From: Rafael J. Wysocki Organization: SUSE To: Arjan van de Ven CC: Linus Torvalds OK, updated patch follows, with a changelog. I've added this check to user.c too, because that code can be called independently of the one in disk.c . Also, if resume is user space-driven, it's a good idea to wait for all of the device probes to complete before continuing. Thanks, Rafael --- From: Rafael J. Wysocki Subject: 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 --- drivers/scsi/scsi_priv.h | 3 --- drivers/scsi/scsi_wait_scan.c | 2 +- include/scsi/scsi_scan.h | 11 +++++++++++ kernel/power/disk.c | 8 ++++++++ kernel/power/user.c | 9 +++++++++ 5 files changed, 29 insertions(+), 4 deletions(-) Index: linux-2.6/include/scsi/scsi_scan.h =================================================================== --- /dev/null +++ linux-2.6/include/scsi/scsi_scan.h @@ -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 */ Index: linux-2.6/drivers/scsi/scsi_priv.h =================================================================== --- linux-2.6.orig/drivers/scsi/scsi_priv.h +++ linux-2.6/drivers/scsi/scsi_priv.h @@ -38,9 +38,6 @@ static inline void scsi_log_completion(s { }; #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, Index: linux-2.6/drivers/scsi/scsi_wait_scan.c =================================================================== --- linux-2.6.orig/drivers/scsi/scsi_wait_scan.c +++ linux-2.6/drivers/scsi/scsi_wait_scan.c @@ -11,7 +11,7 @@ */ #include -#include "scsi_priv.h" +#include static int __init wait_scan_init(void) { Index: linux-2.6/kernel/power/disk.c =================================================================== --- linux-2.6.orig/kernel/power/disk.c +++ linux-2.6/kernel/power/disk.c @@ -22,5 +22,6 @@ #include #include #include +#include #include "power.h" @@ -645,6 +646,13 @@ static int software_resume(void) 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 * trigger path is via sysfs which takes a buffer mutex before Index: linux-2.6/kernel/power/user.c =================================================================== --- linux-2.6.orig/kernel/power/user.c +++ linux-2.6/kernel/power/user.c @@ -24,6 +24,7 @@ #include #include #include +#include #include @@ -92,6 +93,7 @@ static int snapshot_open(struct inode *i 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 *i 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);