Commit b5292111 authored by Kai-Heng Feng's avatar Kai-Heng Feng Committed by Jens Axboe
Browse files

libata: Use per port sync for detach 



Commit 130f4caf ("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: 130f4caf ("libata: Ensure ata_port probe has completed before detach")
Suggested-by: default avatarJohn Garry <john.garry@huawei.com>
Signed-off-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: default avatarJohn Garry <john.garry@huawei.com>
BugLink: https://bugs.launchpad.net/bugs/1867983


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f650ef61

drivers/ata/libata-core.c

+5 −6
Original line number Diff line number Diff line
@@ -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;



	for (i = 0; i < host->n_ports; i++) {

		/* Ensure ata_port probe has completed */

	async_synchronize_full();



	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);

include/linux/libata.h

+3 −0
Original line number Diff line number Diff line
@@ -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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