Commit e3c26a05 authored by lorneli's avatar lorneli Committed by Jim Harris
Browse files

bdev: reduce critical area in spdk_bdev_open 



Since bdev->internal.mutex protects variables in bdev->internal,
there's no need to init the fields of spdk_bdev_desc struct and
free the struct when claim_module exists within the mutex lock.

Reducing critical area could help to reduce lock competition
caused by opening bdev concurrently.

Change-Id: Ie6b2a63e44a97cfed914fa6d8adef2c5ec3ac300
Signed-off-by: default avatarlorneli <lorneli@163.com>
Reviewed-on: https://review.gerrithub.io/c/438514


Reviewed-by: default avatarwuzhouhui <wuzhouhui@kingsoft.com>
Reviewed-by: default avatarGangCao <gang.cao@intel.com>
Reviewed-by: default avatarDarek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent 0dff1888

lib/bdev/bdev.c

+9 −8
Original line number Diff line number Diff line
@@ -3624,25 +3624,26 @@ spdk_bdev_open(struct spdk_bdev *bdev, bool write, spdk_bdev_remove_cb_t remove_ 
	SPDK_DEBUGLOG(SPDK_LOG_BDEV, "Opening descriptor %p for bdev %s on thread %p\n", desc, bdev->name,

		      spdk_get_thread());



	desc->bdev = bdev;

	desc->thread = thread;

	desc->remove_cb = remove_cb;

	desc->remove_ctx = remove_ctx;

	desc->write = write;

	*_desc = desc;



	pthread_mutex_lock(&bdev->internal.mutex);



	if (write && bdev->internal.claim_module) {

		SPDK_ERRLOG("Could not open %s - %s module already claimed it\n",

			    bdev->name, bdev->internal.claim_module->name);

		free(desc);

		pthread_mutex_unlock(&bdev->internal.mutex);

		free(desc);

		*_desc = NULL;

		return -EPERM;

	}



	TAILQ_INSERT_TAIL(&bdev->internal.open_descs, desc, link);



	desc->bdev = bdev;

	desc->thread = thread;

	desc->remove_cb = remove_cb;

	desc->remove_ctx = remove_ctx;

	desc->write = write;

	*_desc = desc;



	pthread_mutex_unlock(&bdev->internal.mutex);



	return 0;