John Garry fbefe22811 scsi: libsas: Don't always drain event workqueue for HA resume ... For the hisi_sas driver, if a directly attached disk is removed during suspend, a hang will occur in the resume process: The background is that in commit 16fd4a7c59 ("scsi: hisi_sas: Add device link between SCSI devices and hisi_hba"), it is ensured that the HBA device cannot be runtime suspended when any SCSI device associated is active. Other drivers which use libsas don't worry about this as none support runtime suspend. The mentioned hang occurs when an disk is removed during suspend. In the removal process - from PHYE_RESUME_TIMEOUT event processing - we call into scsi_remove_device(), which is being processed in the HA event workqueue. Here we wait for all suppliers of the SCSI device to resume, which includes the HBA device (from the above commit). However the HBA device cannot resume, as it is waiting for the PHYE_RESUME_TIMEOUT to be processed (from calling sas_resume_ha() -> sas_drain_work()). This is the deadlock. There does not appear to be any need for the sas_drain_work() to be called at all in sas_resume_ha() as it is not syncing against anything, so allow LLDDs to avoid this by providing a variant of sas_resume_ha() which does "sync", i.e. doesn't drain the event workqueue. Link: https://lore.kernel.org/r/1639999298-244569-2-git-send-email-chenxiang66@hisilicon.com Signed-off-by: John Garry <john.garry@huawei.com> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>		2021-12-22 23:38:29 -05:00
..
acpi	Merge branches 'acpica', 'acpi-ec', 'acpi-pmic' and 'acpi-video'	2021-11-10 14:03:14 +01:00
asm-generic	asm-generic: asm/syscall.h cleanup	2021-11-10 11:22:03 -08:00
clocksource	ARM:	2021-11-02 11:24:14 -07:00
crypto	crypto: ecc - Export additional helper functions	2021-10-29 21:04:03 +08:00
drm	Removed the TTM Huge Page functionnality to address a crash, a timeout	2021-11-11 08:14:19 +10:00
dt-bindings	dt-bindings: Rename Ingenic CGU headers to ingenic,*.h	2021-11-11 22:27:14 -06:00
keys
kunit	include/kunit/test.h: replace kernel.h with the necessary inclusions	2021-11-09 10:02:49 -08:00
kvm
linux	A single fix for POSIX CPU timers to address a problem where POSIX CPU	2021-11-14 10:43:38 -08:00
math-emu
media	Merge branch 'akpm' (patches from Andrew)	2021-11-09 10:11:53 -08:00
memory
misc
net	Networking fixes for 5.16-rc1, including fixes from bpf, can	2021-11-11 09:49:36 -08:00
pcmcia
ras
rdma	RDMA/hns: Use the core code to manage the fixed mmap entries	2021-10-29 14:07:31 -03:00
scsi	scsi: libsas: Don't always drain event workqueue for HA resume	2021-12-22 23:38:29 -05:00
soc	ARM: SoC drivers for 5.16	2021-11-03 17:00:52 -07:00
sound	Revert "ALSA: memalloc: Convert x86 SG-buffer handling with non-contiguous type"	2021-11-04 22:10:03 +01:00
target	scsi: target: Replace lun_tg_pt_gp_lock with rcu in I/O path	2021-10-18 22:38:36 -04:00
trace	f2fs-for-5.16-rc1	2021-11-13 11:20:22 -08:00
uapi	virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE	2021-11-13 13:14:05 -08:00
vdso
video
xen	xen/balloon: rename alloc/free_xenballooned_pages	2021-11-04 12:59:44 -05:00