Commit graph

5 commits

Author SHA1 Message Date
Frank Munzert
a695f16729 [S390] vmur: Use wait queue instead of mutex to serialize open
If user space opens a unit record device node then vmur is leaving the kernel
with lock open_mutex still held to prevent other processes from opening the
device simultaneously. This causes lockdep to complain about a lock held when
returning to user space.
Now the mutex is replaced by a wait queue to serialize device open.

Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 07:46:59 +02:00
Michael Holzheu
8127a1f80a [S390] vmur: fix reference counting for vmur device structure
When a vmur device is removed due to a detach of the device, currently the
ur device structure is freed. Unfortunately it can happen, that there is
still a user of the device structure, when the character device is open
during the detach process. To fix this, reference counting for the vmur
structure is introduced.
In addition to that, the online, offline, probe and remove functions are
serialized now using a global mutex.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-08-22 13:51:48 +02:00
Michael Holzheu
4eac34529b [S390] vmur: add "top of queue" sanity check for reader open
If the z/VM reader is already open, it can happen that after opening the
Linux reader device, not the topmost file is processed. According the
semantics of the Linux z/VM unit record device driver, always the topmost
file has to be processed. With this fix an error is returned if that is
not the case.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-08-10 14:32:38 +02:00
Michael Holzheu
f2405598e0 [S390] vmur: reject open on z/VM reader files with status HOLD
If a reader file with HOLD status is at the top of the reader queue, currently
all read requests will return data of the second file in the queue. But the
semantics of vmur is that always the topmost file is read. With this fix
-EPERM is returned on open, if the topmost reader file is in HOLD status.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-08-10 14:32:37 +02:00
Frank Munzert
810cb5b32d [S390] z/VM unit record device driver
z/VM Unit record character device driver to access VM reader, punch,
and printer.

Signed-off-by: Frank Munzert <munzert@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-07-17 13:36:19 +02:00