libata: Use per port sync for detach

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")
Suggested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: John Garry <john.garry@huawei.com>
BugLink: https://bugs.launchpad.net/bugs/1867983
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 69361ec..b1cd4d9 100644 (file)
--- 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 af83285..8a48437 100644 (file)
--- 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;