dm vdo: use block_device already opened by VDO target in indexerdm-vdo.v3-with-bdev-changes-aka-v4

Remove indexer's name-based configuration management in favor of just
using the VDO target's already opened block_device struct (via
dm_dev).

Avoids needless complications due to needless memory allocation, etc.
But also removes io-factory.c's extraneous blkdev_get_by* calls.

FIXME: this must be folded into the baseline VDO patchset because
there have been quite a few changes to block core's bdev open
functions (and more are coming in Linux 6.7).

Signed-off-by: Mike Snitzer <snitzer@kernel.org>

13 files changed, 48 insertions, 137 deletions

diff --git a/drivers/md/dm-vdo/config.c b/drivers/md/dm-vdo/config.c
index 18ec44faf0b0b3..6a89f029dc21c1 100644
--- a/drivers/md/dm-vdo/config.c
+++ b/drivers/md/dm-vdo/config.c
@@ -357,7 +357,7 @@ int uds_make_configuration(const struct uds_parameters *params, struct configura
 	config->volume_index_mean_delta = DEFAULT_VOLUME_INDEX_MEAN_DELTA;
 	config->sparse_sample_rate = (params->sparse ? DEFAULT_SPARSE_SAMPLE_RATE : 0);
 	config->nonce = params->nonce;
-	config->name = params->name;
+	config->bdev = params->bdev;
 	config->offset = params->offset;
 	config->size = params->size;
 
diff --git a/drivers/md/dm-vdo/config.h b/drivers/md/dm-vdo/config.h
index d5120412b885fb..de23f5470f9c2d 100644
--- a/drivers/md/dm-vdo/config.h
+++ b/drivers/md/dm-vdo/config.h
@@ -25,8 +25,8 @@ enum {
 
 /* A set of configuration parameters for the indexer. */
 struct configuration {
-	/* String describing the storage device */
-	const char *name;
+	/* block_device of the index */
+	struct block_device *bdev;
 
 	/* The maximum allowable size of the index */
 	size_t size;
diff --git a/drivers/md/dm-vdo/dedupe.c b/drivers/md/dm-vdo/dedupe.c
index cddfa329230678..a6546a90312091 100644
--- a/drivers/md/dm-vdo/dedupe.c
+++ b/drivers/md/dm-vdo/dedupe.c
@@ -2233,7 +2233,7 @@ static int initialize_index(struct vdo *vdo, struct hash_zones *zones)
 	uds_offset = ((vdo_get_index_region_start(geometry) -
 		       geometry.bio_offset) * VDO_BLOCK_SIZE);
 	zones->parameters = (struct uds_parameters) {
-		.name = vdo->device_config->parent_device_name,
+		.bdev = vdo->device_config->owned_device->bdev,
 		.offset = uds_offset,
 		.size = (vdo_get_index_region_size(geometry) * VDO_BLOCK_SIZE),
 		.memory_size = geometry.index_config.mem,
@@ -2642,8 +2642,8 @@ static void resume_index(void *context, struct vdo_completion *parent)
 	struct device_config *config = parent->vdo->device_config;
 	int result;
 
-	zones->parameters.name = config->parent_device_name;
-	result = uds_resume_index_session(zones->index_session, zones->parameters.name);
+	zones->parameters.bdev = config->owned_device->bdev;
+	result = uds_resume_index_session(zones->index_session, zones->parameters.bdev);
 	if (result != UDS_SUCCESS)
 		uds_log_error_strerror(result, "Error resuming dedupe index");
 
diff --git a/drivers/md/dm-vdo/index-layout.c b/drivers/md/dm-vdo/index-layout.c
index ead2dcbbd58e54..a3bd56e3ef2d97 100644
--- a/drivers/md/dm-vdo/index-layout.c
+++ b/drivers/md/dm-vdo/index-layout.c
@@ -1677,7 +1677,7 @@ static int create_layout_factory(struct index_layout *layout, const struct confi
 	size_t writable_size;
 	struct io_factory *factory = NULL;
 
-	result = uds_make_io_factory(config->name, &factory);
+	result = uds_make_io_factory(config->bdev, &factory);
 	if (result != UDS_SUCCESS)
 		return result;
 
@@ -1751,9 +1751,9 @@ void uds_free_index_layout(struct index_layout *layout)
 	UDS_FREE(layout);
 }
 
-int uds_replace_index_layout_storage(struct index_layout *layout, const char *name)
+int uds_replace_index_layout_storage(struct index_layout *layout, struct block_device *bdev)
 {
-	return uds_replace_storage(layout->factory, name);
+	return uds_replace_storage(layout->factory, bdev);
 }
 
 /* Obtain a dm_bufio_client for the volume region. */
diff --git a/drivers/md/dm-vdo/index-layout.h b/drivers/md/dm-vdo/index-layout.h
index 2128e3826f7809..2a32c0bcb00bdd 100644
--- a/drivers/md/dm-vdo/index-layout.h
+++ b/drivers/md/dm-vdo/index-layout.h
@@ -24,7 +24,8 @@ int __must_check uds_make_index_layout(struct configuration *config,
 
 void uds_free_index_layout(struct index_layout *layout);
 
-int __must_check uds_replace_index_layout_storage(struct index_layout *layout, const char *name);
+int __must_check uds_replace_index_layout_storage(struct index_layout *layout,
+						  struct block_device *bdev);
 
 int __must_check uds_load_index_state(struct index_layout *layout, struct uds_index *index);
 
diff --git a/drivers/md/dm-vdo/index-session.c b/drivers/md/dm-vdo/index-session.c
index 333de13d15994c..f635341bbf0398 100644
--- a/drivers/md/dm-vdo/index-session.c
+++ b/drivers/md/dm-vdo/index-session.c
@@ -356,13 +356,14 @@ int uds_open_index(enum uds_open_index_type open_type,
 		   struct uds_index_session *session)
 {
 	int result;
+	char name[BDEVNAME_SIZE];
 
 	if (parameters == NULL) {
 		uds_log_error("missing required parameters");
 		return -EINVAL;
 	}
-	if (parameters->name == NULL) {
-		uds_log_error("missing required index name");
+	if (parameters->bdev == NULL) {
+		uds_log_error("missing required index bdev");
 		return -EINVAL;
 	}
 	if (session == NULL) {
@@ -374,27 +375,10 @@ int uds_open_index(enum uds_open_index_type open_type,
 	if (result != UDS_SUCCESS)
 		return uds_map_to_system_error(result);
 
-	if ((session->parameters.name == NULL) ||
-	    (strcmp(parameters->name, session->parameters.name) != 0)) {
-		char *new_name;
+	session->parameters = *parameters;
 
-		result = uds_duplicate_string(parameters->name, "device name", &new_name);
-		if (result != UDS_SUCCESS) {
-			finish_loading_index_session(session, result);
-			return uds_map_to_system_error(result);
-		}
-
-		uds_free_const(session->parameters.name);
-		session->parameters = *parameters;
-		session->parameters.name = new_name;
-	} else {
-		const char *old_name = session->parameters.name;
-
-		session->parameters = *parameters;
-		session->parameters.name = old_name;
-	}
-
-	uds_log_notice("%s: %s", get_open_type_string(open_type), parameters->name);
+	format_dev_t(name, parameters->bdev->bd_dev);
+	uds_log_notice("%s: %s", get_open_type_string(open_type), name);
 	result = initialize_index_session(session, open_type);
 	if (result != UDS_SUCCESS)
 		uds_log_error_strerror(result, "Failed %s", get_open_type_string(open_type));
@@ -497,31 +481,23 @@ int uds_suspend_index_session(struct uds_index_session *session, bool save)
 	return uds_map_to_system_error(result);
 }
 
-static int replace_device(struct uds_index_session *session, const char *name)
+static int replace_device(struct uds_index_session *session, struct block_device *bdev)
 {
 	int result;
-	char *new_name;
 
-	result = uds_duplicate_string(name, "device name", &new_name);
+	result = uds_replace_index_storage(session->index, bdev);
 	if (result != UDS_SUCCESS)
 		return result;
 
-	result = uds_replace_index_storage(session->index, name);
-	if (result != UDS_SUCCESS) {
-		UDS_FREE(new_name);
-		return result;
-	}
-
-	uds_free_const(session->parameters.name);
-	session->parameters.name = new_name;
+	session->parameters.bdev = bdev;
 	return UDS_SUCCESS;
 }
 
 /*
- * Resume index operation after being suspended. If the index is suspended and the supplied name is
- * different from the current backing store, the index will start using the new backing store.
+ * Resume index operation after being suspended. If the index is suspended and the supplied bdev
+ * is different from the current backing store, the index will start using the new backing store.
  */
-int uds_resume_index_session(struct uds_index_session *session, const char *name)
+int uds_resume_index_session(struct uds_index_session *session, struct block_device *bdev)
 {
 	int result = UDS_SUCCESS;
 	bool no_work = false;
@@ -546,9 +522,10 @@ int uds_resume_index_session(struct uds_index_session *session, const char *name
 	if (no_work)
 		return result;
 
-	if ((name != NULL) && (session->index != NULL) &&
-	    (strcmp(name, session->parameters.name) != 0)) {
-		result = replace_device(session, name);
+	// FIXME: is bdev ever be NULL?
+	if (bdev != NULL && session->index != NULL &&
+	    bdev != session->parameters.bdev) {
+		result = replace_device(session, bdev);
 		if (result != UDS_SUCCESS) {
 			uds_lock_mutex(&session->request_mutex);
 			session->state &= ~IS_FLAG_WAITING;
@@ -709,7 +686,6 @@ int uds_destroy_index_session(struct uds_index_session *index_session)
 
 	wait_for_no_requests_in_progress(index_session);
 	result = save_and_free_index(index_session);
-	uds_free_const(index_session->parameters.name);
 	uds_request_queue_finish(index_session->callback_queue);
 	index_session->callback_queue = NULL;
 	uds_destroy_cond(&index_session->load_context.cond);
@@ -730,41 +706,19 @@ int uds_flush_index_session(struct uds_index_session *index_session)
 }
 
 /*
- * Return the most recent parameters used to open an index. The caller is responsible for freeing
- * the returned structure.
+ * Return the most recent parameters used to open an index. The caller is responsible
+ * for freeing the returned structure.
  */
 int uds_get_index_parameters(struct uds_index_session *index_session,
 			     struct uds_parameters **parameters)
 {
 	int result;
-	const char *name = index_session->parameters.name;
 
 	if (parameters == NULL) {
 		uds_log_error("received a NULL parameters pointer");
 		return -EINVAL;
 	}
 
-	if (name != NULL) {
-		char *name_copy = NULL;
-		size_t name_length = strlen(name) + 1;
-		struct uds_parameters *copy;
-
-		result = UDS_ALLOCATE_EXTENDED(struct uds_parameters,
-					       name_length,
-					       char,
-					       __func__,
-					       &copy);
-		if (result != UDS_SUCCESS)
-			return uds_map_to_system_error(result);
-
-		*copy = index_session->parameters;
-		name_copy = (char *) copy + sizeof(struct uds_parameters);
-		memcpy(name_copy, name, name_length);
-		copy->name = name_copy;
-		*parameters = copy;
-		return UDS_SUCCESS;
-	}
-
 	result = UDS_ALLOCATE(1, struct uds_parameters, __func__, parameters);
 	if (result == UDS_SUCCESS)
 		**parameters = index_session->parameters;
diff --git a/drivers/md/dm-vdo/index.c b/drivers/md/dm-vdo/index.c
index 0e78ff3e32199e..e8859cee2b93d6 100644
--- a/drivers/md/dm-vdo/index.c
+++ b/drivers/md/dm-vdo/index.c
@@ -1351,9 +1351,9 @@ int uds_save_index(struct uds_index *index)
 	return result;
 }
 
-int uds_replace_index_storage(struct uds_index *index, const char *path)
+int uds_replace_index_storage(struct uds_index *index, struct block_device *bdev)
 {
-	return uds_replace_volume_storage(index->volume, index->layout, path);
+	return uds_replace_volume_storage(index->volume, index->layout, bdev);
 }
 
 /* Accessing statistics should be safe from any thread. */
diff --git a/drivers/md/dm-vdo/index.h b/drivers/md/dm-vdo/index.h
index 1effe70d485495..aca61cabc433d0 100644
--- a/drivers/md/dm-vdo/index.h
+++ b/drivers/md/dm-vdo/index.h
@@ -72,7 +72,8 @@ int __must_check uds_save_index(struct uds_index *index);
 
 void uds_free_index(struct uds_index *index);
 
-int __must_check uds_replace_index_storage(struct uds_index *index, const char *path);
+int __must_check uds_replace_index_storage(struct uds_index *index,
+					   struct block_device *bdev);
 
 void uds_get_index_stats(struct uds_index *index, struct uds_index_stats *counters);
 
diff --git a/drivers/md/dm-vdo/io-factory.c b/drivers/md/dm-vdo/io-factory.c
index 4a550c90af9ab5..3bf20231a8720c 100644
--- a/drivers/md/dm-vdo/io-factory.c
+++ b/drivers/md/dm-vdo/io-factory.c
@@ -61,51 +61,14 @@ static void uds_get_io_factory(struct io_factory *factory)
 	atomic_inc(&factory->ref_count);
 }
 
-static int get_block_device_from_name(const char *name, struct block_device **bdev)
-{
-	dev_t device;
-	unsigned int major, minor;
-	char dummy;
-	const struct blk_holder_ops hops = { NULL };
-
-	/* Extract the major/minor numbers */
-	if (sscanf(name, "%u:%u%c", &major, &minor, &dummy) == 2) {
-		device = MKDEV(major, minor);
-		if (MAJOR(device) != major || MINOR(device) != minor) {
-			*bdev = NULL;
-			return uds_log_error_strerror(UDS_INVALID_ARGUMENT,
-						      "%s is not a valid block device",
-						      name);
-		}
-		*bdev = blkdev_get_by_dev(device, BLK_FMODE, NULL, &hops);
-	} else {
-		*bdev = blkdev_get_by_path(name, BLK_FMODE, NULL, &hops);
-	}
-
-	if (IS_ERR(*bdev)) {
-		uds_log_error_strerror(-PTR_ERR(*bdev), "%s is not a block device", name);
-		*bdev = NULL;
-		return UDS_INVALID_ARGUMENT;
-	}
-
-	return UDS_SUCCESS;
-}
-
-int uds_make_io_factory(const char *path, struct io_factory **factory_ptr)
+int uds_make_io_factory(struct block_device *bdev, struct io_factory **factory_ptr)
 {
 	int result;
-	struct block_device *bdev;
 	struct io_factory *factory;
 
-	result = get_block_device_from_name(path, &bdev);
-	if (result != UDS_SUCCESS)
-		return result;
-
 	result = UDS_ALLOCATE(1, struct io_factory, __func__, &factory);
-	if (result != UDS_SUCCESS) {
-		blkdev_put(bdev, NULL);
+	if (result != UDS_SUCCESS)
 		return result;
-	}
 
 	factory->bdev = bdev;
 	atomic_set_release(&factory->ref_count, 1);
@@ -114,16 +77,8 @@ int uds_make_io_factory(const char *path, struct io_factory **factory_ptr)
 	return UDS_SUCCESS;
 }
 
-int uds_replace_storage(struct io_factory *factory, const char *path)
+int uds_replace_storage(struct io_factory *factory, struct block_device *bdev)
 {
-	int result;
-	struct block_device *bdev;
-
-	result = get_block_device_from_name(path, &bdev);
-	if (result != UDS_SUCCESS)
-		return result;
-
-	blkdev_put(factory->bdev, NULL);
 	factory->bdev = bdev;
 	return UDS_SUCCESS;
 }
@@ -131,10 +86,8 @@ int uds_replace_storage(struct io_factory *factory, const char *path)
 /* Free an I/O factory once all references have been released. */
 void uds_put_io_factory(struct io_factory *factory)
 {
-	if (atomic_add_return(-1, &factory->ref_count) <= 0) {
-		blkdev_put(factory->bdev, NULL);
+	if (atomic_add_return(-1, &factory->ref_count) <= 0)
 		UDS_FREE(factory);
-	}
 }
 
 size_t uds_get_writable_size(struct io_factory *factory)
diff --git a/drivers/md/dm-vdo/io-factory.h b/drivers/md/dm-vdo/io-factory.h
index 41d8c7e9b10a48..ad648297815959 100644
--- a/drivers/md/dm-vdo/io-factory.h
+++ b/drivers/md/dm-vdo/io-factory.h
@@ -24,9 +24,9 @@ enum {
 	SECTORS_PER_BLOCK = UDS_BLOCK_SIZE >> SECTOR_SHIFT,
 };
 
-int __must_check uds_make_io_factory(const char *path, struct io_factory **factory_ptr);
+int __must_check uds_make_io_factory(struct block_device *bdev, struct io_factory **factory_ptr);
 
-int __must_check uds_replace_storage(struct io_factory *factory, const char *path);
+int __must_check uds_replace_storage(struct io_factory *factory, struct block_device *bdev);
 
 void uds_put_io_factory(struct io_factory *factory);
 
diff --git a/drivers/md/dm-vdo/uds.h b/drivers/md/dm-vdo/uds.h
index 71580c4098ce2b..cc791d45077bb2 100644
--- a/drivers/md/dm-vdo/uds.h
+++ b/drivers/md/dm-vdo/uds.h
@@ -125,8 +125,8 @@ struct uds_volume_record {
 };
 
 struct uds_parameters {
-	/* A string describing the storage device (a name or path) */
-	const char *name;
+	/* index block_device */
+	struct block_device *bdev;
 	/* The maximum allowable size of the index on storage */
 	size_t size;
 	/* The offset where the index should start */
@@ -306,10 +306,10 @@ int __must_check uds_suspend_index_session(struct uds_index_session *session, bo
 
 /*
  * Allow new index operations for an index, whether it was suspended or not. If the index is
- * suspended and the supplied name differs from the current backing store, the index will start
+ * suspended and the supplied bdev differs from the current backing store, the index will start
  * using the new backing store instead.
  */
-int __must_check uds_resume_index_session(struct uds_index_session *session, const char *name);
+int __must_check uds_resume_index_session(struct uds_index_session *session, struct block_device *bdev);
 
 /* Wait until all outstanding index operations are complete. */
 int __must_check uds_flush_index_session(struct uds_index_session *session);
diff --git a/drivers/md/dm-vdo/volume.c b/drivers/md/dm-vdo/volume.c
index 00dc217392b8c2..d32260e350ed54 100644
--- a/drivers/md/dm-vdo/volume.c
+++ b/drivers/md/dm-vdo/volume.c
@@ -1529,12 +1529,13 @@ int uds_find_volume_chapter_boundaries(struct volume *volume,
 }
 
 int __must_check
-uds_replace_volume_storage(struct volume *volume, struct index_layout *layout, const char *name)
+uds_replace_volume_storage(struct volume *volume, struct index_layout *layout,
+			   struct block_device *bdev)
 {
 	int result;
 	u32 i;
 
-	result = uds_replace_index_layout_storage(layout, name);
+	result = uds_replace_index_layout_storage(layout, bdev);
 	if (result != UDS_SUCCESS)
 		return result;
 
diff --git a/drivers/md/dm-vdo/volume.h b/drivers/md/dm-vdo/volume.h
index b01541814ed7f3..c8933f9505c4f4 100644
--- a/drivers/md/dm-vdo/volume.h
+++ b/drivers/md/dm-vdo/volume.h
@@ -128,7 +128,8 @@ int __must_check uds_make_volume(const struct configuration *config,
 void uds_free_volume(struct volume *volume);
 
 int __must_check
-uds_replace_volume_storage(struct volume *volume, struct index_layout *layout, const char *path);
+uds_replace_volume_storage(struct volume *volume, struct index_layout *layout,
+			   struct block_device *bdev);
 
 int __must_check uds_find_volume_chapter_boundaries(struct volume *volume,
 						    u64 *lowest_vcn,