litmus-rt.git/drivers/scsi/osd, branch v2.6.33

[SCSI] libosd: Fix blk_put_request locking again

2009-12-10T14:54:17+00:00

So libosd has decided to sacrifice some code simplicity for the sake of
a clean API. One of these things is the possibility for users to call
osd_end_request, in any condition at any state. This opens up some
problems with calling blk_put_request when out-side of the completion
callback but calling __blk_put_request when detecting a from-completion
state.

The current hack was working just fine until exofs decided to operate on
all devices in parallel and wait for the sum of the requests, before
deallocating all osd-requests at once. There are two new possible cases
1. All request in a group are deallocated as part of the last request's
   async-done, request_queue is locked.
2. All request in a group where executed asynchronously, but
   de-allocation was delayed to after the async-done, in the context of
   another thread. Async execution but request_queue is not locked.

The solution I chose was to separate the deallocation of the osd_request
which has the information users need, from the deallocation of the
internal(2) requests which impose the locking problem. The internal
block-requests are freed unconditionally inside the async-done-callback,
when we know the queue is always locked. If at osd_end_request time we
still have a bock-request, then we know it did not come from within an
async-done-callback and we can call the regular blk_put_request.

The internal requests were used for carrying error information after
execution. This information is now copied to osd_request members for
later analysis by user code.

The external API and behaviour was unchanged, except now it really
supports what was previously advertised.

Reported-by: Vineet Agarwal 
Signed-off-by: Boaz Harrosh 
Cc: Stable Tree 
Signed-off-by: James Bottomley

[SCSI] libosd: Error handling revamped

2009-12-04T18:01:47+00:00

Administer some love to the osd_req_decode_sense function

* Fix a bad bug with osd_req_decode_sense(). If there was no scsi
  residual, .i.e the request never reached the target, then all the
  osd_sense_info members where garbage.

* Add grossly missing in/out_resid to osd_sense_info and fill them in
  properly.

* Define an osd_err_priority enum which divides the possible errors into
  7 categories in ascending severity. Each category is also assigned a
  Linux return code translation.

  Analyze the different osd/scsi/block returned errors and set the
  proper osd_err_priority and Linux return code accordingly.

* extra check a few situations so not to get stuck with inconsistent
  error view. Example an empty residual with an error code, and other
  places ...

Lots of libosd's osd_req_decode_sense clients had this logic in some
form or another. Consolidate all these into one place that should
actually know about osd returns. Thous translating it to a more
abstract error.

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] libosd: Bugfix of error handling in attributes-list decoding

2009-12-04T18:01:47+00:00

When an error was detected in an attribute list do to
a target bug. We would print an error but spin endlessly
regardless. Fix it.

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] libosd: bug in osd_req_decode_sense_full()

2009-12-04T18:01:46+00:00

The (never tested) osd_sense_attribute_identification case
has never worked. The loop was never advanced on.
Fix it to work as intended.

On 10/30/2009 04:39 PM, Roel Kluin wrote:
  I found this by code analysis, searching for while
  loops that test a local variable, but do not modify
  the variable.

Reported-by: Roel Kluin 
Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] libosd: osd_dev_info: Unique Identification of an OSD device

2009-12-04T18:01:46+00:00

Define an osd_dev_info structure that Uniquely identifies an OSD
device lun on the network. The identification is built from unique
target attributes and is the same for all network/SAN machines.

osduld_info_lookup() - NEW
    New API that will lookup an osd_dev by its osd_dev_info.
    This is used by pNFS-objects for cross network global device
    identification. And by exofs multy-device support, the device
    info is specified in the on-disk exofs device table.

osduld_device_info() - NEW
    Given an osd_dev handle returns its associated osd_dev_info.
    The ULD fetches this information at startup and hangs it on
    each OSD device. (This is a fast operation that can be called
    at any condition)

osduld_device_same() - NEW
    With a given osd_dev at one hand and an osd_dev_info
    at another, we would like to know if they are the same
    device.
    Two osd_dev handles can be checked by:
        osduld_device_same(od1, osduld_device_info(od2));

osd_auto_detect_ver() - REVISED
    Now returns an osd_dev_info structure. Is only called once
    by ULD as before. See added comments for how to use.

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] osduld: Use device->release instead of internal kref

2009-12-04T18:01:45+00:00

The true logic of this patch will be clear in the next patch where we
use the class_find_device() API. When doing so the use of an internal
kref leaves us a narrow window where a find is started while the actual
object can go away. Using the device's kobj reference solves this
problem because now the same kref is used for both operations. (Remove
and find)

Core changes
* Embed a struct device in uld_ structure and use device_register
  instead of devie_create. Set __remove to be the device release
  function.
* __uld_get/put is just get_/put_device. Now every thing is accounted
  for on the device object. Internal kref is removed.
* At __remove() we can safely de-allocate the uld_ structure. (The
  function has moved to avoid forward declaration)

Some cleanups
* Use class register/unregister is cleaner for this driver now.
* cdev ref-counting games are no longer necessary

I have incremented the device version string in case of new bugs.

Note: Previous bugfix of taking the reference around fput() still
      applies.

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] osduld: Ref-counting bug fix

2009-12-04T18:01:45+00:00

If scsi has released the device (logout), and exofs has last
reference on the osduld_device it will be freed by
osd_uld_release() within the call to fput(). But this will
oops in cdev_release() which is called after the fops->release.
(cdev is embedded within osduld_device). __uld_get/put pair
makes sure we have a cdev for the duration of fput()

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] Merge branch 'linus'

2009-06-12T15:02:03+00:00

Conflicts:
	drivers/message/fusion/mptsas.c

fixed up conflict between req->data_len accessors and mptsas driver updates.

Signed-off-by: James Bottomley

[SCSI] osd: Remove out-of-tree left overs

2009-06-10T14:00:41+00:00

* Delete Makefile. It is only used for out-of-tree compilation
  and was never needed. It slipped in by mistake.
* Remove from Kbuild all the out of tree stuff as promised.

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley

[SCSI] libosd: Use REQ_QUIET requests.

2009-06-10T14:00:32+00:00

libosd has it's own sense decoding and printout. Don't
let scsi_lib duplicate that printout. (Which is done wrong
in regard to osd commands)

Signed-off-by: Boaz Harrosh 
Signed-off-by: James Bottomley