bdev: rework bdev module registration (4d367354) · Commits · Public Repositories / spdk

doc/bdev_module.md

+11 −7

Original line number	Diff line number	Diff line
		@@ -25,13 +25,17 @@ module, add a new directory with a single C file and a Makefile. A great
		starting point is to copy the existing 'null' bdev module.

		The primary interface that bdev modules will interact with is in
		include/spdk_internal/bdev.h. In that header a macro is defined that declares
		a new bdev module named SPDK_BDEV_MODULE_REGISTER. This macro takes as
		arguments a number of function pointers that are used to initialize, tear
		down, and get the configuration of the module. There are also arguments to
		specify context size, which is scratch space that will be allocated in each
		I/O request for use by this module, and a callback that will be called each
		time a new bdev is registered by another module.
		include/spdk_internal/bdev.h. In that header a macro is defined that registers
		a new bdev module - SPDK_BDEV_MODULE_REGISTER. This macro take as argument a
		pointer spdk_bdev_module_if structure that is used to register new bdev module.

		The spdk_bdev_module_if structure describes the module properties like
		initialization (`module_init`) and teardown (`module_fini`) functions,
		the function that returns context size (`get_ctx_size`) - scratch space that
		will be allocated in each I/O request for use by this module, and a callback
		that will be called each time a new bdev is registered by another module
		(`examine`). Please check the documentation of struct spdk_bdev_module_if for
		more details.

		## Creating Bdevs

include/spdk_internal/bdev.h

+29 −31

Original line number	Diff line number	Diff line
		@@ -119,11 +119,22 @@ struct spdk_bdev_module_if {
		/**
		* Count of bdev inits/examinations in progress. Used by generic bdev
		* layer and must not be modified by bdev modules.
		*
		* \note Used internally by bdev subsystem, don't change this value in bdev module.
		*/
		uint32_t action_in_progress;

		/**
		* Denotes if the module_init function may complete asynchronously. If set to true,
		* the module initialization has to be explicitly completed by calling
		* spdk_bdev_module_init_done().
		*/
		bool async_init;

		/**
		* Denotes if the module_fini function may complete asynchronously.
		* If set to true finishing has to be explicitly completed by calling
		* spdk_bdev_module_fini_done().
		*/
		bool async_fini;

		@@ -515,6 +526,14 @@ void spdk_scsi_nvme_translate(const struct spdk_bdev_io *bdev_io,

		void spdk_bdev_module_list_add(struct spdk_bdev_module_if *bdev_module);

		/**
		* Find registered module with name pointed by \c name.
		*
		* \param name name of module to be searched for.
		* \return pointer to module or NULL if no module with \c name exist
		*/
		struct spdk_bdev_module_if spdk_bdev_module_list_find(const char name);

		static inline struct spdk_bdev_io *
		spdk_bdev_io_from_ctx(void *ctx)
		{
		@@ -571,47 +590,26 @@ int spdk_bdev_part_construct(struct spdk_bdev_part *part, struct spdk_bdev_part_
		char *product_name);
		void spdk_bdev_part_submit_request(struct spdk_bdev_part_channel ch, struct spdk_bdev_io bdev_io);

		#define SPDK_BDEV_MODULE_REGISTER(_name, init_fn, fini_fn, config_fn, ctx_size_fn, examine_fn) \
		static struct spdk_bdev_module_if _name ## _if = { \
		.name = #_name, \
		.module_init = init_fn, \
		.module_fini = fini_fn, \
		.config_text = config_fn, \
		.get_ctx_size = ctx_size_fn, \
		.examine = examine_fn, \
		}; \
		__attribute__((constructor)) static void _name ## _init(void) \
		{ \
		spdk_bdev_module_list_add(&_name ## _if); \
		}

		#define SPDK_GET_BDEV_MODULE(name) (&name ## _if)

		/*
		* Set module initialization to be asynchronous. After using this macro, the module
		* initialization has to be explicitly completed by calling spdk_bdev_module_init_done().
		* Macro used to register module for later initialization.
		*/
		#define SPDK_BDEV_MODULE_ASYNC_INIT(name) \
		__attribute__((constructor)) static void name ## _async_init(void) \
		#define SPDK_BDEV_MODULE_REGISTER(_module) \
		__attribute__((constructor)) static void \
		SPDK_BDEV_MODULE_REGISTER_FN_NAME(__LINE__) (void) \
		{ \
		SPDK_GET_BDEV_MODULE(name)->action_in_progress = 1; \
		spdk_bdev_module_list_add(_module); \
		}

		/*
		* Set module finish to be asynchronous. After using this macro, the module
		* finishing has to be explicitly completed by calling spdk_bdev_module_fini_done().
		* This is helper macro for automatic function generation.
		*
		*/
		#define SPDK_BDEV_MODULE_ASYNC_FINI(name) \
		__attribute__((constructor)) static void name ## _async_fini(void) \
		{ \
		SPDK_GET_BDEV_MODULE(name)->async_fini = true; \
		}
		#define SPDK_BDEV_MODULE_REGISTER_FN_NAME(line) SPDK_BDEV_MODULE_REGISTER_FN_NAME_(line)

		/*
		* Modules are not required to use this macro. It allows modules to reference the module with
		* SPDK_GET_BDEV_MODULE() before it is defined by SPDK_BDEV_MODULE_REGISTER.
		* Second helper macro for "stringize" trick to work.
		*/
		#define SPDK_DECLARE_BDEV_MODULE(name) \
		static struct spdk_bdev_module_if name ## _if;
		#define SPDK_BDEV_MODULE_REGISTER_FN_NAME_(line) spdk_bdev_module_if_register_ ## line

		#endif /* SPDK_INTERNAL_BDEV_H */

lib/bdev/aio/bdev_aio.c

+11 −3

Original line number	Diff line number	Diff line
		@@ -59,8 +59,16 @@ bdev_aio_get_ctx_size(void)
		return sizeof(struct bdev_aio_task);
		}

		SPDK_BDEV_MODULE_REGISTER(aio, bdev_aio_initialize, NULL, bdev_aio_get_spdk_running_config,
		bdev_aio_get_ctx_size, NULL)
		static struct spdk_bdev_module_if aio_if = {
		.name = "aio",
		.module_init = bdev_aio_initialize,
		.module_fini = NULL,
		.config_text = bdev_aio_get_spdk_running_config,
		.get_ctx_size = bdev_aio_get_ctx_size,
		.examine = NULL,
		};

		SPDK_BDEV_MODULE_REGISTER(&aio_if)

		static int
		bdev_aio_open(struct file_disk *disk)
		@@ -450,7 +458,7 @@ create_aio_disk(const char name, const char filename, uint32_t block_size)
		goto error_return;
		}
		fdisk->disk.product_name = "AIO disk";
		fdisk->disk.module = SPDK_GET_BDEV_MODULE(aio);
		fdisk->disk.module = &aio_if;

		fdisk->disk.need_aligned_buffer = 1;
		fdisk->disk.write_cache = 1;

lib/bdev/bdev.c

+24 −0

Original line number	Diff line number	Diff line
		@@ -2391,6 +2391,16 @@ spdk_bdev_io_get_iovec(struct spdk_bdev_io bdev_io, struct iovec iovp, int i
		void
		spdk_bdev_module_list_add(struct spdk_bdev_module_if *bdev_module)
		{

		if (spdk_bdev_module_list_find(bdev_module->name)) {
		fprintf(stderr, "ERROR: module '%s' already registered.\n", bdev_module->name);
		assert(false);
		}

		if (bdev_module->async_init) {
		bdev_module->action_in_progress = 1;
		}

		/*
		* Modules with examine callbacks must be initialized first, so they are
		* ready to handle examine callbacks from later modules that will
		@@ -2403,6 +2413,20 @@ spdk_bdev_module_list_add(struct spdk_bdev_module_if *bdev_module)
		}
		}

		struct spdk_bdev_module_if *
		spdk_bdev_module_list_find(const char *name)
		{
		struct spdk_bdev_module_if *bdev_module;

		TAILQ_FOREACH(bdev_module, &g_bdev_mgr.bdev_modules, tailq) {
		if (strcmp(name, bdev_module->name) == 0) {
		break;
		}
		}

		return bdev_module;
		}

		static void
		spdk_bdev_write_zeroes_split(struct spdk_bdev_io bdev_io, bool success, void cb_arg)
		{

lib/bdev/error/vbdev_error.c

+17 −8

Original line number	Diff line number	Diff line
		@@ -48,8 +48,6 @@

		#include "vbdev_error.h"

		SPDK_DECLARE_BDEV_MODULE(error);

		struct vbdev_error_info {
		bool enabled;
		uint32_t error_type;
		@@ -70,6 +68,20 @@ struct error_channel {
		static pthread_mutex_t g_vbdev_error_mutex = PTHREAD_MUTEX_INITIALIZER;
		static SPDK_BDEV_PART_TAILQ g_error_disks = TAILQ_HEAD_INITIALIZER(g_error_disks);

		static int vbdev_error_init(void);

		static void vbdev_error_examine(struct spdk_bdev *bdev);

		static struct spdk_bdev_module_if error_if = {
		.name = "error",
		.module_init = vbdev_error_init,
		.module_fini = NULL,
		.examine = vbdev_error_examine,

		};

		SPDK_BDEV_MODULE_REGISTER(&error_if)

		static void
		spdk_error_free_base(struct spdk_bdev_part_base *base)
		{
		@@ -235,7 +247,7 @@ spdk_vbdev_error_create(struct spdk_bdev *base_bdev)

		rc = spdk_bdev_part_base_construct(base, base_bdev,
		spdk_vbdev_error_base_bdev_hotremove_cb,
		SPDK_GET_BDEV_MODULE(error), &vbdev_error_fn_table,
		&error_if, &vbdev_error_fn_table,
		&g_error_disks, spdk_error_free_base,
		sizeof(struct error_channel), NULL, NULL);
		if (rc) {
		@@ -288,7 +300,7 @@ vbdev_error_examine(struct spdk_bdev *bdev)

		sp = spdk_conf_find_section(NULL, "BdevError");
		if (sp == NULL) {
		spdk_bdev_module_examine_done(SPDK_GET_BDEV_MODULE(error));
		spdk_bdev_module_examine_done(&error_if);
		return;
		}

		@@ -313,8 +325,5 @@ vbdev_error_examine(struct spdk_bdev *bdev)
		}
		}

		spdk_bdev_module_examine_done(SPDK_GET_BDEV_MODULE(error));
		spdk_bdev_module_examine_done(&error_if);
		}

		SPDK_BDEV_MODULE_REGISTER(error, vbdev_error_init, NULL, NULL, NULL,
		vbdev_error_examine)