[SCSI] seperate max_sectors from max_hw_sectors

- export __blk_put_request and blk_execute_rq_nowait
needed for async REQ_BLOCK_PC requests
- seperate max_hw_sectors and max_sectors for block/scsi_ioctl.c and
SG_IO bio.c helpers per Jens's last comments. Since block/scsi_ioctl.c SG_IO was
already testing against max_sectors and SCSI-ml was setting max_sectors and
max_hw_sectors to the same value this does not change any scsi SG_IO behavior. It only
prepares ll_rw_blk.c, scsi_ioctl.c and bio.c for when SCSI-ml begins to set
a valid max_hw_sectors for all LLDs. Today if a LLD does not set it
SCSI-ml sets it to a safe default and some LLDs set it to a artificial low
value to overcome memory and feedback issues.

Note: Since we now cap max_sectors to BLK_DEF_MAX_SECTORS, which is 1024,
drivers that used to call blk_queue_max_sectors with a large value of
max_sectors will now see the fs requests capped to BLK_DEF_MAX_SECTORS.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index a6d3baa46f61..a6f2dc66c3db 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -638,7 +638,7 @@ int dm_split_args(int *argc, char ***argvp, char *input)
 static void check_for_valid_limits(struct io_restrictions *rs)
 {
         if (!rs->max_sectors)
-                rs->max_sectors = MAX_SECTORS;
+                rs->max_sectors = SAFE_MAX_SECTORS;
         if (!rs->max_phys_segments)
                 rs->max_phys_segments = MAX_PHYS_SEGMENTS;
         if (!rs->max_hw_segments)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 54a72f197487..14ad2a785a34 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -462,6 +462,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
         req = blk_get_request(sdev->request_queue, write, gfp);
         if (!req)
                 goto free_sense;
+        req->flags |= REQ_BLOCK_PC | REQ_QUIET;
 
         if (use_sg)
                 err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
@@ -477,7 +478,6 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
         req->sense_len = 0;
         req->timeout = timeout;
         req->retries = retries;
-        req->flags |= REQ_BLOCK_PC | REQ_QUIET;
         req->end_io_data = sioc;
 
         sioc->data = privdata;