Messages in this thread | | | Subject | Re: [PATCH v3] libata: Use per port sync for detach | From | John Garry <> | Date | Wed, 3 Jun 2020 09:40:54 +0100 |
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On 03/06/2020 08:48, Kai-Heng Feng wrote: > Commit 130f4caf145c ("libata: Ensure ata_port probe has completed before > detach") may cause system freeze during suspend. > > Using async_synchronize_full() in PM callbacks is wrong, since async > callbacks that are already scheduled may wait for not-yet-scheduled > callbacks, causes a circular dependency. > > Instead of using big hammer like async_synchronize_full(), use async > cookie to make sure port probe are synced, without affecting other > scheduled PM callbacks. > > Fixes: 130f4caf145c ("libata: Ensure ata_port probe has completed before detach") > BugLink: https://bugs.launchpad.net/bugs/1867983 > Suggested-by: John Garry <john.garry@huawei.com> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
thanks, Tested-by: John Garry <john.garry@huawei.com>
> --- > v3: > - Move the comment to properly align with the code. > > v2: > - Sync up to cookie + 1. > - Squash the synchronization into the same loop. > > drivers/ata/libata-core.c | 11 +++++------ > include/linux/libata.h | 3 +++ > 2 files changed, 8 insertions(+), 6 deletions(-) > > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c > index 69361ec43db5..b1cd4d97bc2a 100644 > --- a/drivers/ata/libata-core.c > +++ b/drivers/ata/libata-core.c > @@ -42,7 +42,6 @@ > #include <linux/workqueue.h> > #include <linux/scatterlist.h> > #include <linux/io.h> > -#include <linux/async.h> > #include <linux/log2.h> > #include <linux/slab.h> > #include <linux/glob.h> > @@ -5778,7 +5777,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht) > /* perform each probe asynchronously */ > for (i = 0; i < host->n_ports; i++) { > struct ata_port *ap = host->ports[i]; > - async_schedule(async_port_probe, ap); > + ap->cookie = async_schedule(async_port_probe, ap); > } > > return 0; > @@ -5920,11 +5919,11 @@ void ata_host_detach(struct ata_host *host) > { > int i; > > - /* Ensure ata_port probe has completed */ > - async_synchronize_full(); > - > - for (i = 0; i < host->n_ports; i++) > + for (i = 0; i < host->n_ports; i++) { > + /* Ensure ata_port probe has completed */ > + async_synchronize_cookie(host->ports[i]->cookie + 1); > ata_port_detach(host->ports[i]); > + } > > /* the host is dead now, dissociate ACPI */ > ata_acpi_dissociate(host); > diff --git a/include/linux/libata.h b/include/linux/libata.h > index af832852e620..8a4843704d28 100644 > --- a/include/linux/libata.h > +++ b/include/linux/libata.h > @@ -22,6 +22,7 @@ > #include <linux/acpi.h> > #include <linux/cdrom.h> > #include <linux/sched.h> > +#include <linux/async.h> > > /* > * Define if arch has non-standard setup. This is a _PCI_ standard > @@ -872,6 +873,8 @@ struct ata_port { > struct timer_list fastdrain_timer; > unsigned long fastdrain_cnt; > > + async_cookie_t cookie; > + > int em_message_type; > void *private_data; > >
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