A wait_event call with a stack local wait_queue_head_t structure that is
used to do the wake up for the wait_event is inherently racy. After the
wait_event finished the wake_up call might not have completed yet.
Replace the stack local wait_queue_head_t in tape_do_io and
tape_do_io_interruptible with a per device wait queue.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
A wait_event call with a stack local wait_queue_head_t structure that is
used to do the wake up for the wait_event is inherently racy. After the
wait_event finished the wake_up call might not have completed yet.
Remove the stack local wait_queue_head_t from raw3270_start_init and
use the global raw3270_wait_queue instead.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The driver incorrectly assumed that putchar will only be called from
schedulable process context and therefore blocked and waited if no
free output buffers where available.
Since putchar may also be called from BH context this may lead to
deadlocks.
To fix this just return the number of characters accepted and let the
upper layer handle the rest.
The console write function will busy wait (sclp_sync_wait) until a
buffer is available again.
Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This fixes the last remaining section mismatch warnings in s390
architecture code. It reveals also a real bug introduced by... me
with git commit 2069e978d5
("[S390] sparsemem vmemmap: initialize memmap.")
Calling the generic vmemmap_alloc_block() function to get initialized
memory is a nice idea, however that function is __meminit annotated
and therefore the function might be gone if we try to call it later.
This can happen if a DCSS segment gets added.
So basically revert the patch and clear the memmap explicitly to fix
the original bug.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Due to incorrect function call sequence it can happen that a tape block
request is finished before the request is taken from the block request queue.
The following sequence leads to that condition:
* tapeblock_start_request() -> start CCW program
* Request finishes -> IO interrupt
* tapeblock_end_request()
* end_that_request_last()
If blkdev_dequeue_request() has not been called before end_that_request_last(),
a kernel bug is triggered in end_that_request_last() because the request is
still queued. To solve that problem blkdev_dequeue_request() has to be called
before starting the CCW program.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
There is a race from when a device is created with device_create() and
then the drvdata is set with a call to dev_set_drvdata() in which a
sysfs file could be open, yet the drvdata will be NULL, causing all
sorts of bad things to happen.
This patch fixes the problem by using the new function,
device_create_drvdata().
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
To construct the integer containing the information from the bus_id,
it is easier to use the data from ccw_dev_id than to parse the bus_id.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove proc_root export. Creation and removal works well if parent PDE is
supplied as NULL -- it worked always that way.
So, one useless export removed and consistency added, some drivers created
PDEs with &proc_root as parent but removed them as NULL and so on.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the function that prints the segment warning messages found in the
monreader driver and the dcssblk driver to the extmem base code.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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>
When a tape device is set online, offline and online again, the following
error message is printed on the console: "sysfs: duplicate filename
'non-rewinding' can not be created". The reason is that when setting a
device online, the tape driver creates a sysfs symlink from the tape device
to the tape class device. Unfortunately the symlink is not removed
correctly, when the device is set offline. Instead of passing the
tape device object to sysfs_remove_link, the class device object is used.
This patch fixes this problem and uses the correct tape device object now.
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>
Reintroduces in_interrupt() check in sclp_tty code. Add may_schedule
parameter to vt220 write function, so we can let the write function
know if it may schedule or not. So we disallow scheduling for all
console calls and may allow them for tty calls.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Currently an output buffer can wait up to HZ/2 until the buffer is
flushed. The wait time is noticeable in interactive tools like mc.
Change the value to HZ/20, which seems enough for interactive work.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Oddly enough, unsigned int c = '\300'; puts a "negative" value in c, not
0300... This fixes the default unicode compose table by using integers
instead of character constants.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make state change events adjust the correct mask by cleaning up
naming inconsistencies. Also remove chance for lockup by removing
unnecessary mask related check before reading events.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
There are two problems in the vt220 intialization:
o Currently the vt220 console looses early printk events until the
the vt220 tty is registered.
o console should work if tty_register fails
sclp_vt220_con_init calls __sclp_vt220_init and register_console.
It does not register the driver with the sclp core code via
sclp_register. That results in an sclp_send_mask=0. Therefore,
__sclp_vt220_emit will reject buffers with EIO. Unfortunately
register_console will cause the printk buffer to be sent to the
console and, therefore, every early message gets dropped. The
sclp_send_mask is set later during boot, when sclp_vt220_tty_init
calls sclp_register.
The solution is to move the sclp_register call from sclp_vt220_tty_init
to __sclp_vt220_init. This makes sure that the console is properly
registered with the sclp subsystem before the first log buffer messages
are passed to the vt220 console.
We also adopt the cleanup on error to keep the console alive if
tty_register fails.
Thanks to Peter Oberparleiter and Heiko Carstens for review and ideas
for improvement.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Under load the following bug message appeared while using sysrq-t:
BUG: scheduling while atomic: bash/3662/0x00000004
0000000000105b74 000000003ba17740 0000000000000002 0000000000000000
000000003ba177e0 000000003ba17758 000000003ba17758 0000000000105bfe
0000000000817ba8 000000003f2a5350 0000000000000000 0000000000000000
000000003ba17740 000000000000000c 000000003ba17740 000000003ba177b0
0000000000568630 0000000000105bfe 000000003ba17740 000000003ba17790
Call Trace:
([<0000000000105b74>] show_trace+0x13c/0x158)
[<0000000000105c58>] show_stack+0xc8/0xfc
[<0000000000105cbc>] dump_stack+0x30/0x40
[<000000000012a0c8>] __schedule_bug+0x84/0x94
[<000000000056234e>] schedule+0x5ea/0x970
[<0000000000477cd2>] __sclp_vt220_write+0x1f6/0x3ec
[<0000000000477f00>] sclp_vt220_con_write+0x38/0x48
[<0000000000130b4a>] __call_console_drivers+0xbe/0xd8
[<0000000000130bf0>] _call_console_drivers+0x8c/0xd0
[<0000000000130eea>] release_console_sem+0x1a6/0x2fc
[<0000000000131786>] vprintk+0x262/0x480
[<00000000001319fa>] printk+0x56/0x68
[<0000000000125aaa>] print_cfs_rq+0x45e/0x4a4
[<000000000012614e>] sched_debug_show+0x65e/0xee8
[<000000000012a8fc>] show_state_filter+0x1cc/0x1f0
[<000000000044d39c>] sysrq_handle_showstate+0x2c/0x3c
[<000000000044d1fe>] __handle_sysrq+0xae/0x18c
[<00000000002001f2>] write_sysrq_trigger+0x8a/0x90
[<00000000001f7862>] proc_reg_write+0x9a/0xc4
[<00000000001a83d4>] vfs_write+0xb8/0x174
[<00000000001a8b88>] sys_write+0x58/0x8c
[<0000000000112e7c>] sysc_noemu+0x10/0x16
[<0000020000116f68>] 0x20000116f68
The problem seems to be, that with a full console buffer, release_console_sem
disables interrupts with spin_lock_irqsave and then calls the console function
without enabling interrupts. __sclp_vt220_write checks for in_interrupt, to
decide if it can schedule. It should check for in_atomic instead.
The same is true for sclp_tty.c.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
