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authorKai-Heng Feng <kai.heng.feng@canonical.com>2020-06-03 15:48:19 +0800
committerJens Axboe <axboe@kernel.dk>2020-06-18 09:21:40 -0600
commitb5292111de9bb70cba3489075970889765302136 (patch)
tree086231488b2186326546bdc7a7c7c18e9175250c
parentf650ef61e040bcb175dd8762164b00a5d627f20e (diff)
downloadlinux-b5292111de9bb70cba3489075970889765302136.tar.gz
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>
-rw-r--r--drivers/ata/libata-core.c11
-rw-r--r--include/linux/libata.h3
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;