Commit 96c007d3 authored by Shuhei Matsumoto's avatar Shuhei Matsumoto Committed by Tomasz Zawadzki
Browse files

bdev: Add spdk_bdev_unregister_by_name() to handle race condtions 



To unregister a bdev more correctly, we had to call
spdk_bdev_open_ext(), spdk_bdev_desc_get_bdev(), spdk_bdev_unregister(),
and then spdk_bdev_close(). This was correct but complicated.

Hence add a new public API spdk_bdev_unregister_by_name() which does
the whole correct sequence of bdev unregistration.

Signed-off-by: default avatarShuhei Matsumoto <smatsumoto@nvidia.com>
Change-Id: I9068d4ac49dca944436e0ba587308fd356dfef75
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/12065


Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Reviewed-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent b0aba3fc

CHANGELOG.md

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ fragment copies. 


Removed deprecated spdk_bdev_module_finish_done(). Use spdk_bdev_module_fini_done() instead.



A new API `spdk_bdev_unregister_by_name` was added to handle race conditions correctly.



### idxd



A new parameter `flags` was added to all low level submission and preparation

include/spdk/bdev_module.h

+21 −2
Original line number Diff line number Diff line
@@ -803,16 +803,35 @@ int spdk_bdev_register(struct spdk_bdev *bdev); 


/**

 * Start unregistering a bdev. This will notify each currently open descriptor

 * on this bdev about the hotremoval in hopes that the upper layers will stop

 * using this bdev and manually close all the descriptors with spdk_bdev_close().

 * on this bdev of the hotremoval to request the upper layers to stop using this bdev

 * and manually close all the descriptors with spdk_bdev_close().

 * The actual bdev unregistration may be deferred until all descriptors are closed.

 *

 * Note: spdk_bdev_unregister() can be unsafe unless the bdev is not opened before and

 * closed after unregistration. It is recommended to use spdk_bdev_unregister_by_name().

 *

 * \param bdev Block device to unregister.

 * \param cb_fn Callback function to be called when the unregister is complete.

 * \param cb_arg Argument to be supplied to cb_fn

 */

void spdk_bdev_unregister(struct spdk_bdev *bdev, spdk_bdev_unregister_cb cb_fn, void *cb_arg);



/**

 * Start unregistering a bdev. This will notify each currently open descriptor

 * on this bdev of the hotremoval to request the upper layer to stop using this bdev

 * and manually close all the descriptors with spdk_bdev_close().

 * The actual bdev unregistration may be deferred until all descriptors are closed.

 *

 * \param bdev_name Block device name to unregister.

 * \param module Module by which the block device was registered.

 * \param cb_fn Callback function to be called when the unregister is complete.

 * \param cb_arg Argument to be supplied to cb_fn

 *

 * \return 0 on success, or suitable errno value otherwise

 */

int spdk_bdev_unregister_by_name(const char *bdev_name, struct spdk_bdev_module *module,

				 spdk_bdev_unregister_cb cb_fn, void *cb_arg);



/**

 * Invokes the unregister callback of a bdev backing a virtual bdev.

 *

lib/bdev/bdev.c

+36 −0
Original line number Diff line number Diff line
@@ -6145,6 +6145,42 @@ spdk_bdev_unregister(struct spdk_bdev *bdev, spdk_bdev_unregister_cb cb_fn, void 
	}

}



static void

_tmp_bdev_event_cb(enum spdk_bdev_event_type type, struct spdk_bdev *bdev, void *ctx)

{

	SPDK_NOTICELOG("Unexpected event type: %d\n", type);

}



int

spdk_bdev_unregister_by_name(const char *bdev_name, struct spdk_bdev_module *module,

			     spdk_bdev_unregister_cb cb_fn, void *cb_arg)

{

	struct spdk_bdev_desc *desc;

	struct spdk_bdev *bdev;

	int rc;



	rc = spdk_bdev_open_ext(bdev_name, false, _tmp_bdev_event_cb, NULL, &desc);

	if (rc != 0) {

		SPDK_ERRLOG("Failed to open bdev with name: %s\n", bdev_name);

		return rc;

	}



	bdev = spdk_bdev_desc_get_bdev(desc);



	if (bdev->module != module) {

		spdk_bdev_close(desc);

		SPDK_ERRLOG("Bdev %s was not registered by the specified module.\n",

			    bdev_name);

		return -ENODEV;

	}



	spdk_bdev_unregister(bdev, cb_fn, cb_arg);



	spdk_bdev_close(desc);



	return 0;

}



static int

bdev_start_qos(struct spdk_bdev *bdev)

{

lib/bdev/spdk_bdev.map

+1 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ 
	# Public functions in bdev_module.h

	spdk_bdev_register;

	spdk_bdev_unregister;

	spdk_bdev_unregister_by_name;

	spdk_bdev_destruct_done;

	spdk_bdev_module_examine_done;

	spdk_bdev_module_init_done;

test/unit/lib/bdev/bdev.c/bdev_ut.c

+37 −0
Original line number Diff line number Diff line
@@ -5153,6 +5153,42 @@ bdev_register_uuid_alias(void) 
	poll_threads();

}



static void

bdev_unregister_by_name(void)

{

	struct spdk_bdev *bdev;

	int rc;



	bdev = allocate_bdev("bdev");



	g_event_type1 = 0xFF;

	g_unregister_arg = NULL;

	g_unregister_rc = -1;



	rc = spdk_bdev_unregister_by_name("bdev1", &bdev_ut_if, bdev_unregister_cb, (void *)0x12345678);

	CU_ASSERT(rc == -ENODEV);



	rc = spdk_bdev_unregister_by_name("bdev", &vbdev_ut_if, bdev_unregister_cb, (void *)0x12345678);

	CU_ASSERT(rc == -ENODEV);



	rc = spdk_bdev_unregister_by_name("bdev", &bdev_ut_if, bdev_unregister_cb, (void *)0x12345678);

	CU_ASSERT(rc == 0);



	/* Check that unregister callback is delayed */

	CU_ASSERT(g_unregister_arg == NULL);

	CU_ASSERT(g_unregister_rc == -1);



	poll_threads();



	/* Event callback shall not be issued because device was closed */

	CU_ASSERT(g_event_type1 == 0xFF);

	/* Unregister callback is issued */

	CU_ASSERT(g_unregister_arg == (void *)0x12345678);

	CU_ASSERT(g_unregister_rc == 0);



	free_bdev(bdev);

}



int

main(int argc, char **argv)

{
@@ -5202,6 +5238,7 @@ main(int argc, char **argv) 
	CU_ADD_TEST(suite, bdev_get_memory_domains);

	CU_ADD_TEST(suite, bdev_writev_readv_ext);

	CU_ADD_TEST(suite, bdev_register_uuid_alias);

	CU_ADD_TEST(suite, bdev_unregister_by_name);



	allocate_cores(1);

	allocate_threads(1);