s390/cio: fix measurement characteristics memleak

BugLink: http://bugs.launchpad.net/bugs/1541534

Measurement characteristics are allocated during channel path
registration but not freed during deregistration. Fix this by
embedding these characteristics inside struct channel_path.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
(cherry picked from commit 0d9bfe91)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/s390/cio/chp.c

@@ -139,11 +139,11 @@ static ssize_t chp_measurement_chars_read(struct file *filp,
 
 	device = container_of(kobj, struct device, kobj);
 	chp = to_channelpath(device);
-	if (!chp->cmg_chars)
+	if (chp->cmg == -1)
 		return 0;
 
-	return memory_read_from_buffer(buf, count, &off,
-				chp->cmg_chars, sizeof(struct cmg_chars));
+	return memory_read_from_buffer(buf, count, &off, &chp->cmg_chars,
+				       sizeof(chp->cmg_chars));
 }
 
 static struct bin_attribute chp_measurement_chars_attr = {

drivers/s390/cio/chp.h

@@ -48,7 +48,7 @@ struct channel_path {
 	/* Channel-measurement related stuff: */
 	int cmg;
 	int shared;
-	void *cmg_chars;
+	struct cmg_chars cmg_chars;
 };
 
 /* Return channel_path struct for given chpid. */

drivers/s390/cio/chsc.c

@@ -967,22 +967,19 @@ static void
 chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,
 			  struct cmg_chars *chars)
 {
-	struct cmg_chars *cmg_chars;
 	int i, mask;
 
-	cmg_chars = chp->cmg_chars;
 	for (i = 0; i < NR_MEASUREMENT_CHARS; i++) {
 		mask = 0x80 >> (i + 3);
 		if (cmcv & mask)
-			cmg_chars->values[i] = chars->values[i];
+			chp->cmg_chars.values[i] = chars->values[i];
 		else
-			cmg_chars->values[i] = 0;
+			chp->cmg_chars.values[i] = 0;
 	}
 }
 
 int chsc_get_channel_measurement_chars(struct channel_path *chp)
 {
-	struct cmg_chars *cmg_chars;
 	int ccode, ret;
 
 	struct {
@@ -1006,11 +1003,6 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 		u32 data[NR_MEASUREMENT_CHARS];
 	} __attribute__ ((packed)) *scmc_area;
 
-	chp->cmg_chars = NULL;
-	cmg_chars = kmalloc(sizeof(*cmg_chars), GFP_KERNEL);
-	if (!cmg_chars)
-		return -ENOMEM;
-
 	spin_lock_irq(&chsc_page_lock);
 	memset(chsc_page, 0, PAGE_SIZE);
 	scmc_area = chsc_page;
@@ -1042,14 +1034,10 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 		/* No cmg-dependent data. */
 		goto out;
 	}
-	chp->cmg_chars = cmg_chars;
 	chsc_initialize_cmg_chars(chp, scmc_area->cmcv,
 				  (struct cmg_chars *) &scmc_area->data);
 out:
 	spin_unlock_irq(&chsc_page_lock);
-	if (!chp->cmg_chars)
-		kfree(cmg_chars);
-
 	return ret;
 }