This is a note to let you know that I've just added the patch titled
vhost-scsi: Take configfs group dependency during VHOST_SCSI_SET_ENDPOINT
to the 3.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vhost-scsi-take-configfs-group-dependency-during-vhost_scsi_set_endpoint.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ab8edab132829b26dd13db6caca3c242cce35dc1 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Date: Wed, 8 Oct 2014 06:19:20 +0000
Subject: vhost-scsi: Take configfs group dependency during VHOST_SCSI_SET_ENDPOINT
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
commit ab8edab132829b26dd13db6caca3c242cce35dc1 upstream.
This patch addresses a bug where individual vhost-scsi configfs endpoint
groups can be removed from below while active exports to QEMU userspace
still exist, resulting in an OOPs.
It adds a configfs_depend_item() in vhost_scsi_set_endpoint() to obtain
an explicit dependency on se_tpg->tpg_group in order to prevent individual
vhost-scsi WWPN endpoints from being released via normal configfs methods
while an QEMU ioctl reference still exists.
Also, add matching configfs_undepend_item() in vhost_scsi_clear_endpoint()
to release the dependency, once QEMU's reference to the individual group
at /sys/kernel/config/target/vhost/$WWPN/$TPGT is released.
(Fix up vhost_scsi_clear_endpoint() error path - DanC)
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/vhost/scsi.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1312,6 +1312,7 @@ static int
vhost_scsi_set_endpoint(struct vhost_scsi *vs,
struct vhost_scsi_target *t)
{
+ struct se_portal_group *se_tpg;
struct tcm_vhost_tport *tv_tport;
struct tcm_vhost_tpg *tpg;
struct tcm_vhost_tpg **vs_tpg;
@@ -1359,6 +1360,21 @@ vhost_scsi_set_endpoint(struct vhost_scs
ret = -EEXIST;
goto out;
}
+ /*
+ * In order to ensure individual vhost-scsi configfs
+ * groups cannot be removed while in use by vhost ioctl,
+ * go ahead and take an explicit se_tpg->tpg_group.cg_item
+ * dependency now.
+ */
+ se_tpg = &tpg->se_tpg;
+ ret = configfs_depend_item(se_tpg->se_tpg_tfo->tf_subsys,
+ &se_tpg->tpg_group.cg_item);
+ if (ret) {
+ pr_warn("configfs_depend_item() failed: %d\n", ret);
+ kfree(vs_tpg);
+ mutex_unlock(&tpg->tv_tpg_mutex);
+ goto out;
+ }
tpg->tv_tpg_vhost_count++;
tpg->vhost_scsi = vs;
vs_tpg[tpg->tport_tpgt] = tpg;
@@ -1401,6 +1417,7 @@ static int
vhost_scsi_clear_endpoint(struct vhost_scsi *vs,
struct vhost_scsi_target *t)
{
+ struct se_portal_group *se_tpg;
struct tcm_vhost_tport *tv_tport;
struct tcm_vhost_tpg *tpg;
struct vhost_virtqueue *vq;
@@ -1449,6 +1466,13 @@ vhost_scsi_clear_endpoint(struct vhost_s
vs->vs_tpg[target] = NULL;
match = true;
mutex_unlock(&tpg->tv_tpg_mutex);
+ /*
+ * Release se_tpg->tpg_group.cg_item configfs dependency now
+ * to allow vhost-scsi WWPN se_tpg->tpg_group shutdown to occur.
+ */
+ se_tpg = &tpg->se_tpg;
+ configfs_undepend_item(se_tpg->se_tpg_tfo->tf_subsys,
+ &se_tpg->tpg_group.cg_item);
}
if (match) {
for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {
Patches currently in stable-queue which might be from nab@xxxxxxxxxxxxxxx are
queue-3.17/ib_isert-add-max_send_sge-2-minimum-for-control-pdu-responses.patch
queue-3.17/target-don-t-call-tfo-write_pending-if-data_length-0.patch
queue-3.17/iser-target-handle-device_removal-event-on-network-portal-listener-correctly.patch
queue-3.17/vhost-scsi-take-configfs-group-dependency-during-vhost_scsi_set_endpoint.patch
queue-3.17/ib-isert-adjust-cq-size-to-hw-limits.patch
queue-3.17/srp-target-retry-when-qp-creation-fails-with-enomem.patch
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