3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: Jason Yan yanaijie@huawei.com
commit 0558f33c06bb910e2879e355192227a8e8f0219d upstream.
In commit 87c8331fcf72 ("[SCSI] libsas: prevent domain rediscovery competing with ata error handling") introduced disco mutex to prevent rediscovery competing with ata error handling and put the whole revalidation in the mutex. But the rphy add/remove needs to wait for the error handling which also grabs the disco mutex. This may leads to dead lock.So the probe and destruct event were introduce to do the rphy add/remove asynchronously and out of the lock.
The asynchronously processed workers makes the whole discovery process not atomic, the other events may interrupt the process. For example, if a loss of signal event inserted before the probe event, the sas_deform_port() is called and the port will be deleted.
And sas_port_delete() may run before the destruct event, but the port-x:x is the top parent of end device or expander. This leads to a kernel WARNING such as:
[ 82.042979] sysfs group 'power' not found for kobject 'phy-1:0:22' [ 82.042983] ------------[ cut here ]------------ [ 82.042986] WARNING: CPU: 54 PID: 1714 at fs/sysfs/group.c:237 sysfs_remove_group+0x94/0xa0 [ 82.043059] Call trace: [ 82.043082] [<ffff0000082e7624>] sysfs_remove_group+0x94/0xa0 [ 82.043085] [<ffff00000864e320>] dpm_sysfs_remove+0x60/0x70 [ 82.043086] [<ffff00000863ee10>] device_del+0x138/0x308 [ 82.043089] [<ffff00000869a2d0>] sas_phy_delete+0x38/0x60 [ 82.043091] [<ffff00000869a86c>] do_sas_phy_delete+0x6c/0x80 [ 82.043093] [<ffff00000863dc20>] device_for_each_child+0x58/0xa0 [ 82.043095] [<ffff000008696f80>] sas_remove_children+0x40/0x50 [ 82.043100] [<ffff00000869d1bc>] sas_destruct_devices+0x64/0xa0 [ 82.043102] [<ffff0000080e93bc>] process_one_work+0x1fc/0x4b0 [ 82.043104] [<ffff0000080e96c0>] worker_thread+0x50/0x490 [ 82.043105] [<ffff0000080f0364>] kthread+0xfc/0x128 [ 82.043107] [<ffff0000080836c0>] ret_from_fork+0x10/0x50
Make probe and destruct a direct call in the disco and revalidate function, but put them outside the lock. The whole discovery or revalidate won't be interrupted by other events. And the DISCE_PROBE and DISCE_DESTRUCT event are deleted as a result of the direct call.
Introduce a new list to destruct the sas_port and put the port delete after the destruct. This makes sure the right order of destroying the sysfs kobject and fix the warning above.
In sas_ex_revalidate_domain() have a loop to find all broadcasted device, and sometimes we have a chance to find the same expander twice. Because the sas_port will be deleted at the end of the whole revalidate process, sas_port with the same name cannot be added before this. Otherwise the sysfs will complain of creating duplicate filename. Since the LLDD will send broadcast for every device change, we can only process one expander's revalidation.
[mkp: kbuild test robot warning]
Signed-off-by: Jason Yan yanaijie@huawei.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 Reviewed-by: Hannes Reinecke hare@suse.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/scsi/libsas/sas_ata.c | 1 - drivers/scsi/libsas/sas_discover.c | 32 +++++++++++++++++------------- drivers/scsi/libsas/sas_expander.c | 8 +++----- drivers/scsi/libsas/sas_internal.h | 1 + drivers/scsi/libsas/sas_port.c | 3 +++ include/scsi/libsas.h | 3 +-- include/scsi/scsi_transport_sas.h | 1 + 7 files changed, 27 insertions(+), 22 deletions(-)
--- a/drivers/scsi/libsas/sas_ata.c +++ b/drivers/scsi/libsas/sas_ata.c @@ -782,7 +782,6 @@ int sas_discover_sata(struct domain_devi if (res) return res;
- sas_discover_event(dev->port, DISCE_PROBE); return 0; }
--- a/drivers/scsi/libsas/sas_discover.c +++ b/drivers/scsi/libsas/sas_discover.c @@ -212,13 +212,9 @@ void sas_notify_lldd_dev_gone(struct dom } }
-static void sas_probe_devices(struct work_struct *work) +static void sas_probe_devices(struct asd_sas_port *port) { struct domain_device *dev, *n; - struct sas_discovery_event *ev = to_sas_discovery_event(work); - struct asd_sas_port *port = ev->port; - - clear_bit(DISCE_PROBE, &port->disc.pending);
/* devices must be domain members before link recovery and probe */ list_for_each_entry(dev, &port->disco_list, disco_list_node) { @@ -294,7 +290,6 @@ int sas_discover_end_dev(struct domain_d res = sas_notify_lldd_dev_found(dev); if (res) return res; - sas_discover_event(dev->port, DISCE_PROBE);
return 0; } @@ -353,13 +348,9 @@ static void sas_unregister_common_dev(st sas_put_device(dev); }
-static void sas_destruct_devices(struct work_struct *work) +void sas_destruct_devices(struct asd_sas_port *port) { struct domain_device *dev, *n; - struct sas_discovery_event *ev = to_sas_discovery_event(work); - struct asd_sas_port *port = ev->port; - - clear_bit(DISCE_DESTRUCT, &port->disc.pending);
list_for_each_entry_safe(dev, n, &port->destroy_list, disco_list_node) { list_del_init(&dev->disco_list_node); @@ -370,6 +361,16 @@ static void sas_destruct_devices(struct } }
+static void sas_destruct_ports(struct asd_sas_port *port) +{ + struct sas_port *sas_port, *p; + + list_for_each_entry_safe(sas_port, p, &port->sas_port_del_list, del_list) { + list_del_init(&sas_port->del_list); + sas_port_delete(sas_port); + } +} + void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev) { if (!test_bit(SAS_DEV_DESTROY, &dev->state) && @@ -384,7 +385,6 @@ void sas_unregister_dev(struct asd_sas_p if (!test_and_set_bit(SAS_DEV_DESTROY, &dev->state)) { sas_rphy_unlink(dev->rphy); list_move_tail(&dev->disco_list_node, &port->destroy_list); - sas_discover_event(dev->port, DISCE_DESTRUCT); } }
@@ -490,6 +490,8 @@ static void sas_discover_domain(struct w port->port_dev = NULL; }
+ sas_probe_devices(port); + SAS_DPRINTK("DONE DISCOVERY on port %d, pid:%d, result:%d\n", port->id, task_pid_nr(current), error); } @@ -523,6 +525,10 @@ static void sas_revalidate_domain(struct port->id, task_pid_nr(current), res); out: mutex_unlock(&ha->disco_mutex); + + sas_destruct_devices(port); + sas_destruct_ports(port); + sas_probe_devices(port); }
/* ---------- Events ---------- */ @@ -578,10 +584,8 @@ void sas_init_disc(struct sas_discovery static const work_func_t sas_event_fns[DISC_NUM_EVENTS] = { [DISCE_DISCOVER_DOMAIN] = sas_discover_domain, [DISCE_REVALIDATE_DOMAIN] = sas_revalidate_domain, - [DISCE_PROBE] = sas_probe_devices, [DISCE_SUSPEND] = sas_suspend_devices, [DISCE_RESUME] = sas_resume_devices, - [DISCE_DESTRUCT] = sas_destruct_devices, };
disc->pending = 0; --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -1903,7 +1903,8 @@ static void sas_unregister_devs_sas_addr sas_port_delete_phy(phy->port, phy->phy); sas_device_set_phy(found, phy->port); if (phy->port->num_phys == 0) - sas_port_delete(phy->port); + list_add_tail(&phy->port->del_list, + &parent->port->sas_port_del_list); phy->port = NULL; } } @@ -2111,7 +2112,7 @@ int sas_ex_revalidate_domain(struct doma struct domain_device *dev = NULL;
res = sas_find_bcast_dev(port_dev, &dev); - while (res == 0 && dev) { + if (res == 0 && dev) { struct expander_device *ex = &dev->ex_dev; int i = 0, phy_id;
@@ -2123,9 +2124,6 @@ int sas_ex_revalidate_domain(struct doma res = sas_rediscover(dev, phy_id); i = phy_id + 1; } while (i < ex->num_phys); - - dev = NULL; - res = sas_find_bcast_dev(port_dev, &dev); } return res; } --- a/drivers/scsi/libsas/sas_internal.h +++ b/drivers/scsi/libsas/sas_internal.h @@ -100,6 +100,7 @@ int sas_try_ata_reset(struct asd_sas_phy void sas_hae_reset(struct work_struct *work);
void sas_free_device(struct kref *kref); +void sas_destruct_devices(struct asd_sas_port *port);
#ifdef CONFIG_SCSI_SAS_HOST_SMP extern int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req, --- a/drivers/scsi/libsas/sas_port.c +++ b/drivers/scsi/libsas/sas_port.c @@ -66,6 +66,7 @@ static void sas_resume_port(struct asd_s rc = sas_notify_lldd_dev_found(dev); if (rc) { sas_unregister_dev(port, dev); + sas_destruct_devices(port); continue; }
@@ -219,6 +220,7 @@ void sas_deform_port(struct asd_sas_phy
if (port->num_phys == 1) { sas_unregister_domain_devices(port, gone); + sas_destruct_devices(port); sas_port_delete(port->port); port->port = NULL; } else { @@ -323,6 +325,7 @@ static void sas_init_port(struct asd_sas INIT_LIST_HEAD(&port->dev_list); INIT_LIST_HEAD(&port->disco_list); INIT_LIST_HEAD(&port->destroy_list); + INIT_LIST_HEAD(&port->sas_port_del_list); spin_lock_init(&port->phy_list_lock); INIT_LIST_HEAD(&port->phy_list); port->ha = sas_ha; --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -87,10 +87,8 @@ enum discover_event { DISCE_DISCOVER_DOMAIN = 0U, DISCE_REVALIDATE_DOMAIN, DISCE_PORT_GONE, - DISCE_PROBE, DISCE_SUSPEND, DISCE_RESUME, - DISCE_DESTRUCT, DISC_NUM_EVENTS, };
@@ -274,6 +272,7 @@ struct asd_sas_port { struct list_head dev_list; struct list_head disco_list; struct list_head destroy_list; + struct list_head sas_port_del_list; enum sas_linkrate linkrate;
struct sas_work work; --- a/include/scsi/scsi_transport_sas.h +++ b/include/scsi/scsi_transport_sas.h @@ -145,6 +145,7 @@ struct sas_port {
struct mutex phy_list_mutex; struct list_head phy_list; + struct list_head del_list; /* libsas only */ };
#define dev_to_sas_port(d) \