[SCSI] zfcp: create private slab caches to guarantee proper data alignment

Create private slab caches in order to guarantee proper alignment of
data structures that get passed to hardware.

Sidenote: with this patch slab cache debugging will finally work on s390
(at least no known problems left).

Furthermore this patch does some minor cleanups:
- store ptr for transport template in struct zfcp_data

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Compile fix ups and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 22 insertions, 11 deletions

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index ff2eacf5ec8c..4913ffbb2fc8 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -100,14 +100,19 @@ zfcp_fsf_req_alloc(mempool_t *pool, int req_flags)
         if (req_flags & ZFCP_REQ_NO_QTCB)
                 size = sizeof(struct zfcp_fsf_req);
         else
-                size = sizeof(struct zfcp_fsf_req_pool_element);
+                size = sizeof(struct zfcp_fsf_req_qtcb);
 
-        if (likely(pool != NULL))
+        if (likely(pool))
                 ptr = mempool_alloc(pool, GFP_ATOMIC);
-        else
-                ptr = kmalloc(size, GFP_ATOMIC);
+        else {
+                if (req_flags & ZFCP_REQ_NO_QTCB)
+                        ptr = kmalloc(size, GFP_ATOMIC);
+                else
+                        ptr = kmem_cache_alloc(zfcp_data.fsf_req_qtcb_cache,
+                                               SLAB_ATOMIC);
+        }
 
-        if (unlikely(NULL == ptr))
+        if (unlikely(!ptr))
                 goto out;
 
         memset(ptr, 0, size);
@@ -115,9 +120,8 @@ zfcp_fsf_req_alloc(mempool_t *pool, int req_flags)
         if (req_flags & ZFCP_REQ_NO_QTCB) {
                 fsf_req = (struct zfcp_fsf_req *) ptr;
         } else {
-                fsf_req = &((struct zfcp_fsf_req_pool_element *) ptr)->fsf_req;
-                fsf_req->qtcb =
-                        &((struct zfcp_fsf_req_pool_element *) ptr)->qtcb;
+                fsf_req = &((struct zfcp_fsf_req_qtcb *) ptr)->fsf_req;
+                fsf_req->qtcb = &((struct zfcp_fsf_req_qtcb *) ptr)->qtcb;
         }
 
         fsf_req->pool = pool;
@@ -139,10 +143,17 @@ zfcp_fsf_req_alloc(mempool_t *pool, int req_flags)
 void
 zfcp_fsf_req_free(struct zfcp_fsf_req *fsf_req)
 {
-        if (likely(fsf_req->pool != NULL))
+        if (likely(fsf_req->pool)) {
                 mempool_free(fsf_req, fsf_req->pool);
-        else
-                kfree(fsf_req);
+                return;
+        }
+
+        if (fsf_req->qtcb) {
+                kmem_cache_free(zfcp_data.fsf_req_qtcb_cache, fsf_req);
+                return;
+        }
+
+        kfree(fsf_req);
 }
 
 /**