Re: [PATCH v4 00/11] Enhance libsas hotplug feature

From: John Garry
Date: Mon Sep 18 2017 - 08:55:18 EST

On 06/09/2017 10:15, Jason Yan wrote:
Hello all, Yijing Wang handed over this topic to me. We are working
on it the last two months. We have tested the patchset for a long
time. Here is the new version.

Now the libsas hotplug has some issues, Dan Williams report
a similar bug here before

The issues we have found
1. if LLDD burst reports lots of phy-up/phy-down sas events, some events
may lost because a same sas events is pending now, finally libsas topo
may different the hardware.
2. receive a phy down sas event, libsas call sas_deform_port to remove
devices, it would first delete the sas port, then put a destruction
discovery event in a new work, and queue it at the tail of workqueue,
once the sas port be deleted, its children device will be deleted too,
when the destruction work start, it will found the target device has
been removed, and report a sysfs warnning.
3. since a hotplug process will be divided into several works, if a phy up
sas event insert into phydown works, like
destruction work ---> PORTE_BYTES_DMAED (sas_form_port) ---->PHYE_LOSS_OF_SIGNAL
the hot remove flow would broken by PORTE_BYTES_DMAED event, it's not
we expected, and issues would occur.

I have tried to verify PM suspend/resume feature with this patchset to ensure that it is not broken.

Since our hisi_sas driver does not support PM yet, I have got my hands on an adaptec card which uses pm8001 driver (it's vendor 9065, device 8088) to test.

So in the PM resume, sometimes I find the console locks up with and without this patchset. In these cases, I find this log:
[ 59.344266] pm80xx pm80xx_chip_init 1098:Firmware is not ready!

Is this a known issue? Should we have a chip reset in all cases in the resume code, marked ***:
static int pm8001_pci_resume(struct pci_dev *pdev)

rc = pci_go_44(pdev);
if (rc)
goto err_out_disable;

/* chip soft rst only for spc */
if (pm8001_ha->chip_id == chip_8001) { **** HERE
pm8001_printk("chip soft reset successful\n"));
rc = PM8001_CHIP_DISP->chip_init(pm8001_ha);
if (rc)
goto err_out_disable;



v3->v4: -get rid of unused ha event and do some cleanup
-use dynamic alloced work and support shutting down the phy if active event reached the threshold
-use flush_workqueue instead of wait-completion to process discover events synchronously
-direct call probe and destruct function
-other small code improvements
v2->v3: some code improvements suggested by Johannes and John,
split v2 patch 2 into several small patches.
v1->v2: some code improvements suggested by John Garry

Jason Yan (10):
libsas: kill useless ha_event and do some cleanup
libsas: remove the numbering for each event enum
libsas: remove unused port_gone_completion and DISCE_PORT_GONE
libsas: rename notify_port_event() for consistency
libsas: Use dynamic alloced work to avoid sas event lost
libsas: shut down the PHY if events reached the threshold
libsas: make the event threshold configurable
libsas: Use new workqueue to run sas event and disco event
libsas: libsas: use flush_workqueue to process disco events
libsas: direct call probe and destruct

chenxiang (1):
libsas: add event to defer list tail instead of head when draining

drivers/scsi/aic94xx/aic94xx_hwi.c | 3 -
drivers/scsi/hisi_sas/hisi_sas_main.c | 7 ++-
drivers/scsi/libsas/sas_ata.c | 1 -
drivers/scsi/libsas/sas_discover.c | 36 +++++++-----
drivers/scsi/libsas/sas_dump.c | 10 ----
drivers/scsi/libsas/sas_dump.h | 1 -
drivers/scsi/libsas/sas_event.c | 97 +++++++++++++++++++-------------
drivers/scsi/libsas/sas_expander.c | 2 +-
drivers/scsi/libsas/sas_init.c | 101 +++++++++++++++++++++++++++++-----
drivers/scsi/libsas/sas_internal.h | 7 +++
drivers/scsi/libsas/sas_phy.c | 73 ++++++++++++------------
drivers/scsi/libsas/sas_port.c | 25 +++++----
include/scsi/libsas.h | 81 ++++++++++++---------------
include/scsi/scsi_transport_sas.h | 1 +
14 files changed, 270 insertions(+), 175 deletions(-)