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| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2014-10-08 06:19:20 +0000 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2014-10-28 13:54:16 -0700 |
| commit | ab8edab132829b26dd13db6caca3c242cce35dc1 (patch) | |
| tree | aab2f98b7773095dcdfb799d52af64430d1a2f35 /drivers/vhost | |
| parent | 885e7b0e181c14e4d0ddd26c688bad2b84c1ada9 (diff) | |
| download | blackbird-obmc-linux-ab8edab132829b26dd13db6caca3c242cce35dc1.tar.gz blackbird-obmc-linux-ab8edab132829b26dd13db6caca3c242cce35dc1.zip | |
vhost-scsi: Take configfs group dependency during VHOST_SCSI_SET_ENDPOINT
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@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: <stable@vger.kernel.org> # 3.6+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/vhost')
| -rw-r--r-- | drivers/vhost/scsi.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 69906cacd04f..a17f11850669 100644 --- 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_scsi *vs, 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_scsi *vs, 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++) { |
