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PM/Hibernate: Wait for SCSI devices scan to complete during resume 

There is a race between resume from hibernation and the asynchronous
scanning of SCSI devices and to prevent it from happening we need to
call scsi_complete_async_scans() during resume from hibernation.

In addition, if the resume from hibernation is userland-driven, it's
better to wait for all device probes in the kernel to complete before
attempting to open the resume device.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rafael J. Wysocki 2009-04-12 20:06:56 +02:00 committed by Linus Torvalds
parent 7b11428d37
commit c751085943
5 changed files with 29 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/scsi/scsi_priv.h
View File

@ -38,9 +38,6 @@ static inline void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
{ };
#endif
/* scsi_scan.c */
int scsi_complete_async_scans(void);
/* scsi_devinfo.c */
extern int scsi_get_device_flags(struct scsi_device *sdev,
const unsigned char *vendor,

2
drivers/scsi/scsi_wait_scan.c
View File

@ -11,7 +11,7 @@
*/
#include <linux/module.h>
#include "scsi_priv.h"
#include <scsi/scsi_scan.h>
static int __init wait_scan_init(void)
{

11
include/scsi/scsi_scan.h Normal file
View File

@ -0,0 +1,11 @@
#ifndef _SCSI_SCSI_SCAN_H
#define _SCSI_SCSI_SCAN_H
#ifdef CONFIG_SCSI
/* drivers/scsi/scsi_scan.c */
extern int scsi_complete_async_scans(void);
#else
static inline int scsi_complete_async_scans(void) { return 0; }
#endif
#endif /* _SCSI_SCSI_SCAN_H */

8
kernel/power/disk.c
View File

@ -22,6 +22,7 @@
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <scsi/scsi_scan.h>
#include <asm/suspend.h>
#include "power.h"
@ -644,6 +645,13 @@ static int software_resume(void)
if (noresume)
return 0;
/*
* We can't depend on SCSI devices being available after loading one of
* their modules if scsi_complete_async_scans() is not called and the
* resume device usually is a SCSI one.
*/
scsi_complete_async_scans();
/*
* name_to_dev_t() below takes a sysfs buffer mutex when sysfs
* is configured into the kernel. Since the regular hibernate

9
kernel/power/user.c
View File

@ -24,6 +24,7 @@
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <linux/smp_lock.h>
#include <scsi/scsi_scan.h>
#include <asm/uaccess.h>
@ -92,6 +93,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
filp->private_data = data;
memset(&data->handle, 0, sizeof(struct snapshot_handle));
if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
/* Hibernating. The image device should be accessible. */
data->swap = swsusp_resume_device ?
swap_type_of(swsusp_resume_device, 0, NULL) : -1;
data->mode = O_RDONLY;
@ -99,6 +101,13 @@ static int snapshot_open(struct inode *inode, struct file *filp)
if (error)
pm_notifier_call_chain(PM_POST_HIBERNATION);
} else {
/*
* Resuming. We may need to wait for the image device to
* appear.
*/
wait_for_device_probe();
scsi_complete_async_scans();
data->swap = -1;
data->mode = O_WRONLY;
error = pm_notifier_call_chain(PM_RESTORE_PREPARE);