Nov 23 2012

UBI: replace memcpy with struct assignment 

Author: Ezequiel Garcia <elezegarcia@gmail.com>

This kind of memcpy() is error-prone. Its replacement with a struct
assignment is prefered because it's type-safe and much easier to read.

Found by coccinelle. Hand patched and reviewed.
Tested by compilation only.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@@
identifier struct_name;
struct struct_name to;
struct struct_name from;
expression E;
@@
-memcpy(&(to), &(from), E);
+to = from;
// 

Signed-off-by: Peter Senna Tschudin 
Signed-off-by: Ezequiel Garcia 
Signed-off-by: Artem Bityutskiy 

---
 drivers/mtd/ubi/build.c | 3 +--
 drivers/mtd/ubi/upd.c   | 6 ++----
 drivers/mtd/ubi/vmt.c   | 2 +-
 3 files changed, 4 insertions(+), 7 deletions(-)
 
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 344b4cb..fb59604 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -825,8 +825,7 @@ static int autoresize(struct ubi_device *ubi, int vol_id)
 		 * No available PEBs to re-size the volume, clear the flag on
 		 * flash and exit.
 		 */
-		memcpy(&vtbl_rec, &ubi->vtbl[vol_id],
-		       sizeof(struct ubi_vtbl_record));
+		vtbl_rec = ubi->vtbl[vol_id];
 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
 		if (err)
 			ubi_err("cannot clean auto-resize flag for volume %d",
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 9f2ebd8..ec2c2dc 100644
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -64,8 +64,7 @@ static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol)
 		return 0;
 	}
 
-	memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
-	       sizeof(struct ubi_vtbl_record));
+	vtbl_rec = ubi->vtbl[vol->vol_id];
 	vtbl_rec.upd_marker = 1;
 
 	mutex_lock(&ubi->device_mutex);
@@ -93,8 +92,7 @@ static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
 
 	dbg_gen("clear update marker for volume %d", vol->vol_id);
 
-	memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
-	       sizeof(struct ubi_vtbl_record));
+	vtbl_rec = ubi->vtbl[vol->vol_id];
 	ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
 	vtbl_rec.upd_marker = 0;
 
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 9169e58..99ef8a1 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -535,7 +535,7 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
 	}
 
 	/* Change volume table record */
-	memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
+	vtbl_rec = ubi->vtbl[vol_id];
 	vtbl_rec.reserved_pebs = cpu_to_be32(reserved_pebs);
 	err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
 	if (err)

qlambert