On 21/05/2020 05:30, 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.
Apart from nit, it looks ok. Cheers, John
Fixes: 130f4caf145c ("libata: Ensure ata_port probe has completed before detach") BugLink: https://bugs.launchpad.net/bugs/1867983 Suggested-by: John Garry <john.garry@xxxxxxxxxx> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> --- v2: - Sync up to cookie + 1. - Squash the synchronization into the same loop. drivers/ata/libata-core.c | 9 ++++----- include/linux/libata.h | 3 +++ 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index beca5f91bb4c..b6be84f2cecb 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;@@ -5921,10 +5920,10 @@ void ata_host_detach(struct ata_host *host) int i;/* Ensure ata_port probe has completed */
nit: maybe we can relocate this comment
- async_synchronize_full(); - - for (i = 0; i < host->n_ports; i++) + for (i = 0; i < host->n_ports; i++) { + 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 cffa4714bfa8..ae6dfc107ea8 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;
