The patch titled
fix ide-cs hang after device removal
has been removed from the -mm tree. Its filename was
fix-ide-cs-hang-after-device-removal.patch
This patch was dropped because it had testing failures
------------------------------------------------------
Subject: fix ide-cs hang after device removal
From: Anton Vorontsov <cbou@xxxxxxx>
I've caught deadlock inside IDE layer using IDE-CS: after accessing to IDE
disk placed in PCMCIA (CF card really), it will never probe again after
pulling it from PCMCIA/CF.
The kernel is stuck at
drivers/ide/ide.c:ide_unregister():604:
602 spin_unlock_irq(&ide_lock);
603 device_unregister(&drive->gendev);
604 wait_for_completion(&drive->gendev_rel_comp);
605 spin_lock_irq(&ide_lock);
ide_unregister() assumes that device_unregister() will call
ide-probe.c:drive_release_dev():
1282 static void drive_release_dev (struct device *dev)
1283 {
.... [...]
1302 complete(&drive->gendev_rel_comp);
1303 }
1311 static void init_gendisk (ide_hwif_t *hwif)
1312 {
....
1323 drive->gendev.release = drive_release_dev;
....
1333 }
But release() function will not called because drive->gendev is still
referenced inside genhd layer.
No need to get_device(driverfs_dev), because it's already gotten by
add_disk(). And no function will call put_device() second time. This is the
source of deadlock[1] in IDE layer.
[1] deadlock in ide_unregister()
at wait_for_completion(&drive->gendev_rel_comp) after
device_unregister(&drive->gendev). That happens by reason of
ide-probe.c:drive_release_dev() not called because of driverfs_dev (which is
drive->gendev) still referenced by add_disk().
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/partitions/check.c | 5 ++---
1 files changed, 2 insertions(+), 3 deletions(-)
diff -puN fs/partitions/check.c~fix-ide-cs-hang-after-device-removal fs/partitions/check.c
--- a/fs/partitions/check.c~fix-ide-cs-hang-after-device-removal
+++ a/fs/partitions/check.c
@@ -389,7 +389,7 @@ static char *make_block_name(struct gend
static int disk_sysfs_symlinks(struct gendisk *disk)
{
- struct device *target = get_device(disk->driverfs_dev);
+ struct device *target = disk->driverfs_dev;
int err;
char *disk_name = NULL;
@@ -425,9 +425,8 @@ err_out_dev_link:
sysfs_remove_link(&disk->kobj, "device");
err_out_disk_name:
kfree(disk_name);
-err_out:
- put_device(target);
}
+err_out:
return err;
}
_
Patches currently in -mm which might be from cbou@xxxxxxx are
fix-ide-cs-hang-after-device-removal.patch
-
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