From b2e3a83da4f91c040da62e6ca1ef3c8f8ab15553 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Thu, 12 Feb 2009 10:40:05 +0000
Subject: [PATCH] --- yaml --- r: 142319 b: refs/heads/master c:
 6e232cfce35a20a8702d9ac7709d35030c1b3271 h: refs/heads/master i:   142317:
 045c472f5521da49f0d616cc88100d8e84c76ded   142315:
 6ec693fbd7c5240ab7841d8c09c7807c08f4550b   142311:
 0ba8eebc0d7d30d99c274c681817c9a166e27e1b   142303:
 ee8de63b68eb25cd4af9272a0cc99a162036e38e v: v3

---
 [refs]                        |  2 +-
 trunk/drivers/mtd/mtdconcat.c | 47 +++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index a8e766fa736b..0267b84fe75f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 402d326519c1a4859c527702383f4e60f606ef52
+refs/heads/master: 6e232cfce35a20a8702d9ac7709d35030c1b3271
diff --git a/trunk/drivers/mtd/mtdconcat.c b/trunk/drivers/mtd/mtdconcat.c
index 3dbb1b38db66..792b547786b8 100644
--- a/trunk/drivers/mtd/mtdconcat.c
+++ b/trunk/drivers/mtd/mtdconcat.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/types.h>
+#include <linux/backing-dev.h>
 
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/concat.h>
@@ -683,6 +684,40 @@ static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 	return err;
 }
 
+/*
+ * try to support NOMMU mmaps on concatenated devices
+ * - we don't support subdev spanning as we can't guarantee it'll work
+ */
+static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
+					      unsigned long len,
+					      unsigned long offset,
+					      unsigned long flags)
+{
+	struct mtd_concat *concat = CONCAT(mtd);
+	int i;
+
+	for (i = 0; i < concat->num_subdev; i++) {
+		struct mtd_info *subdev = concat->subdev[i];
+
+		if (offset >= subdev->size) {
+			offset -= subdev->size;
+			continue;
+		}
+
+		/* we've found the subdev over which the mapping will reside */
+		if (offset + len > subdev->size)
+			return (unsigned long) -EINVAL;
+
+		if (subdev->get_unmapped_area)
+			return subdev->get_unmapped_area(subdev, len, offset,
+							 flags);
+
+		break;
+	}
+
+	return (unsigned long) -ENOSYS;
+}
+
 /*
  * This function constructs a virtual MTD device by concatenating
  * num_devs MTD devices. A pointer to the new device object is
@@ -740,6 +775,8 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 
 	concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 
+	concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
+
 	concat->subdev[0] = subdev[0];
 
 	for (i = 1; i < num_devs; i++) {
@@ -766,6 +803,15 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 				concat->mtd.flags |=
 				    subdev[i]->flags & MTD_WRITEABLE;
 		}
+
+		/* only permit direct mapping if the BDIs are all the same
+		 * - copy-mapping is still permitted
+		 */
+		if (concat->mtd.backing_dev_info !=
+		    subdev[i]->backing_dev_info)
+			concat->mtd.backing_dev_info =
+				&default_backing_dev_info;
+
 		concat->mtd.size += subdev[i]->size;
 		concat->mtd.ecc_stats.badblocks +=
 			subdev[i]->ecc_stats.badblocks;
@@ -796,6 +842,7 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 	concat->mtd.unlock = concat_unlock;
 	concat->mtd.suspend = concat_suspend;
 	concat->mtd.resume = concat_resume;
+	concat->mtd.get_unmapped_area = concat_get_unmapped_area;
 
 	/*
 	 * Combine the erase block size info of the subdevices: