From eea03c20ae38a55405c0865ed9adfccc400e4c8e Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 18 Jul 2012 18:15:46 -0700 Subject: [PATCH] Make wait_for_device_probe() also do scsi_complete_async_scans() Commit a7a20d103994 ("sd: limit the scope of the async probe domain") make the SCSI device probing run device discovery in it's own async domain. However, as a result, the partition detection was no longer synchronized by async_synchronize_full() (which, despite the name, only synchronizes the global async space, not all of them). Which in turn meant that "wait_for_device_probe()" would not wait for the SCSI partitions to be parsed. And "wait_for_device_probe()" was what the boot time init code relied on for mounting the root filesystem. Now, most people never noticed this, because not only is it timing-dependent, but modern distributions all use initrd. So the root filesystem isn't actually on a disk at all. And then before they actually mount the final disk filesystem, they will have loaded the scsi-wait-scan module, which not only does the expected wait_for_device_probe(), but also does scsi_complete_async_scans(). [ Side note: scsi_complete_async_scans() had also been partially broken, but that was fixed in commit 43a8d39d0137 ("fix async probe regression"), so that same commit a7a20d103994 had actually broken setups even if you used scsi-wait-scan explicitly ] Solve this problem by just moving the scsi_complete_async_scans() call into wait_for_device_probe(). Everybody who wants to wait for device probing to finish really wants the SCSI probing to complete, so there's no reason not to do this. So now "wait_for_device_probe()" really does what the name implies, and properly waits for device probing to finish. This also removes the now unnecessary extra calls to scsi_complete_async_scans(). Reported-and-tested-by: Artem S. Tashkinov Cc: Dan Williams Cc: Alan Stern Cc: James Bottomley Cc: Borislav Petkov Cc: linux-scsi Signed-off-by: Linus Torvalds --- drivers/base/dd.c | 2 ++ drivers/scsi/scsi_wait_scan.c | 5 ----- include/linux/device.h | 2 -- kernel/power/hibernate.c | 8 -------- kernel/power/user.c | 2 -- 5 files changed, 2 insertions(+), 17 deletions(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index dcb8a6e4869..4b01ab3d2c2 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -24,6 +24,7 @@ #include #include #include +#include #include "base.h" #include "power/power.h" @@ -332,6 +333,7 @@ void wait_for_device_probe(void) /* wait for the known devices to complete their probing */ wait_event(probe_waitqueue, atomic_read(&probe_count) == 0); async_synchronize_full(); + scsi_complete_async_scans(); } EXPORT_SYMBOL_GPL(wait_for_device_probe); diff --git a/drivers/scsi/scsi_wait_scan.c b/drivers/scsi/scsi_wait_scan.c index ae781487461..07273453887 100644 --- a/drivers/scsi/scsi_wait_scan.c +++ b/drivers/scsi/scsi_wait_scan.c @@ -22,11 +22,6 @@ static int __init wait_scan_init(void) * and might not yet have reached the scsi async scanning */ wait_for_device_probe(); - /* - * and then we wait for the actual asynchronous scsi scan - * to finish. - */ - scsi_complete_async_scans(); return 0; } diff --git a/include/linux/device.h b/include/linux/device.h index 161d96241b1..6de94151ff6 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -865,8 +865,6 @@ extern int (*platform_notify_remove)(struct device *dev); extern struct device *get_device(struct device *dev); extern void put_device(struct device *dev); -extern void wait_for_device_probe(void); - #ifdef CONFIG_DEVTMPFS extern int devtmpfs_create_node(struct device *dev); extern int devtmpfs_delete_node(struct device *dev); diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 8b53db38a27..238025f5472 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -27,7 +27,6 @@ #include #include #include -#include #include "power.h" @@ -748,13 +747,6 @@ static int software_resume(void) async_synchronize_full(); } - /* - * We can't depend on SCSI devices being available after loading - * one of their modules until scsi_complete_async_scans() is - * called and the resume device usually is a SCSI one. - */ - scsi_complete_async_scans(); - swsusp_resume_device = name_to_dev_t(resume_file); if (!swsusp_resume_device) { error = -ENODEV; diff --git a/kernel/power/user.c b/kernel/power/user.c index 91b0fd021a9..4ed81e74f86 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -24,7 +24,6 @@ #include #include #include -#include #include @@ -84,7 +83,6 @@ static int snapshot_open(struct inode *inode, struct file *filp) * appear. */ wait_for_device_probe(); - scsi_complete_async_scans(); data->swap = -1; data->mode = O_WRONLY; -- 2.41.0