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tcm_vhost: Refactor the lock nesting rule

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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: Asias He <asias@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Asias He 2013-04-25 15:35:20 +08:00 committed by Nicholas Bellinger
parent d3682b1aeb
commit f2b7daf5b1
1 changed files with 19 additions and 13 deletions
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32
drivers/vhost/tcm_vhost.c
View file

@ -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;
}