Commit c7510859 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
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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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7b11428d
......@@ -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,
......
......@@ -11,7 +11,7 @@
*/
#include <linux/module.h>
#include "scsi_priv.h"
#include <scsi/scsi_scan.h>
static int __init wait_scan_init(void)
{
......
#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 */
......@@ -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
......
......@@ -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);
......
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