s390/cio: use kmem_cache for extended measurement block allocation

Extended measurement blocks need to be 64 byte aligned. To achieve that
128 bytes for each measurement block are allocated and an align callback
returns a 64 byte aligned address inside this area.

Replace this code with kmem_cache allocations.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/cmf.c

@@ -113,7 +113,6 @@ module_param(format, bint, 0444);
  * @readall:	read a measurement block in a common format
  * @reset:	clear the data in the associated measurement block and
  *		reset its time stamp
- * @align:	align an allocated block so that the hardware can use it
  */
 struct cmb_operations {
 	int  (*alloc)  (struct ccw_device *);
@@ -122,7 +121,6 @@ struct cmb_operations {
 	u64  (*read)   (struct ccw_device *, int);
 	int  (*readall)(struct ccw_device *, struct cmbdata *);
 	void (*reset)  (struct ccw_device *);
-	void *(*align) (void *);
 /* private: */
 	struct attribute_group *attr_group;
 };
@@ -321,7 +319,7 @@ static int cmf_copy_block(struct ccw_device *cdev)
 			return -EBUSY;
 	}
 	cmb_data = cdev->private->cmb;
-	hw_block = cmbops->align(cmb_data->hw_block);
+	hw_block = cmb_data->hw_block;
 	if (!memcmp(cmb_data->last_block, hw_block, cmb_data->size))
 		/* No need to copy. */
 		return 0;
@@ -432,7 +430,7 @@ static void cmf_generic_reset(struct ccw_device *cdev)
 		 * Need to reset hw block as well to make the hardware start
 		 * from 0 again.
 		 */
-		memset(cmbops->align(cmb_data->hw_block), 0, cmb_data->size);
+		memset(cmb_data->hw_block, 0, cmb_data->size);
 		cmb_data->last_update = 0;
 	}
 	cdev->private->cmb_start_time = get_tod_clock();
@@ -755,11 +753,6 @@ static void reset_cmb(struct ccw_device *cdev)
 	cmf_generic_reset(cdev);
 }
 
-static void * align_cmb(void *area)
-{
-	return area;
-}
-
 static struct attribute_group cmf_attr_group;
 
 static struct cmb_operations cmbops_basic = {
@@ -769,7 +762,6 @@ static struct cmb_operations cmbops_basic = {
 	.read	= read_cmb,
 	.readall    = readall_cmb,
 	.reset	    = reset_cmb,
-	.align	    = align_cmb,
 	.attr_group = &cmf_attr_group,
 };
 
@@ -804,20 +796,9 @@ struct cmbe {
 	u32 device_busy_time;
 	u32 initial_command_response_time;
 	u32 reserved[7];
-};
+} __packed __aligned(64);
 
-/*
- * kmalloc only guarantees 8 byte alignment, but we need cmbe
- * pointers to be naturally aligned. Make sure to allocate
- * enough space for two cmbes.
- */
-static inline struct cmbe *cmbe_align(struct cmbe *c)
-{
-	unsigned long addr;
-	addr = ((unsigned long)c + sizeof (struct cmbe) - sizeof(long)) &
-				 ~(sizeof (struct cmbe) - sizeof(long));
-	return (struct cmbe*)addr;
-}
+static struct kmem_cache *cmbe_cache;
 
 static int alloc_cmbe(struct ccw_device *cdev)
 {
@@ -825,11 +806,11 @@ static int alloc_cmbe(struct ccw_device *cdev)
 	struct cmbe *cmbe;
 	int ret = -ENOMEM;
 
-	cmbe = kzalloc (sizeof (*cmbe) * 2, GFP_KERNEL);
+	cmbe = kmem_cache_zalloc(cmbe_cache, GFP_KERNEL);
 	if (!cmbe)
 		return ret;
 
-	cmb_data = kzalloc(sizeof(struct cmb_data), GFP_KERNEL);
+	cmb_data = kzalloc(sizeof(*cmb_data), GFP_KERNEL);
 	if (!cmb_data)
 		goto out_free;
 
@@ -837,7 +818,7 @@ static int alloc_cmbe(struct ccw_device *cdev)
 	if (!cmb_data->last_block)
 		goto out_free;
 
-	cmb_data->size = sizeof(struct cmbe);
+	cmb_data->size = sizeof(*cmbe);
 	cmb_data->hw_block = cmbe;
 
 	spin_lock(&cmb_area.lock);
@@ -864,7 +845,8 @@ out_free:
 	if (cmb_data)
 		kfree(cmb_data->last_block);
 	kfree(cmb_data);
-	kfree(cmbe);
+	kmem_cache_free(cmbe_cache, cmbe);
+
 	return ret;
 }
 
@@ -878,7 +860,7 @@ static void free_cmbe(struct ccw_device *cdev)
 	cdev->private->cmb = NULL;
 	if (cmb_data) {
 		kfree(cmb_data->last_block);
-		kfree(cmb_data->hw_block);
+		kmem_cache_free(cmbe_cache, cmb_data->hw_block);
 	}
 	kfree(cmb_data);
 
@@ -902,7 +884,7 @@ static int set_cmbe(struct ccw_device *cdev, u32 mme)
 		return -EINVAL;
 	}
 	cmb_data = cdev->private->cmb;
-	mba = mme ? (unsigned long) cmbe_align(cmb_data->hw_block) : 0;
+	mba = mme ? (unsigned long) cmb_data->hw_block : 0;
 	spin_unlock_irqrestore(cdev->ccwlock, flags);
 
 	return set_schib_wait(cdev, mme, 1, mba);
@@ -1027,11 +1009,6 @@ static void reset_cmbe(struct ccw_device *cdev)
 	cmf_generic_reset(cdev);
 }
 
-static void * align_cmbe(void *area)
-{
-	return cmbe_align(area);
-}
-
 static struct attribute_group cmf_attr_group_ext;
 
 static struct cmb_operations cmbops_extended = {
@@ -1041,7 +1018,6 @@ static struct cmb_operations cmbops_extended = {
 	.read	    = read_cmbe,
 	.readall    = readall_cmbe,
 	.reset	    = reset_cmbe,
-	.align	    = align_cmbe,
 	.attr_group = &cmf_attr_group_ext,
 };
 
@@ -1336,10 +1312,19 @@ int cmf_reenable(struct ccw_device *cdev)
 	return cmbops->set(cdev, 2);
 }
 
+static int __init init_cmbe(void)
+{
+	cmbe_cache = kmem_cache_create("cmbe_cache", sizeof(struct cmbe),
+				       __alignof__(struct cmbe), 0, NULL);
+
+	return cmbe_cache ? 0 : -ENOMEM;
+}
+
 static int __init init_cmf(void)
 {
 	char *format_string;
-	char *detect_string = "parameter";
+	char *detect_string;
+	int ret;
 
 	/*
 	 * If the user did not give a parameter, see if we are running on a
@@ -1365,15 +1350,18 @@ static int __init init_cmf(void)
 	case CMF_EXTENDED:
 		format_string = "extended";
 		cmbops = &cmbops_extended;
+
+		ret = init_cmbe();
+		if (ret)
+			return ret;
 		break;
 	default:
-		return 1;
+		return -EINVAL;
 	}
 	pr_info("Channel measurement facility initialized using format "
 		"%s (mode %s)\n", format_string, detect_string);
 	return 0;
 }
-
 module_init(init_cmf);