On Mon, 4 Aug 2003, Jani Monoses wrote:
> Hi
> as reported by someone earlier this year there's a long stack_dump
> starting from kobject_register failed with -17 (EEXISTS) when ide-cs
> detects a CF card.
> The reason is as I see it that both rescan_partitions and register_disk
I think I know how this happens:
register_disk()->blkdev_get()->do_open(), then disk->fops->open()
(idedisk_open() for ide-disk) calls check_disk_change().
check_disk_change() calls disk->fops->media_changed().
idedisk_media_changes() returns drive->removable, so instead of returning
from check_disk_change() block_device is invalidated
and bdev->bd_invalidated is set to 1. Later in do_open(),
bdev->bd_invalidated flag is checked and since it is 1 rescan_partitions()
is triggered. Thus partitions are checked and added twice:
in do_open()->rescan_partitions() and in register_disk().
[ The same applies to ide-floppy driver and probably some other drivers. ]
Ufff... I hope it is a correct description (I don't have hardware to
reproduce the problem).
Easy way is to fix is to add drive->attach flag, set it in
idedisk_attach() and check+clear in idedisk_media_changed(),
but I don't like this solution (patch below, Jani, can you test it?).
Any other ideas?
> are called, both of which in turn call add_partition for all partitions
> on the CF card. add_partition calls kobject_register. Also devfs_mk_bdev
> is called twice but it only prints an error msg 'could not append...'. I
> don't know if that is how things should be called or whether kobjects
> for IDE are broken as Alan responded to that earlier post but apart from
> this initial stack_dump the card works fine (not eject of course) So is
> kobject_register to verbose or calling code should make sure it does not
> attempt to register the same object multiple times?
It is a bug to try to register some objects multiple times,
not a feature :-).
> 2.6.0-test2
Thanks,
-- Bartlomiejdrivers/ide/ide-disk.c | 7 +++++++ drivers/ide/ide-floppy.c | 8 +++++++- include/linux/ide.h | 1 + 3 files changed, 15 insertions(+), 1 deletion(-)
diff -puN drivers/ide/ide-disk.c~ide-attach-flag drivers/ide/ide-disk.c --- linux-2.6.0-test2-bk3/drivers/ide/ide-disk.c~ide-attach-flag 2003-08-05 01:43:03.312872768 +0200 +++ linux-2.6.0-test2-bk3-root/drivers/ide/ide-disk.c 2003-08-05 01:48:44.197050496 +0200 @@ -1790,6 +1790,12 @@ static int idedisk_ioctl(struct inode *i static int idedisk_media_changed(struct gendisk *disk) { ide_drive_t *drive = disk->private_data; + + /* do not scan partitions twice if we are attaching this device */ + if (drive->attach) { + drive->attach = 0; + return 0; + } /* if removable, always assume it was changed */ return drive->removable; } @@ -1848,6 +1854,7 @@ static int idedisk_attach(ide_drive_t *d g->flags = drive->removable ? GENHD_FL_REMOVABLE : 0; set_capacity(g, current_capacity(drive)); g->fops = &idedisk_ops; + drive->attach = 1; add_disk(g); return 0; failed: diff -puN drivers/ide/ide-floppy.c~ide-attach-flag drivers/ide/ide-floppy.c --- linux-2.6.0-test2-bk3/drivers/ide/ide-floppy.c~ide-attach-flag 2003-08-05 01:43:06.710356272 +0200 +++ linux-2.6.0-test2-bk3-root/drivers/ide/ide-floppy.c 2003-08-05 01:48:59.546716992 +0200 @@ -2006,7 +2006,12 @@ static int idefloppy_media_changed(struc { ide_drive_t *drive = disk->private_data; idefloppy_floppy_t *floppy = drive->driver_data; - + + /* do not scan partitions twice if we are attaching this device */ + if (drive->attach) { + drive->attach = 0; + return 0; + } return test_and_clear_bit(IDEFLOPPY_MEDIA_CHANGED, &floppy->flags); }
@@ -2061,6 +2066,7 @@ static int idefloppy_attach (ide_drive_t strcpy(g->devfs_name, drive->devfs_name); g->flags = drive->removable ? GENHD_FL_REMOVABLE : 0; g->fops = &idefloppy_ops; + drive->attach = 1; add_disk(g); return 0; failed: diff -puN include/linux/ide.h~ide-attach-flag include/linux/ide.h --- linux-2.6.0-test2-bk3/include/linux/ide.h~ide-attach-flag 2003-08-05 01:43:14.735136320 +0200 +++ linux-2.6.0-test2-bk3-root/include/linux/ide.h 2003-08-05 01:45:19.069234664 +0200 @@ -711,6 +711,7 @@ typedef struct ide_drive_s { unsigned id_read : 1; /* 1=id read from disk 0 = synthetic */ unsigned noprobe : 1; /* from: hdx=noprobe */ unsigned removable : 1; /* 1 if need to do check_media_change */ + unsigned attach : 1; /* set to 1 in ->attach() */ unsigned is_flash : 1; /* 1 if probed as flash */ unsigned forced_geom : 1; /* 1 if hdx=c,h,s was given at boot */ unsigned no_unmask : 1; /* disallow setting unmask bit */
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This archive was generated by hypermail 2b29 : Thu Aug 07 2003 - 22:00:25 EST