ANDROID: dm: mount as linear target if eng build

eng builds dont have verity enabled i.e it does even
have verity metadata appended to the parition. Therefore
add rootdev as linear device and map the entire partition
if build variant is "eng".

(Cherry-picked based on
https://partner-android-review.git.corp.google.com/#/c/618690/)

BUG: 29276559
Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
Change-Id: I8f5c2289b842b820ca04f5773525e5449bb3f355
Git-commit: 58bae772a7
Git-repo: https://android.googlesource.com/kernel/common
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>

drivers/md/dm-android-verity.c

@@ -44,6 +44,7 @@
 static char verifiedbootstate[VERITY_COMMANDLINE_PARAM_LENGTH];
 static char veritymode[VERITY_COMMANDLINE_PARAM_LENGTH];
 static char veritykeyid[VERITY_DEFAULT_KEY_ID_LENGTH];
+static char buildvariant[BUILD_VARIANT];
 
 static bool target_added;
 static bool verity_enabled = true;
@@ -88,11 +89,26 @@ static int __init verity_keyid_param(char *line)
 
 __setup("veritykeyid=", verity_keyid_param);
 
+static int __init verity_buildvariant(char *line)
+{
+	strlcpy(buildvariant, line, sizeof(buildvariant));
+	return 1;
+}
+
+__setup("buildvariant=", verity_buildvariant);
+
 static inline bool default_verity_key_id(void)
 {
 	return veritykeyid[0] != '\0';
 }
 
+static inline bool is_eng(void)
+{
+	static const char typeeng[]  = "eng";
+
+	return !strncmp(buildvariant, typeeng, sizeof(typeeng));
+}
+
 static int table_extract_mpi_array(struct public_key_signature *pks,
 				const void *data, size_t len)
 {
@@ -262,7 +278,7 @@ static int extract_fec_header(dev_t dev, struct fec_header *fec,
 
 	bdev = blkdev_get_by_dev(dev, FMODE_READ, NULL);
 
-	if (IS_ERR(bdev)) {
+	if (IS_ERR_OR_NULL(bdev)) {
 		DMERR("bdev get error");
 		return PTR_ERR(bdev);
 	}
@@ -323,6 +339,24 @@ static void find_metadata_offset(struct fec_header *fec,
 		*metadata_offset = device_size - VERITY_METADATA_SIZE;
 }
 
+static int find_size(dev_t dev, u64 *device_size)
+{
+	struct block_device *bdev;
+
+	bdev = blkdev_get_by_dev(dev, FMODE_READ, NULL);
+	if (IS_ERR_OR_NULL(bdev)) {
+		DMERR("blkdev_get_by_dev failed");
+		return PTR_ERR(bdev);
+	}
+
+	*device_size = i_size_read(bdev->bd_inode);
+	*device_size >>= SECTOR_SHIFT;
+
+	DMINFO("blkdev size in sectors: %llu", *device_size);
+	blkdev_put(bdev, FMODE_READ);
+	return 0;
+}
+
 static struct android_metadata *extract_metadata(dev_t dev,
 				struct fec_header *fec)
 {
@@ -337,7 +371,7 @@ static struct android_metadata *extract_metadata(dev_t dev,
 
 	bdev = blkdev_get_by_dev(dev, FMODE_READ, NULL);
 
-	if (IS_ERR(bdev)) {
+	if (IS_ERR_OR_NULL(bdev)) {
 		DMERR("blkdev_get_by_dev failed");
 		return ERR_CAST(bdev);
 	}
@@ -632,12 +666,13 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	struct fec_ecc_metadata uninitialized_var(ecc);
 	char buf[FEC_ARG_LENGTH], *buf_ptr;
 	unsigned long long tmpll;
+	u64 device_size;
 
 	if (argc == 1) {
 		/* Use the default keyid */
 		if (default_verity_key_id())
 			key_id = veritykeyid;
-		else {
+		else if (!is_eng()) {
 			DMERR("veritykeyid= is not set");
 			handle_error();
 			return -EINVAL;
@@ -650,7 +685,6 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		return -EINVAL;
 	}
 
-	strreplace(key_id, '#', ' ');
 	target_device = argv[0];
 
 	dev = name_to_dev_t(target_device);
@@ -660,6 +694,26 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		return -EINVAL;
 	}
 
+	if (is_eng()) {
+		err = find_size(dev, &device_size);
+		if (err) {
+			DMERR("error finding bdev size");
+			handle_error();
+			return err;
+		}
+
+		ti->len = device_size;
+		err = add_as_linear_device(ti, target_device);
+		if (err) {
+			handle_error();
+			return err;
+		}
+		verity_enabled = false;
+		return 0;
+	}
+
+	strreplace(key_id, '#', ' ');
+
 	DMINFO("key:%s dev:%s", key_id, target_device);
 
 	if (extract_fec_header(dev, &fec, &ecc)) {

drivers/md/dm-android-verity.h

@@ -26,6 +26,7 @@
 #define VERITY_METADATA_SIZE (8 * DATA_BLOCK_SIZE)
 #define VERITY_TABLE_ARGS 10
 #define VERITY_COMMANDLINE_PARAM_LENGTH 20
+#define BUILD_VARIANT 20
 
 /*
  * <subject>:<sha1-id> is the format for the identifier.