[PATCH] i2o: block IO errors on i2o disk

I2O subsystem has been broken in mainstream several months ago (after
2.6.18).  Commit 4aff5e2333c9a1609662f2091f55c3f6fffdad36 from Jens
Axboe split struct request ->flags into two parts: cmd_type and
cmd_flags.

In i2o layer this patch has replaced flag REQ_SPECIAL by the according
cmd_type.  However i2o has used REQ_SPECIAL not as command type but as
driver-specific flag for the debug purposes.  As result all i2o requests
have type "special" now, are not processed to the hardware and fail with
I/O error:

   i2o/hda:<3>Buffer I/O error on device i2o/hda, logical block 0
  Buffer I/O error on device i2o/hda, logical block 0
  Buffer I/O error on device i2o/hda, logical block 0
   unable to read partition table
  block-osm: device added (TID: 207): i2o/hda

The following patch removes the extra debug checks without any drawbacks and
restores the normal driver's work.

Signed-off-by:	Vasily Averin <vvs@sw.ru>
Acked-by: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 11 deletions

diff --git a/drivers/message/i2o/i2o_block.c b/drivers/message/i2o/i2o_block.c
index da9859f2caf2..b17c4b2bc9ef 100644
--- a/drivers/message/i2o/i2o_block.c
+++ b/drivers/message/i2o/i2o_block.c
@@ -390,13 +390,6 @@ static int i2o_block_prep_req_fn(struct request_queue *q, struct request *req)
                 return BLKPREP_KILL;
         }
 
-        /* request is already processed by us, so return */
-        if (blk_special_request(req)) {
-                osm_debug("REQ_SPECIAL already set!\n");
-                req->cmd_flags |= REQ_DONTPREP;
-                return BLKPREP_OK;
-        }
-
         /* connect the i2o_block_request to the request */
         if (!req->special) {
                 ireq = i2o_block_request_alloc();
@@ -408,11 +401,8 @@ static int i2o_block_prep_req_fn(struct request_queue *q, struct request *req)
                 ireq->i2o_blk_dev = i2o_blk_dev;
                 req->special = ireq;
                 ireq->req = req;
-        } else
-                ireq = req->special;
-
+        }
         /* do not come back here */
-        req->cmd_type = REQ_TYPE_SPECIAL;
         req->cmd_flags |= REQ_DONTPREP;
 
         return BLKPREP_OK;