Messages in this thread | | | Subject | Re: [PATCH v2 4/7] scsi: libsas: split the replacement of sas disks in two steps | From | John Garry <> | Date | Thu, 31 Jan 2019 10:29:17 +0000 |
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On 31/01/2019 02:04, Jason Yan wrote: > > > On 2019/1/31 1:22, John Garry wrote: >> On 30/01/2019 08:24, Jason Yan wrote: >>> Now if a new device replaced a old device, the sas address will change. >> >> Hmmm... not if it's a SATA disk, which would have some same invented SAS >> address. >> > > Yes, it's only for a SAS disk. > >>> We unregister the old device and discover the new device in one >>> revalidation process. But after we deferred the sas_port_delete(), the >>> sas port is not deleted when we registering the new port and device. >>> The sas port cannot be added because the name of the new port is the >>> same as the old. >>> >>> Fix this by doing the replacement in two steps. The first revalidation >>> only delete the old device and trigger a new revalidation. The second >>> revalidation discover the new device. To keep the event processing >>> synchronised to the original event, >> >> Did I originally suggest this? It seems to needlessly make the code more >> complicated. >> > > Yes, my first version was raise a new bcast event, and you said it's not > synchronised to the original event. Shall I get back to that approach?
Not sure. This patch seems to fix something closely related to that in "scsi: libsas: fix issue of swapping two sas disks", which I will check further.
EOM
> >> we wrapped a loop and added a new >>> parameter to see if we should revalidate again. >>> >>> Signed-off-by: Jason Yan <yanaijie@huawei.com> >>> CC: chenxiang <chenxiang66@hisilicon.com> >>> CC: John Garry <john.garry@huawei.com> >>> CC: Johannes Thumshirn <jthumshirn@suse.de> >>> CC: Ewan Milne <emilne@redhat.com> >>> CC: Christoph Hellwig <hch@lst.de> >>> CC: Tomas Henzl <thenzl@redhat.com> >>> CC: Dan Williams <dan.j.williams@intel.com> >>> CC: Hannes Reinecke <hare@suse.com> >>> --- >>> drivers/scsi/libsas/sas_discover.c | 20 +++++++++++++++----- >>> drivers/scsi/libsas/sas_expander.c | 20 ++++++++++++++------ >>> include/scsi/libsas.h | 2 +- >>> 3 files changed, 30 insertions(+), 12 deletions(-) >>> >>> diff --git a/drivers/scsi/libsas/sas_discover.c >>> b/drivers/scsi/libsas/sas_discover.c >>> index ffc571a12916..c825c89fbddd 100644 >>> --- a/drivers/scsi/libsas/sas_discover.c >>> +++ b/drivers/scsi/libsas/sas_discover.c >>> @@ -498,12 +498,10 @@ static void sas_discover_domain(struct >>> work_struct *work) >>> task_pid_nr(current), error); >>> } >>> >>> -static void sas_revalidate_domain(struct work_struct *work) >>> +static void sas_do_revalidate_domain(struct asd_sas_port *port, bool >>> *retry) >>> { >>> - struct sas_discovery_event *ev = to_sas_discovery_event(work); >>> - struct asd_sas_port *port = ev->port; >>> - struct sas_ha_struct *ha = port->ha; >>> struct domain_device *ddev = port->port_dev; >>> + struct sas_ha_struct *ha = port->ha; >>> >>> /* prevent revalidation from finding sata links in recovery */ >>> mutex_lock(&ha->disco_mutex); >>> @@ -520,7 +518,7 @@ static void sas_revalidate_domain(struct >>> work_struct *work) >>> >>> if (ddev && (ddev->dev_type == SAS_FANOUT_EXPANDER_DEVICE || >>> ddev->dev_type == SAS_EDGE_EXPANDER_DEVICE)) >>> - sas_ex_revalidate_domain(ddev); >>> + sas_ex_revalidate_domain(ddev, retry); >>> >>> pr_debug("done REVALIDATING DOMAIN on port %d, pid:%d\n", >>> port->id, task_pid_nr(current)); >>> @@ -532,6 +530,18 @@ static void sas_revalidate_domain(struct >>> work_struct *work) >>> sas_probe_devices(port); >>> } >>> >>> +static void sas_revalidate_domain(struct work_struct *work) >>> +{ >>> + struct sas_discovery_event *ev = to_sas_discovery_event(work); >>> + struct asd_sas_port *port = ev->port; >>> + bool retry; >>> + >>> + do { >>> + retry = false; >>> + sas_do_revalidate_domain(port, &retry); >>> + } while (retry); >>> +} >>> + >>> /* ---------- Events ---------- */ >>> >>> static void sas_chain_work(struct sas_ha_struct *ha, struct sas_work >>> *sw) >>> diff --git a/drivers/scsi/libsas/sas_expander.c >>> b/drivers/scsi/libsas/sas_expander.c >>> index 5cd720f93f96..cdbf8d8a28bf 100644 >>> --- a/drivers/scsi/libsas/sas_expander.c >>> +++ b/drivers/scsi/libsas/sas_expander.c >>> @@ -1994,7 +1994,8 @@ static bool dev_type_flutter(enum >>> sas_device_type new, enum sas_device_type old) >>> return false; >>> } >>> >>> -static int sas_rediscover_dev(struct domain_device *dev, int phy_id, >>> bool last) >>> +static int sas_unregister(struct domain_device *dev, int phy_id, bool >>> last, >>> + bool *retry) >>> { >>> struct expander_device *ex = &dev->ex_dev; >>> struct ex_phy *phy = &ex->ex_phy[phy_id]; >>> @@ -2045,7 +2046,12 @@ static int sas_rediscover_dev(struct >>> domain_device *dev, int phy_id, bool last) >>> SAS_ADDR(phy->attached_sas_addr)); >>> sas_unregister_devs_sas_addr(dev, phy_id, last); >>> >>> - return sas_discover_new(dev, phy_id); >>> + /* force the next revalidation find this phy and bring it up */ >>> + phy->phy_change_count = -1; >>> + ex->ex_change_count = -1; >>> + *retry = true; >> >> Ohh, sorry to say, but that's a real hack :) >> > > This is the way sas_resume_port() already in use. > >> Could we just add a flag for the expander PHY to force a discovery >> instead of this? >> > > of course we can add a flag instead of this, but I don't think it worth > to do this. We have to change the logic of sas_find_bcast_dev() and > sas_find_bcast_phy() to achieve this. Or we have to add a new function > to find out which PHY's flag is set. > >> I assume that you need to do this as the expander PHY change count will >> not be modified for the next revalidation (so no discovery on that PHY). >> > > To save one instruction(assign), we have to add two(check and assign)? > And how to predict if the PHY change count will be modified or not? > It's unnessesary to do this. > >>> + >>> + return 0; >>> } >>> >>> /** >>> @@ -2062,7 +2068,8 @@ static int sas_rediscover_dev(struct >>> domain_device *dev, int phy_id, bool last) >>> * first phy,for other phys in this port, we add it to the port to >>> * forming the wide-port. >>> */ >>> -static void sas_rediscover(struct domain_device *dev, const int phy_id) >>> +static void sas_rediscover(struct domain_device *dev, const int phy_id, >>> + bool *retry) >>> { >>> struct expander_device *ex = &dev->ex_dev; >>> struct ex_phy *changed_phy = &ex->ex_phy[phy_id]; >>> @@ -2087,7 +2094,7 @@ static void sas_rediscover(struct domain_device >>> *dev, const int phy_id) >>> break; >>> } >>> } >>> - res = sas_rediscover_dev(dev, phy_id, last); >>> + res = sas_unregister(dev, phy_id, last, retry); >>> } else >>> res = sas_discover_new(dev, phy_id); >>> >>> @@ -2098,13 +2105,14 @@ static void sas_rediscover(struct >>> domain_device *dev, const int phy_id) >>> /** >>> * sas_ex_revalidate_domain - revalidate the domain >>> * @port_dev: port domain device. >>> + * @retry: do we need to revalidate again >>> * >>> * NOTE: this process _must_ quit (return) as soon as any connection >>> * errors are encountered. Connection recovery is done elsewhere. >>> * Discover process only interrogates devices in order to discover the >>> * domain. >>> */ >>> -void sas_ex_revalidate_domain(struct domain_device *port_dev) >>> +void sas_ex_revalidate_domain(struct domain_device *port_dev, bool >>> *retry) >>> { >>> int res; >>> struct domain_device *dev = NULL; >>> @@ -2119,7 +2127,7 @@ void sas_ex_revalidate_domain(struct >>> domain_device *port_dev) >>> res = sas_find_bcast_phy(dev, &phy_id, i, true); >>> if (phy_id == -1) >>> break; >>> - sas_rediscover(dev, phy_id); >>> + sas_rediscover(dev, phy_id, retry); >>> i = phy_id + 1; >>> } while (i < ex->num_phys); >>> } >>> diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h >>> index e557bcb0c266..deb75765e555 100644 >>> --- a/include/scsi/libsas.h >>> +++ b/include/scsi/libsas.h >>> @@ -692,7 +692,7 @@ int sas_discover_root_expander(struct >>> domain_device *); >>> >>> void sas_init_ex_attr(void); >>> >>> -void sas_ex_revalidate_domain(struct domain_device *); >>> +void sas_ex_revalidate_domain(struct domain_device *port_dev, bool >>> *retry); >>> >>> void sas_unregister_domain_devices(struct asd_sas_port *port, int >>> gone); >>> void sas_init_disc(struct sas_discovery *disc, struct asd_sas_port *); >>> >> >> >> >> . >> > > > . >
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