From: Mike Christie <michael.christie@oracle.com> To: target-devel@vger.kernel.org, linux-scsi@vger.kernel.org, stefanha@redhat.com, jasowang@redhat.com, mst@redhat.com, sgarzare@redhat.com, virtualization@lists.linux-foundation.org Subject: [PATCH v2 7/7] vhost-scsi: Reduce vhost_scsi_mutex use Date: Mon, 20 Mar 2023 21:06:24 -0500 [thread overview] Message-ID: <20230321020624.13323-8-michael.christie@oracle.com> (raw) In-Reply-To: <20230321020624.13323-1-michael.christie@oracle.com> We on longer need to hold the vhost_scsi_mutex the entire time we set/clear the endpoint. The tv_tpg_mutex handles tpg accesses not related to the tpg list, the port link/unlink functions use the tv_tpg_mutex while accessing the tpg->vhost_scsi pointer, vhost_scsi_do_plug will no longer queue events after the virtqueue's backend has been cleared and flushed, and we don't drop our refcount to the tpg until after we have stopped cmds and wait for outstanding cmds to complete. This moves the vhost_scsi_mutex use to it's documented use of being used to access the tpg list. We then don't need to hold it while a flush is being performed causing other device's vhost_scsi_set_endpoint and vhost_scsi_make_tpg/vhost_scsi_drop_tpg calls to have to wait on a flakey device. Signed-off-by: Mike Christie <michael.christie@oracle.com> --- drivers/vhost/scsi.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index d4372a4aff49..3b0b556c57ef 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -229,7 +229,10 @@ struct vhost_scsi_ctx { struct iov_iter out_iter; }; -/* Global spinlock to protect vhost_scsi TPG list for vhost IOCTL access */ +/* + * Global mutex to protect vhost_scsi TPG list for vhost IOCTLs and LIO + * configfs management operations. + */ static DEFINE_MUTEX(vhost_scsi_mutex); static LIST_HEAD(vhost_scsi_list); @@ -1526,7 +1529,7 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds) * vhost_scsi_tpg with an active struct vhost_scsi_nexus * * The lock nesting rule is: - * vhost_scsi_mutex -> vs->dev.mutex -> tpg->tv_tpg_mutex -> vq->mutex + * vs->dev.mutex -> vhost_scsi_mutex -> tpg->tv_tpg_mutex -> vq->mutex */ static int vhost_scsi_set_endpoint(struct vhost_scsi *vs, @@ -1540,7 +1543,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, int index, ret, i, len; bool match = false; - mutex_lock(&vhost_scsi_mutex); mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ @@ -1561,6 +1563,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (vs->vs_tpg) memcpy(vs_tpg, vs->vs_tpg, len); + mutex_lock(&vhost_scsi_mutex); list_for_each_entry(tpg, &vhost_scsi_list, tv_tpg_list) { mutex_lock(&tpg->tv_tpg_mutex); if (!tpg->tpg_nexus) { @@ -1576,6 +1579,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) { if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) { mutex_unlock(&tpg->tv_tpg_mutex); + mutex_unlock(&vhost_scsi_mutex); ret = -EEXIST; goto undepend; } @@ -1590,6 +1594,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (ret) { pr_warn("target_depend_item() failed: %d\n", ret); mutex_unlock(&tpg->tv_tpg_mutex); + mutex_unlock(&vhost_scsi_mutex); goto undepend; } tpg->tv_tpg_vhost_count++; @@ -1599,6 +1604,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, } mutex_unlock(&tpg->tv_tpg_mutex); } + mutex_unlock(&vhost_scsi_mutex); if (match) { memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn, @@ -1654,7 +1660,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, kfree(vs_tpg); out: mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return ret; } @@ -1670,7 +1675,6 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, int index, ret, i; u8 target; - mutex_lock(&vhost_scsi_mutex); mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ for (index = 0; index < vs->dev.nvqs; ++index) { @@ -1757,12 +1761,10 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, vs->vs_tpg = NULL; WARN_ON(vs->vs_events_nr); mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return 0; err_dev: mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return ret; } -- 2.25.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
WARNING: multiple messages have this Message-ID (diff)
From: Mike Christie <michael.christie@oracle.com> To: target-devel@vger.kernel.org, linux-scsi@vger.kernel.org, stefanha@redhat.com, jasowang@redhat.com, mst@redhat.com, sgarzare@redhat.com, virtualization@lists.linux-foundation.org Cc: Mike Christie <michael.christie@oracle.com> Subject: [PATCH v2 7/7] vhost-scsi: Reduce vhost_scsi_mutex use Date: Mon, 20 Mar 2023 21:06:24 -0500 [thread overview] Message-ID: <20230321020624.13323-8-michael.christie@oracle.com> (raw) In-Reply-To: <20230321020624.13323-1-michael.christie@oracle.com> We on longer need to hold the vhost_scsi_mutex the entire time we set/clear the endpoint. The tv_tpg_mutex handles tpg accesses not related to the tpg list, the port link/unlink functions use the tv_tpg_mutex while accessing the tpg->vhost_scsi pointer, vhost_scsi_do_plug will no longer queue events after the virtqueue's backend has been cleared and flushed, and we don't drop our refcount to the tpg until after we have stopped cmds and wait for outstanding cmds to complete. This moves the vhost_scsi_mutex use to it's documented use of being used to access the tpg list. We then don't need to hold it while a flush is being performed causing other device's vhost_scsi_set_endpoint and vhost_scsi_make_tpg/vhost_scsi_drop_tpg calls to have to wait on a flakey device. Signed-off-by: Mike Christie <michael.christie@oracle.com> --- drivers/vhost/scsi.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index d4372a4aff49..3b0b556c57ef 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -229,7 +229,10 @@ struct vhost_scsi_ctx { struct iov_iter out_iter; }; -/* Global spinlock to protect vhost_scsi TPG list for vhost IOCTL access */ +/* + * Global mutex to protect vhost_scsi TPG list for vhost IOCTLs and LIO + * configfs management operations. + */ static DEFINE_MUTEX(vhost_scsi_mutex); static LIST_HEAD(vhost_scsi_list); @@ -1526,7 +1529,7 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds) * vhost_scsi_tpg with an active struct vhost_scsi_nexus * * The lock nesting rule is: - * vhost_scsi_mutex -> vs->dev.mutex -> tpg->tv_tpg_mutex -> vq->mutex + * vs->dev.mutex -> vhost_scsi_mutex -> tpg->tv_tpg_mutex -> vq->mutex */ static int vhost_scsi_set_endpoint(struct vhost_scsi *vs, @@ -1540,7 +1543,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, int index, ret, i, len; bool match = false; - mutex_lock(&vhost_scsi_mutex); mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ @@ -1561,6 +1563,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (vs->vs_tpg) memcpy(vs_tpg, vs->vs_tpg, len); + mutex_lock(&vhost_scsi_mutex); list_for_each_entry(tpg, &vhost_scsi_list, tv_tpg_list) { mutex_lock(&tpg->tv_tpg_mutex); if (!tpg->tpg_nexus) { @@ -1576,6 +1579,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) { if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) { mutex_unlock(&tpg->tv_tpg_mutex); + mutex_unlock(&vhost_scsi_mutex); ret = -EEXIST; goto undepend; } @@ -1590,6 +1594,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, if (ret) { pr_warn("target_depend_item() failed: %d\n", ret); mutex_unlock(&tpg->tv_tpg_mutex); + mutex_unlock(&vhost_scsi_mutex); goto undepend; } tpg->tv_tpg_vhost_count++; @@ -1599,6 +1604,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, } mutex_unlock(&tpg->tv_tpg_mutex); } + mutex_unlock(&vhost_scsi_mutex); if (match) { memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn, @@ -1654,7 +1660,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, kfree(vs_tpg); out: mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return ret; } @@ -1670,7 +1675,6 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, int index, ret, i; u8 target; - mutex_lock(&vhost_scsi_mutex); mutex_lock(&vs->dev.mutex); /* Verify that ring has been setup correctly. */ for (index = 0; index < vs->dev.nvqs; ++index) { @@ -1757,12 +1761,10 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, vs->vs_tpg = NULL; WARN_ON(vs->vs_events_nr); mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return 0; err_dev: mutex_unlock(&vs->dev.mutex); - mutex_unlock(&vhost_scsi_mutex); return ret; } -- 2.25.1
next prev parent reply other threads:[~2023-03-21 2:06 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-21 2:06 [PATCH v2 0/7] vhost-scsi: Fix crashes and management op hangs Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` [PATCH v2 1/7] vhost-scsi: Fix vhost_scsi struct use after free Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` [PATCH v2 2/7] vhost-scsi: Fix crash during LUN unmapping Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` [PATCH v2 3/7] vhost-scsi: Delay releasing our refcount on the tpg Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` [PATCH v2 4/7] vhost-scsi: Drop device mutex use in vhost_scsi_do_plug Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` [PATCH v2 5/7] vhost-scsi: Check for a cleared backend before queueing an event Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` [PATCH v2 6/7] vhost-scsi: Drop vhost_scsi_mutex use in port callouts Mike Christie 2023-03-21 2:06 ` Mike Christie 2023-03-21 2:06 ` Mike Christie [this message] 2023-03-21 2:06 ` [PATCH v2 7/7] vhost-scsi: Reduce vhost_scsi_mutex use Mike Christie 2023-03-21 2:29 ` [PATCH v2 0/7] vhost-scsi: Fix crashes and management op hangs michael.christie 2023-03-21 2:29 ` michael.christie 2023-03-21 7:12 ` Michael S. Tsirkin 2023-03-21 7:12 ` Michael S. Tsirkin 2023-03-21 17:25 ` Mike Christie 2023-03-21 17:25 ` Mike Christie
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