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Commit f2b7daf5 authored by Asias He's avatar Asias He Committed by Nicholas Bellinger
Browse files

tcm_vhost: Refactor the lock nesting rule 



We want to use tcm_vhost_mutex to make sure hotplug/hotunplug will not
happen when set_endpoint/clear_endpoint is in process.

Signed-off-by: default avatarAsias He <asias@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent d3682b1a

drivers/vhost/tcm_vhost.c

+19 −13
Original line number Diff line number Diff line
@@ -808,6 +808,9 @@ static void vhost_scsi_flush(struct vhost_scsi *vs) 
/*

 * Called from vhost_scsi_ioctl() context to walk the list of available

 * tcm_vhost_tpg with an active struct tcm_vhost_nexus

 *

 *  The lock nesting rule is:

 *    tcm_vhost_mutex -> vs->dev.mutex -> tpg->tv_tpg_mutex -> vq->mutex

 */

static int vhost_scsi_set_endpoint(

	struct vhost_scsi *vs,
@@ -820,26 +823,27 @@ static int vhost_scsi_set_endpoint( 
	int index, ret, i, len;

	bool match = false;



	mutex_lock(&tcm_vhost_mutex);

	mutex_lock(&vs->dev.mutex);



	/* Verify that ring has been setup correctly. */

	for (index = 0; index < vs->dev.nvqs; ++index) {

		/* Verify that ring has been setup correctly. */

		if (!vhost_vq_access_ok(&vs->vqs[index])) {

			mutex_unlock(&vs->dev.mutex);

			return -EFAULT;

			ret = -EFAULT;

			goto out;

		}

	}



	len = sizeof(vs_tpg[0]) * VHOST_SCSI_MAX_TARGET;

	vs_tpg = kzalloc(len, GFP_KERNEL);

	if (!vs_tpg) {

		mutex_unlock(&vs->dev.mutex);

		return -ENOMEM;

		ret = -ENOMEM;

		goto out;

	}

	if (vs->vs_tpg)

		memcpy(vs_tpg, vs->vs_tpg, len);



	mutex_lock(&tcm_vhost_mutex);

	list_for_each_entry(tv_tpg, &tcm_vhost_list, tv_tpg_list) {

		mutex_lock(&tv_tpg->tv_tpg_mutex);

		if (!tv_tpg->tpg_nexus) {
@@ -854,11 +858,10 @@ static int vhost_scsi_set_endpoint( 


		if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {

			if (vs->vs_tpg && vs->vs_tpg[tv_tpg->tport_tpgt]) {

				mutex_unlock(&tv_tpg->tv_tpg_mutex);

				mutex_unlock(&tcm_vhost_mutex);

				mutex_unlock(&vs->dev.mutex);

				kfree(vs_tpg);

				return -EEXIST;

				mutex_unlock(&tv_tpg->tv_tpg_mutex);

				ret = -EEXIST;

				goto out;

			}

			tv_tpg->tv_tpg_vhost_count++;

			vs_tpg[tv_tpg->tport_tpgt] = tv_tpg;
@@ -867,7 +870,6 @@ static int vhost_scsi_set_endpoint( 
		}

		mutex_unlock(&tv_tpg->tv_tpg_mutex);

	}

	mutex_unlock(&tcm_vhost_mutex);



	if (match) {

		memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
@@ -893,7 +895,9 @@ static int vhost_scsi_set_endpoint( 
	kfree(vs->vs_tpg);

	vs->vs_tpg = vs_tpg;



out:

	mutex_unlock(&vs->dev.mutex);

	mutex_unlock(&tcm_vhost_mutex);

	return ret;

}
@@ -908,6 +912,7 @@ static int vhost_scsi_clear_endpoint( 
	int index, ret, i;

	u8 target;



	mutex_lock(&tcm_vhost_mutex);

	mutex_lock(&vs->dev.mutex);

	/* Verify that ring has been setup correctly. */

	for (index = 0; index < vs->dev.nvqs; ++index) {
@@ -918,8 +923,8 @@ static int vhost_scsi_clear_endpoint( 
	}



	if (!vs->vs_tpg) {

		mutex_unlock(&vs->dev.mutex);

		return 0;

		ret = 0;

		goto err_dev;

	}



	for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {
@@ -965,13 +970,14 @@ static int vhost_scsi_clear_endpoint( 
	kfree(vs->vs_tpg);

	vs->vs_tpg = NULL;

	mutex_unlock(&vs->dev.mutex);



	mutex_unlock(&tcm_vhost_mutex);

	return 0;



err_tpg:

	mutex_unlock(&tv_tpg->tv_tpg_mutex);

err_dev:

	mutex_unlock(&vs->dev.mutex);

	mutex_unlock(&tcm_vhost_mutex);

	return ret;

}