From c751085943362143f84346d274e0011419c84202 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 12 Apr 2009 20:06:56 +0200 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 Acked-by: Arjan van de Ven Signed-off-by: Linus Torvalds --- kernel/power/disk.c | 8 ++++++++ kernel/power/user.c | 9 +++++++++ 2 files changed, 17 insertions(+) (limited to 'kernel/power') diff --git a/kernel/power/disk.c b/kernel/power/disk.c index 5f21ab2bbcdf..0854770b63b9 100644 --- a/kernel/power/disk.c +++ b/kernel/power/disk.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #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 diff --git a/kernel/power/user.c b/kernel/power/user.c index 6c85359364f2..ed97375daae9 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -24,6 +24,7 @@ #include #include #include +#include #include @@ -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); -- cgit v1.2.3