From 3dbbbf656b850c9c8de05df6ad4a1dfc6ff02845 Mon Sep 17 00:00:00 2001 From: Xingui Yang Date: Thu, 16 Jul 2026 16:11:45 +0800 Subject: scsi: libsas: Fix HA resume deadlock and hisi_sas disk-wake race Commit fbefe22811c3 ("scsi: libsas: Don't always drain event workqueue for HA resume") introduced sas_resume_ha_no_sync() to avoid a deadlock: the PHYE_RESUME_TIMEOUT handler, running on the HA event workqueue, calls sas_deform_port() -> sas_destruct_devices(), which removes SCSI devices and waits for the host to become runtime-active. But the host cannot resume until sas_resume_ha() -> sas_drain_work() returns, and the drain is blocked on that very handler. However skipping the drain reintroduces a race: hisi_sas returns from resume before all PHY UP work and libsas discovery work finish. The controller may then autosuspend while disks are still waking up. The disks issue IO to a suspended controller, the IO fails, and the disks get disabled. Fix the deadlock at its source by moving the PHYE_RESUME_TIMEOUT notification to after sas_drain_work(). By then the host resume is about to complete, so device removal through device_link no longer blocks on the resume and the cycle is broken. With the deadlock gone, restore sas_resume_ha() (the draining variant) in hisi_sas and remove sas_resume_ha_no_sync(). The reorder is safe for the other libsas consumers (isci, pm8001, aic94xx, mvsas). During suspend, sas_suspend_devices() calls sas_notify_lldd_dev_gone() for each device, which sets dev->lldd_dev to NULL. When scsi_unblock_requests re-enables I/O in resume, any I/O to a timed-out phy's disk is immediately rejected by the LLDD before reaching hardware: isci returns SAS_DEVICE_UNKNOWN (mapped to DID_BAD_TARGET), and pm8001 returns SAS_PHY_DOWN (mapped to DID_NO_CONNECT). Both complete directly via scsi_done() without entering SCSI EH. This is identical in both the old and new ordering since lldd_dev_gone runs during suspend, before resume. The reorder only affects when the PHYE_RESUME_TIMEOUT handler runs (synchronized by sas_drain_work() vs. asynchronous after resume returns), not whether I/O can reach the device. aic94xx and mvsas do not register any PM ops and never reach this code path. Fixes: fbefe22811c3 ("scsi: libsas: Don't always drain event workqueue for HA resume") Signed-off-by: Xingui Yang Reviewed-by: John Garry Link: https://patch.msgid.link/20260716081145.3950172-1-yangxingui@huawei.com Signed-off-by: Martin K. Petersen --- include/scsi/libsas.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/scsi') diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h index 163f23c92b41..36d4cb567837 100644 --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -680,7 +680,6 @@ extern int sas_register_ha(struct sas_ha_struct *); extern int sas_unregister_ha(struct sas_ha_struct *); extern void sas_prep_resume_ha(struct sas_ha_struct *sas_ha); extern void sas_resume_ha(struct sas_ha_struct *sas_ha); -extern void sas_resume_ha_no_sync(struct sas_ha_struct *sas_ha); extern void sas_suspend_ha(struct sas_ha_struct *sas_ha); int sas_phy_reset(struct sas_phy *phy, int hard_reset); -- cgit v1.2.3