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authorLinus Torvalds <torvalds@linux-foundation.org>2012-07-19 05:15:46 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-19 05:15:46 +0400
commiteea03c20ae38a55405c0865ed9adfccc400e4c8e (patch)
tree09800af230cd1ef6d9d83ac5e057d8085feca601 /drivers/base
parente2f3b78557ff11f58d836e016900c3210f4fb1c1 (diff)
downloadlinux-eea03c20ae38a55405c0865ed9adfccc400e4c8e.tar.xz
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 <t.artem@mailcity.com> Cc: Dan Williams <dan.j.williams@gmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: James Bottomley <jbottomley@parallels.com> Cc: Borislav Petkov <bp@amd64.org> Cc: linux-scsi <linux-scsi@vger.kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/dd.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index dcb8a6e48692..4b01ab3d2c24 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -24,6 +24,7 @@
#include <linux/wait.h>
#include <linux/async.h>
#include <linux/pm_runtime.h>
+#include <scsi/scsi_scan.h>
#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);