restoration when both
change simultaneously.

sas_rediscover_ex_phy() uses the async discovery pattern
(sas_discover_event) instead of the synchronous sas_discover_new() to
ensure proper ordering between device unregistration and rediscovery,
avoiding sysfs_warn_dup() errors.

Signed-off-by: Xingui Yang <yangxingui@huawei.com>
Suggested-by: John Garry <john.g.garry@oracle.com>
Link: https://patch.msgid.link/20260811040334.4184911-3-yangxingui@huawei.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>
This commit is contained in:
Xingui Yang 2026-08-11 12:03:34 +08:00 committed by Martin K. Petersen (Oracle)
parent 4c2128c1a3
commit db441dcb8c
1 changed files with 70 additions and 15 deletions
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85
drivers/scsi/libsas/sas_expander.c
View File

@ -1963,6 +1963,72 @@ static bool dev_type_flutter(enum sas_device_type new, enum sas_device_type old)
return false;
}
static void sas_rediscover_ex_phy(struct domain_device *dev, int phy_id,
bool last)
{
struct expander_device *ex = &dev->ex_dev;
struct ex_phy *phy = &ex->ex_phy[phy_id];
phy->phy_change_count = -1;
ex->ex_change_count = -1;
sas_unregister_devs_sas_addr(dev, phy_id, last);
sas_discover_event(dev->port, DISCE_REVALIDATE_DOMAIN);
}
static bool sas_dev_is_flutter(struct domain_device *dev, int phy_id,
u8 *sas_addr, enum sas_device_type type)
{
struct expander_device *ex = &dev->ex_dev;
struct ex_phy *phy = &ex->ex_phy[phy_id];
struct domain_device *child_dev;
char *action = "";
int res;
if (SAS_ADDR(sas_addr) != SAS_ADDR(phy->attached_sas_addr) ||
!dev_type_flutter(type, phy->attached_dev_type))
return false;
res = sas_ex_phy_discover(dev, phy_id);
if (res)
return false;
child_dev = sas_ex_phy_to_dev(dev, phy_id);
if (!child_dev)
goto out;
if (dev_is_sata(child_dev) &&
phy->attached_dev_type == SAS_SATA_PENDING) {
action = ", needs recovery";
goto out;
}
if (SAS_ADDR(child_dev->sas_addr) != SAS_ADDR(phy->attached_sas_addr)) {
pr_info("ex %016llx phy%02d sas_addr changed from %016llx to %016llx\n",
SAS_ADDR(dev->sas_addr), phy_id,
SAS_ADDR(child_dev->sas_addr),
SAS_ADDR(phy->attached_sas_addr));
/*
* Device unregistering relies on address matching. Restore
* attached_sas_addr back to the original address so that the old
* device can be unregistered later
*/
memcpy(phy->attached_sas_addr, child_dev->sas_addr, SAS_ADDR_SIZE);
return false;
}
if (child_dev->linkrate != phy->linkrate) {
pr_info("ex %016llx phy%02d linkrate changed from %d to %d\n",
SAS_ADDR(dev->sas_addr), phy_id,
child_dev->linkrate, phy->linkrate);
return false;
}
out:
pr_debug("ex %016llx phy%02d broadcast flutter%s\n",
SAS_ADDR(dev->sas_addr), phy_id, action);
return true;
}
static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
bool last, int sibling)
{
@ -2016,27 +2082,16 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
if (res == 0)
sas_set_ex_phy(dev, phy_id, disc_resp);
goto out_free_resp;
} else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) &&
dev_type_flutter(type, phy->attached_dev_type)) {
struct domain_device *ata_dev = sas_ex_to_ata(dev, phy_id);
char *action = "";
sas_ex_phy_discover(dev, phy_id);
if (ata_dev && phy->attached_dev_type == SAS_SATA_PENDING)
action = ", needs recovery";
pr_debug("ex %016llx phy%02d broadcast flutter%s\n",
SAS_ADDR(dev->sas_addr), phy_id, action);
goto out_free_resp;
}
if (sas_dev_is_flutter(dev, phy_id, sas_addr, type))
goto out_free_resp;
/* we always have to delete the old device when we went here */
pr_info("ex %016llx phy%02d replace %016llx\n",
SAS_ADDR(dev->sas_addr), phy_id,
SAS_ADDR(phy->attached_sas_addr));
sas_unregister_devs_sas_addr(dev, phy_id, last);
res = sas_discover_new(dev, phy_id);
sas_rediscover_ex_phy(dev, phy_id, last);
out_free_resp:
kfree(disc_resp);
return res;