From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Wed, 8 Oct 2014 06:19:20 +0000 (+0000)
Subject: vhost-scsi: Take configfs group dependency during VHOST_SCSI_SET_ENDPOINT
X-Git-Tag: omap-for-v3.19/fixes-for-merge-window~89^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab8edab132829b26dd13db6caca3c242cce35dc1;p=pandora-kernel.git

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>
---

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