linux-toradex.git/drivers/s390/block/dasd_ioctl.c, branch v3.2.39

compat: fix compile breakage on s390

2012-03-12T19:31:22+00:00

commit 048cd4e51d24ebf7f3552226d03c769d6ad91658 upstream.

The new is_compat_task() define for the !COMPAT case in
include/linux/compat.h conflicts with a similar define in
arch/s390/include/asm/compat.h.

This is the minimal patch which fixes the build issues.

Signed-off-by: Heiko Carstens 
Signed-off-by: Linus Torvalds 
Cc: Jonathan Nieder 
Signed-off-by: Greg Kroah-Hartman

[S390] drivers/s390/block/dasd_ioctl.c: add missing kfree

2011-08-24T15:15:23+00:00

Data is only used to temporarily hold information to be copied to the user
level, so it should be freed before leaving the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@exists@
local idexpression x;
statement S,S1;
expression E;
identifier fl;
expression *ptr != NULL;
@@

x = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...kfree(x)...+> }
     when any
     when != true x == NULL
x->fl
...>
(
if (x == NULL) S1
|
if (...) { ... when != x
               when forall
(
 return \(0\|<+...x...+>\|ptr\);
|
* return ...;
)
}
)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] dasd: add enhanced DASD statistics interface

2011-07-24T08:48:23+00:00

This patch extends the DASD statistics to allow for a more detailed
analysis of DASD I/O operations. In particular we want the statistics
to provide answers to the following questions:
- How many requests used a PAV alias?
- How many requests used High Performance FICON?
- How do read request perform versus write requests?

The existing DASD statistics interface has several shortcomings
- The interface for global data is a formatted text table in procfs
  (/proc/dasd/statistics). The layout is meant for human readers and
  is not to easy to parse. If values get to large for the table
  layout, they get scaled down.
- The statistics which are collected per block device can be
  accessed via an ioctl interface, which can only be extended by
  defining a new ioctl.
- There is no statistics interface for individual PAV base and alias
  devices.

To overcome theses shortcomings we create a new DASD statistics
interface in debugfs. This interface will contain one entry for global
data, one per DASD block device, and one per DASD base and alias
device. Each file contains the statistic data in easy to parse
name/value and name/array pairs. The existing interfaces will remain
functional, but they will not be extended.

Signed-off-by: Stefan Weinhuber 
Signed-off-by: Martin Schwidefsky

[S390] dasd: fix race between open and offline

2011-04-20T08:15:43+00:00

The dasd_open function uses the private_data pointer of the gendisk to
find the dasd_block structure that matches the gendisk. When a DASD
device is set offline, we set the private_data pointer of the gendisk
to NULL and later remove the dasd_block structure, but there is still
a small race window, in which dasd_open could first read a pointer
from the private_data field and then try to use it, after the structure
has already been freed.
To close this race window, we will store a pointer to the dasd_devmap
structure of the base device in the private_data field. The devmap
entries are not deleted, and we already have proper locking and
reference counting in place, so that we can safely get from a devmap
pointer to the dasd_device and dasd_block structures of the device.

Signed-off-by: Stefan Weinhuber 
Signed-off-by: Martin Schwidefsky

s390/block: kill the big kernel lock

2010-09-26T14:25:51+00:00

The dasd and dcssblk drivers gained the big
kernel lock in the recent pushdown from the
block layer, but they don't really need it,
so remove the calls without a replacement.

Signed-off-by: Arnd Bergmann 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: linux-s390@vger.kernel.org

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

[S390] dasd: automatic recognition of read-only devices

2010-03-08T11:26:27+00:00

In z/VM it is possible to attach a device as read-only. To prevent
unintentional write requests and subsequent I/O errors, we can detect
this configuration using the z/VM DIAG 210 interface and set the
respective linux block device to read-only as well.

Signed-off-by: Stefan Weinhuber 
Signed-off-by: Martin Schwidefsky

[S390] dasd: fix possible NULL pointer errors

2010-01-27T09:12:48+00:00

Fix possible NULL pointer in DASD messages and correct discipline
checking.

Signed-off-by: Stefan Haberland 
Signed-off-by: Martin Schwidefsky

[S390] dasd: add missing compat ptr conversion

2010-01-13T19:44:44+00:00

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] dasd: improve error recovery for internal I/O

2009-12-07T11:51:34+00:00

Most of the error conditions reported by a FICON storage server
indicate situations which can be recovered. Sometimes the host just
needs to retry an I/O request, but sometimes the recovery
is more complex and requires the device driver to wait, choose
a different path, etc.

The DASD device driver has a fully featured error recovery
for normal block layer I/O, but not for internal I/O request which
are for example used during the device bring up.
This can lead to situations where the IPL of a system fails because
DASD devices are not properly recognized.
This patch will extend the internal I/O handling to use the existing
error recovery procedures.

Signed-off-by: Stefan Weinhuber 
Signed-off-by: Martin Schwidefsky