[PATCH 1/3] libsas: flush initial device discovery before completing ->scan_finished()
From: Dan Williams <hidden>
Date: 2011-05-03 18:36:22
Also in:
linux-scsi
Subsystem:
pmc sierra pm8001 driver, scsi libsas subsystem, scsi subsystem, the rest · Maintainers:
Jack Wang, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
During initial scan libsas drivers start their phys and notify libsas with PORTE_BYTES_DMAED events as port links are established. This notification in turn causes libsas to post DISCE_DISCOVER_DOMAIN events to the queue. Calling scsi_flush_work() at the end of scan_finished guarantees that all preceding PORTE_BYTES_DMAED events have been registered in the queue, but it does not guarantee that the resulting DISCE_DISCOVER_DOMAIN events have been processed because flush_workqueue() explicitly avoids live-locking with incoming work. Introduce sas_flush_discovery() to guarantee that all initial discovery events have completed. It is called after the driver determines all initial PORTE_BYTES_DMAED events have had a chance to enter the queue. This does not cover BCNs that are generated during expander bring up, only the initial sas_discover_domain() event. Cc: David Milburn <redacted> Cc: Srinivas <redacted> Cc: jack_wang@usish.com Cc: lindar_liu@usish.com Signed-off-by: Dan Williams <redacted> --- drivers/scsi/aic94xx/aic94xx_init.c | 2 +- drivers/scsi/mvsas/mv_sas.c | 2 +- drivers/scsi/pm8001/pm8001_sas.c | 2 +- include/scsi/libsas.h | 13 +++++++++++++ 4 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/aic94xx/aic94xx_init.c b/drivers/scsi/aic94xx/aic94xx_init.c
index 3b7e83d..f763daa 100644
--- a/drivers/scsi/aic94xx/aic94xx_init.c
+++ b/drivers/scsi/aic94xx/aic94xx_init.c@@ -972,7 +972,7 @@ static int asd_scan_finished(struct Scsi_Host *shost, unsigned long time) if (time < HZ) return 0; /* Wait for discovery to finish */ - scsi_flush_work(shost); + sas_flush_discovery(shost); return 1; }
diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c
index adedaa9..e34c378 100644
--- a/drivers/scsi/mvsas/mv_sas.c
+++ b/drivers/scsi/mvsas/mv_sas.c@@ -440,7 +440,7 @@ int mvs_scan_finished(struct Scsi_Host *shost, unsigned long time) if (time < HZ) return 0; /* Wait for discovery to finish */ - scsi_flush_work(shost); + sas_flush_discovery(shost); return 1; }
diff --git a/drivers/scsi/pm8001/pm8001_sas.c b/drivers/scsi/pm8001/pm8001_sas.c
index 6ae059e..997cf59 100644
--- a/drivers/scsi/pm8001/pm8001_sas.c
+++ b/drivers/scsi/pm8001/pm8001_sas.c@@ -253,7 +253,7 @@ int pm8001_scan_finished(struct Scsi_Host *shost, unsigned long time) if (time < HZ) return 0; /* Wait for discovery to finish */ - scsi_flush_work(shost); + sas_flush_discovery(shost); return 1; }
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 5173bba..d4ada3b 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h@@ -405,6 +405,19 @@ static inline void sas_phy_disconnected(struct asd_sas_phy *phy) phy->linkrate = SAS_LINK_RATE_UNKNOWN; } +/* Before returning from ->scan_finished() an LLDD calls this routine to + * ensure that all port notifications have been promoted to domain + * discovery events, and that initial domain discovery has completed + */ +static inline void sas_flush_discovery(struct Scsi_Host *shost) +{ + /* flush port events */ + scsi_flush_work(shost); + + /* flush domain discovery events queued by the port events */ + scsi_flush_work(shost); +} + /* ---------- Tasks ---------- */ /* service_response | SAS_TASK_COMPLETE | SAS_TASK_UNDELIVERED |