[SCSI] mpt2sas: Calulate the Reply post queue depth calculation as per the MPI spec

[jejb: checkpatch fixes]
Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 14 insertions, 12 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c b/drivers/scsi/mpt2sas/mpt2sas_base.c
index 8bb1fe96f21e..ccd6d5a97ec3 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.c
@@ -2503,23 +2503,25 @@ _base_allocate_memory_pools(struct MPT2SAS_ADAPTER *ioc,  int sleep_flag)
         /* reply free queue sizing - taking into account for 64 FW events */
         ioc->reply_free_queue_depth = ioc->hba_queue_depth + 64;
 
+        /* calculate reply descriptor post queue depth */
+        ioc->reply_post_queue_depth = ioc->hba_queue_depth +
+                                        ioc->reply_free_queue_depth +  1;
         /* align the reply post queue on the next 16 count boundary */
-        if (!ioc->reply_free_queue_depth % 16)
-                ioc->reply_post_queue_depth = ioc->reply_free_queue_depth + 16;
-        else
-                ioc->reply_post_queue_depth = ioc->reply_free_queue_depth +
-                                32 - (ioc->reply_free_queue_depth % 16);
+        if (ioc->reply_post_queue_depth % 16)
+                ioc->reply_post_queue_depth += 16 -
+                        (ioc->reply_post_queue_depth % 16);
+
+
         if (ioc->reply_post_queue_depth >
             facts->MaxReplyDescriptorPostQueueDepth) {
-                ioc->reply_post_queue_depth = min_t(u16,
-                    (facts->MaxReplyDescriptorPostQueueDepth -
-                    (facts->MaxReplyDescriptorPostQueueDepth % 16)),
-                    (ioc->hba_queue_depth - (ioc->hba_queue_depth % 16)));
-                ioc->reply_free_queue_depth = ioc->reply_post_queue_depth - 16;
-                ioc->hba_queue_depth = ioc->reply_free_queue_depth - 64;
+                ioc->reply_post_queue_depth =
+                        facts->MaxReplyDescriptorPostQueueDepth -
+                    (facts->MaxReplyDescriptorPostQueueDepth % 16);
+                ioc->hba_queue_depth =
+                        ((ioc->reply_post_queue_depth - 64) / 2) - 1;
+                ioc->reply_free_queue_depth = ioc->hba_queue_depth + 64;
         }
 
-
         dinitprintk(ioc, printk(MPT2SAS_INFO_FMT "scatter gather: "
             "sge_in_main_msg(%d), sge_per_chain(%d), sge_per_io(%d), "
             "chains_per_io(%d)\n", ioc->name, ioc->max_sges_in_main_message,