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authorJohn Garry <john.garry@huawei.com>2021-12-20 14:21:24 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2021-12-23 07:38:29 +0300
commitfbefe22811c3140a686e407e114789ebf328a9a2 (patch)
tree75086b929e23c76bd9f950582c387c87a5645757 /include/scsi
parent4be6181fea1dbfd21a8d73f69d87a6cae2d3023d (diff)
downloadlinux-fbefe22811c3140a686e407e114789ebf328a9a2.tar.xz
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 16fd4a7c5917 ("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>
Diffstat (limited to 'include/scsi')
-rw-r--r--include/scsi/libsas.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 79e4903bd414..a795a2d9e5b1 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -660,6 +660,7 @@ 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_set_phy_speed(struct sas_phy *phy, struct sas_phy_linkrates *rates);