1 files changed, 23 insertions, 10 deletions

diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 6e4d0017c0bd..f685a581df48 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -641,6 +641,7 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 	int i;
 	size_t size;
 	struct mtd_concat *concat;
+	struct mtd_info *subdev_master = NULL;
 	uint32_t max_erasesize, curr_erasesize;
 	int num_erase_region;
 	int max_writebufsize = 0;
@@ -679,18 +680,24 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 	concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 	concat->mtd.oobsize = subdev[0]->oobsize;
 	concat->mtd.oobavail = subdev[0]->oobavail;
-	if (subdev[0]->_writev)
+
+	subdev_master = mtd_get_master(subdev[0]);
+	if (subdev_master->_writev)
 		concat->mtd._writev = concat_writev;
-	if (subdev[0]->_read_oob)
+	if (subdev_master->_read_oob)
 		concat->mtd._read_oob = concat_read_oob;
-	if (subdev[0]->_write_oob)
+	if (subdev_master->_write_oob)
 		concat->mtd._write_oob = concat_write_oob;
-	if (subdev[0]->_block_isbad)
+	if (subdev_master->_block_isbad)
 		concat->mtd._block_isbad = concat_block_isbad;
-	if (subdev[0]->_block_markbad)
+	if (subdev_master->_block_markbad)
 		concat->mtd._block_markbad = concat_block_markbad;
-	if (subdev[0]->_panic_write)
+	if (subdev_master->_panic_write)
 		concat->mtd._panic_write = concat_panic_write;
+	if (subdev_master->_read)
+		concat->mtd._read = concat_read;
+	if (subdev_master->_write)
+		concat->mtd._write = concat_write;
 
 	concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 
@@ -721,14 +728,22 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 				    subdev[i]->flags & MTD_WRITEABLE;
 		}
 
+		subdev_master = mtd_get_master(subdev[i]);
 		concat->mtd.size += subdev[i]->size;
 		concat->mtd.ecc_stats.badblocks +=
 			subdev[i]->ecc_stats.badblocks;
 		if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 		    concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 		    concat->mtd.oobsize    !=  subdev[i]->oobsize ||
-		    !concat->mtd._read_oob  != !subdev[i]->_read_oob ||
-		    !concat->mtd._write_oob != !subdev[i]->_write_oob) {
+		    !concat->mtd._read_oob  != !subdev_master->_read_oob ||
+		    !concat->mtd._write_oob != !subdev_master->_write_oob) {
+			/*
+			 * Check against subdev[i] for data members, because
+			 * subdev's attributes may be different from master
+			 * mtd device. Check against subdev's master mtd
+			 * device for callbacks, because the existence of
+			 * subdev's callbacks is decided by master mtd device.
+			 */
 			kfree(concat);
 			printk("Incompatible OOB or ECC data on \"%s\"\n",
 			       subdev[i]->name);
@@ -744,8 +759,6 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 	concat->mtd.name = name;
 
 	concat->mtd._erase = concat_erase;
-	concat->mtd._read = concat_read;
-	concat->mtd._write = concat_write;
 	concat->mtd._sync = concat_sync;
 	concat->mtd._lock = concat_lock;
 	concat->mtd._unlock = concat_unlock;