Commit db8bd995 authored by Shuhei Matsumoto's avatar Shuhei Matsumoto Committed by Tomasz Zawadzki
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bdev/part: Add spdk_bdev_part_base_construct_ext() to pass bdev_name 



Add an new API spdk_bdev_part_base_construct_ext() to pass not bdev but
bdev_name to fix the race condition due to the time gap between
spdk_bdev_get_by_name() and spdk_bdev_open(). A pointer to a bdev is
valid only while the bdev is opened.

In the new API, spdk_bdev_get_by_name() is included in
spdk_bdev_part_base_construct_ext() and the caller has to know if
the bdev exists or not. Hence spdk_bdev_part_base_construct_ext()
returns return code and returns the created part object by the double
pointer.

Another critical change is that base is just freed if spdk_bdev_open_ext()
failed with -ENODEV. The reason is that if we call spdk_bdev_part_base_free()
for that case, the configuration is removed by the registered callback
and so bdev_examine() will not work.

The following patches will replace spdk_bdev_part_base_construct()
by spdk_bdev_part_base_construct_ext() for the corresponding bdev
modules.

Signed-off-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I2db027a159559c403cdfbd71800afba590b0f328
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4576


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: default avatarAleksey Marchuk <alexeymar@mellanox.com>
parent c59f0022

CHANGELOG.md

+8 −0
Original line number Diff line number Diff line
@@ -2,6 +2,14 @@ 


## v20.10: (Upcoming Release)



### bdev



A new `spdk_bdev_part_base_construct_ext` function has been added and the

`spdk_bdev_part_base_construct` has been deprecated.  The

`spdk_bdev_part_base_construct_ext` function takes bdev name as an argument instead

of bdev structure to avoid a race condition that can happen when the bdev is being

removed between a call to get its structure based on a name and actually openning it.



### dpdk



Updated DPDK submodule to DPDK 20.08.

include/spdk/bdev_module.h

+31 −1
Original line number Diff line number Diff line
@@ -1087,7 +1087,8 @@ void spdk_bdev_part_base_hotremove(struct spdk_bdev_part_base *part_base, 
				   struct bdev_part_tailq *tailq);



/**

 * Construct a new spdk_bdev_part_base on top of the provided bdev.

 * Construct a new spdk_bdev_part_base on top of the provided bdev

 * (deprecated. please use spdk_bdev_part_base_construct_ext).

 *

 * \param bdev The spdk_bdev upon which this base will be built.

 * \param remove_cb Function to be called upon hotremove of the bdev.
@@ -1114,6 +1115,35 @@ struct spdk_bdev_part_base *spdk_bdev_part_base_construct(struct spdk_bdev *bdev 
		spdk_io_channel_create_cb ch_create_cb,

		spdk_io_channel_destroy_cb ch_destroy_cb);



/**

 * Construct a new spdk_bdev_part_base on top of the provided bdev.

 *

 * \param bdev_name Name of the bdev upon which this base will be built.

 * \param remove_cb Function to be called upon hotremove of the bdev.

 * \param module The module to which this bdev base belongs.

 * \param fn_table Function table for communicating with the bdev backend.

 * \param tailq The head of the list of all spdk_bdev_part structures registered to this base's module.

 * \param free_fn User provided function to free base related context upon bdev removal or shutdown.

 * \param ctx Module specific context for this bdev part base.

 * \param channel_size Channel size in bytes.

 * \param ch_create_cb Called after a new channel is allocated.

 * \param ch_destroy_cb Called upon channel deletion.

 * \param base output parameter for the part object when operation is succssful.

 *

 * \return 0 if operation is successful, or suitable errno value otherwise.

 */

int spdk_bdev_part_base_construct_ext(const char *bdev_name,

				      spdk_bdev_remove_cb_t remove_cb,

				      struct spdk_bdev_module *module,

				      struct spdk_bdev_fn_table *fn_table,

				      struct bdev_part_tailq *tailq,

				      spdk_bdev_part_base_free_fn free_fn,

				      void *ctx,

				      uint32_t channel_size,

				      spdk_io_channel_create_cb ch_create_cb,

				      spdk_io_channel_destroy_cb ch_destroy_cb,

				      struct spdk_bdev_part_base **base);



/**

 * Create a logical spdk_bdev_part on top of a base.

 *

lib/bdev/part.c

+47 −16
Original line number Diff line number Diff line
@@ -433,26 +433,30 @@ bdev_part_base_event_cb(enum spdk_bdev_event_type type, struct spdk_bdev *bdev, 
	}

}



struct spdk_bdev_part_base *

	spdk_bdev_part_base_construct(struct spdk_bdev *bdev,

int

spdk_bdev_part_base_construct_ext(const char *bdev_name,

				  spdk_bdev_remove_cb_t remove_cb, struct spdk_bdev_module *module,

				  struct spdk_bdev_fn_table *fn_table, struct bdev_part_tailq *tailq,

				  spdk_bdev_part_base_free_fn free_fn, void *ctx,

				  uint32_t channel_size, spdk_io_channel_create_cb ch_create_cb,

			      spdk_io_channel_destroy_cb ch_destroy_cb)

				  spdk_io_channel_destroy_cb ch_destroy_cb,

				  struct spdk_bdev_part_base **_base)

{

	int rc;

	struct spdk_bdev_part_base *base;



	if (_base == NULL) {

		return -EINVAL;

	}



	base = calloc(1, sizeof(*base));

	if (!base) {

		SPDK_ERRLOG("Memory allocation failure\n");

		return NULL;

		return -ENOMEM;

	}

	fn_table->get_io_channel = bdev_part_get_io_channel;

	fn_table->io_type_supported = bdev_part_io_type_supported;



	base->bdev = bdev;

	base->desc = NULL;

	base->ref = 0;

	base->module = module;
@@ -466,19 +470,46 @@ struct spdk_bdev_part_base * 
	base->ch_destroy_cb = ch_destroy_cb;

	base->remove_cb = remove_cb;



	rc = spdk_bdev_open_ext(spdk_bdev_get_name(bdev), false, bdev_part_base_event_cb,

				base, &base->desc);

	rc = spdk_bdev_open_ext(bdev_name, false, bdev_part_base_event_cb, base, &base->desc);

	if (rc) {

		if (rc == -ENODEV) {

			free(base);

		} else {

			SPDK_ERRLOG("could not open bdev %s: %s\n", bdev_name, spdk_strerror(-rc));

			spdk_bdev_part_base_free(base);

		SPDK_ERRLOG("could not open bdev %s: %s\n", spdk_bdev_get_name(bdev),

			    spdk_strerror(-rc));

		return NULL;

		}

		return rc;

	}



	base->bdev = spdk_bdev_desc_get_bdev(base->desc);



	/* Save the thread where the base device is opened */

	base->thread = spdk_get_thread();



	*_base = base;



	return 0;

}



struct spdk_bdev_part_base *

	spdk_bdev_part_base_construct(struct spdk_bdev *bdev,

			      spdk_bdev_remove_cb_t remove_cb, struct spdk_bdev_module *module,

			      struct spdk_bdev_fn_table *fn_table, struct bdev_part_tailq *tailq,

			      spdk_bdev_part_base_free_fn free_fn, void *ctx,

			      uint32_t channel_size, spdk_io_channel_create_cb ch_create_cb,

			      spdk_io_channel_destroy_cb ch_destroy_cb)

{

	struct spdk_bdev_part_base *base = NULL;

	int rc;



	rc = spdk_bdev_part_base_construct_ext(spdk_bdev_get_name(bdev), remove_cb, module,

					       fn_table, tailq, free_fn, ctx,

					       channel_size, ch_create_cb, ch_destroy_cb, &base);

	if (rc == 0) {

		return base;

	} else {

		return NULL;

	}

}



int

lib/bdev/spdk_bdev.map

+1 −0
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ 
	spdk_bdev_part_free;

	spdk_bdev_part_base_hotremove;

	spdk_bdev_part_base_construct;

	spdk_bdev_part_base_construct_ext;

	spdk_bdev_part_construct;

	spdk_bdev_part_submit_request;

	spdk_bdev_part_get_bdev;