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Commit 101998f6 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

tcm_vhost: Post-merge review changes requested by MST 



This patch contains the post RFC-v5 (post-merge) changes, this includes:

- Add locking comment
- Move vhost_scsi_complete_cmd ahead of TFO callbacks in order to
  drop forward declarations
- Drop extra '!= NULL' usage in vhost_scsi_complete_cmd_work()
- Change vhost_scsi_*_handle_kick() to use pr_debug
- Fix possible race in vhost_scsi_set_endpoint() for vs->vs_tpg checking
  + assignment.
- Convert tv_tpg->tpg_vhost_count + ->tv_tpg_port_count from atomic_t ->
  int, and make sure reference is protected by ->tv_tpg_mutex.
- Drop unnecessary vhost_scsi->vhost_ref_cnt
- Add 'err:' label for exception path in vhost_scsi_clear_endpoint()
- Add enum for VQ numbers, add usage in vhost_scsi_open()
- Add vhost_scsi_flush() + vhost_scsi_flush_vq() following
  drivers/vhost/net.c
- Add smp_wmb() + vhost_scsi_flush() call during vhost_scsi_set_features()
- Drop unnecessary copy_from_user() usage with GET_ABI_VERSION ioctl
- Add missing vhost_scsi_compat_ioctl() caller for vhost_scsi_fops
- Fix function parameter definition first line to follow existing
  vhost code style
- Change 'vHost' usage -> 'vhost' in handful of locations
- Change -EPERM -> -EBUSY usage for two failures in tcm_vhost_drop_nexus()
- Add comment for tcm_vhost_workqueue in tcm_vhost_init()
- Make GET_ABI_VERSION return 'int' + add comment in tcm_vhost.h

Reported-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Zhi Yong Wu <wuzhy@cn.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent f0e0e9bb

drivers/vhost/tcm_vhost.c

+106 −89
Original line number Diff line number Diff line
@@ -53,9 +53,14 @@ 
#include "vhost.h"

#include "tcm_vhost.h"



enum {

	VHOST_SCSI_VQ_CTL = 0,

	VHOST_SCSI_VQ_EVT = 1,

	VHOST_SCSI_VQ_IO = 2,

};



struct vhost_scsi {

	atomic_t vhost_ref_cnt;

	struct tcm_vhost_tpg *vs_tpg;

	struct tcm_vhost_tpg *vs_tpg;	/* Protected by vhost_scsi->dev.mutex */

	struct vhost_dev dev;

	struct vhost_virtqueue vqs[3];
@@ -131,8 +136,7 @@ static u32 tcm_vhost_get_default_depth(struct se_portal_group *se_tpg) 
	return 1;

}



static u32 tcm_vhost_get_pr_transport_id(

	struct se_portal_group *se_tpg,

static u32 tcm_vhost_get_pr_transport_id(struct se_portal_group *se_tpg,

	struct se_node_acl *se_nacl,

	struct t10_pr_registration *pr_reg,

	int *format_code,
@@ -162,8 +166,7 @@ static u32 tcm_vhost_get_pr_transport_id( 
			format_code, buf);

}



static u32 tcm_vhost_get_pr_transport_id_len(

	struct se_portal_group *se_tpg,

static u32 tcm_vhost_get_pr_transport_id_len(struct se_portal_group *se_tpg,

	struct se_node_acl *se_nacl,

	struct t10_pr_registration *pr_reg,

	int *format_code)
@@ -192,8 +195,7 @@ static u32 tcm_vhost_get_pr_transport_id_len( 
			format_code);

}



static char *tcm_vhost_parse_pr_out_transport_id(

	struct se_portal_group *se_tpg,

static char *tcm_vhost_parse_pr_out_transport_id(struct se_portal_group *se_tpg,

	const char *buf,

	u32 *out_tid_len,

	char **port_nexus_ptr)
@@ -236,8 +238,7 @@ static struct se_node_acl *tcm_vhost_alloc_fabric_acl( 
	return &nacl->se_node_acl;

}



static void tcm_vhost_release_fabric_acl(

	struct se_portal_group *se_tpg,

static void tcm_vhost_release_fabric_acl(struct se_portal_group *se_tpg,

	struct se_node_acl *se_nacl)

{

	struct tcm_vhost_nacl *nacl = container_of(se_nacl,
@@ -297,7 +298,16 @@ static int tcm_vhost_get_cmd_state(struct se_cmd *se_cmd) 
	return 0;

}



static void vhost_scsi_complete_cmd(struct tcm_vhost_cmd *);

static void vhost_scsi_complete_cmd(struct tcm_vhost_cmd *tv_cmd)

{

	struct vhost_scsi *vs = tv_cmd->tvc_vhost;



	spin_lock_bh(&vs->vs_completion_lock);

	list_add_tail(&tv_cmd->tvc_completion_list, &vs->vs_completion_list);

	spin_unlock_bh(&vs->vs_completion_lock);



	vhost_work_queue(&vs->dev, &vs->vs_completion_work);

}



static int tcm_vhost_queue_data_in(struct se_cmd *se_cmd)

{
@@ -381,7 +391,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) 
					vs_completion_work);

	struct tcm_vhost_cmd *tv_cmd;



	while ((tv_cmd = vhost_scsi_get_cmd_from_completion(vs)) != NULL) {

	while ((tv_cmd = vhost_scsi_get_cmd_from_completion(vs))) {

		struct virtio_scsi_cmd_resp v_rsp;

		struct se_cmd *se_cmd = &tv_cmd->tvc_se_cmd;

		int ret;
@@ -408,19 +418,6 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) 
	vhost_signal(&vs->dev, &vs->vqs[2]);

}



static void vhost_scsi_complete_cmd(struct tcm_vhost_cmd *tv_cmd)

{

	struct vhost_scsi *vs = tv_cmd->tvc_vhost;



	pr_debug("%s tv_cmd %p\n", __func__, tv_cmd);



	spin_lock_bh(&vs->vs_completion_lock);

	list_add_tail(&tv_cmd->tvc_completion_list, &vs->vs_completion_list);

	spin_unlock_bh(&vs->vs_completion_lock);



	vhost_work_queue(&vs->dev, &vs->vs_completion_work);

}



static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd(

	struct tcm_vhost_tpg *tv_tpg,

	struct virtio_scsi_cmd_req *v_req,
@@ -787,12 +784,12 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs) 


static void vhost_scsi_ctl_handle_kick(struct vhost_work *work)

{

	pr_err("%s: The handling func for control queue.\n", __func__);

	pr_debug("%s: The handling func for control queue.\n", __func__);

}



static void vhost_scsi_evt_handle_kick(struct vhost_work *work)

{

	pr_err("%s: The handling func for event queue.\n", __func__);

	pr_debug("%s: The handling func for event queue.\n", __func__);

}



static void vhost_scsi_handle_kick(struct vhost_work *work)
@@ -825,11 +822,6 @@ static int vhost_scsi_set_endpoint( 
			return -EFAULT;

		}

	}



	if (vs->vs_tpg) {

		mutex_unlock(&vs->dev.mutex);

		return -EEXIST;

	}

	mutex_unlock(&vs->dev.mutex);



	mutex_lock(&tcm_vhost_mutex);
@@ -839,7 +831,7 @@ static int vhost_scsi_set_endpoint( 
			mutex_unlock(&tv_tpg->tv_tpg_mutex);

			continue;

		}

		if (atomic_read(&tv_tpg->tv_tpg_vhost_count)) {

		if (tv_tpg->tv_tpg_vhost_count != 0) {

			mutex_unlock(&tv_tpg->tv_tpg_mutex);

			continue;

		}
@@ -847,14 +839,20 @@ static int vhost_scsi_set_endpoint( 


		if (!strcmp(tv_tport->tport_name, t->vhost_wwpn) &&

		    (tv_tpg->tport_tpgt == t->vhost_tpgt)) {

			atomic_inc(&tv_tpg->tv_tpg_vhost_count);

			smp_mb__after_atomic_inc();

			tv_tpg->tv_tpg_vhost_count++;

			mutex_unlock(&tv_tpg->tv_tpg_mutex);

			mutex_unlock(&tcm_vhost_mutex);



			mutex_lock(&vs->dev.mutex);

			if (vs->vs_tpg) {

				mutex_unlock(&vs->dev.mutex);

				mutex_lock(&tv_tpg->tv_tpg_mutex);

				tv_tpg->tv_tpg_vhost_count--;

				mutex_unlock(&tv_tpg->tv_tpg_mutex);

				return -EEXIST;

			}



			vs->vs_tpg = tv_tpg;

			atomic_inc(&vs->vhost_ref_cnt);

			smp_mb__after_atomic_inc();

			mutex_unlock(&vs->dev.mutex);

			return 0;
@@ -871,38 +869,42 @@ static int vhost_scsi_clear_endpoint( 
{

	struct tcm_vhost_tport *tv_tport;

	struct tcm_vhost_tpg *tv_tpg;

	int index;

	int index, ret;



	mutex_lock(&vs->dev.mutex);

	/* Verify that ring has been setup correctly. */

	for (index = 0; index < vs->dev.nvqs; ++index) {

		if (!vhost_vq_access_ok(&vs->vqs[index])) {

			mutex_unlock(&vs->dev.mutex);

			return -EFAULT;

			ret = -EFAULT;

			goto err;

		}

	}



	if (!vs->vs_tpg) {

		mutex_unlock(&vs->dev.mutex);

		return -ENODEV;

		ret = -ENODEV;

		goto err;

	}

	tv_tpg = vs->vs_tpg;

	tv_tport = tv_tpg->tport;



	if (strcmp(tv_tport->tport_name, t->vhost_wwpn) ||

	    (tv_tpg->tport_tpgt != t->vhost_tpgt)) {

		mutex_unlock(&vs->dev.mutex);

		pr_warn("tv_tport->tport_name: %s, tv_tpg->tport_tpgt: %hu"

			" does not match t->vhost_wwpn: %s, t->vhost_tpgt: %hu\n",

			tv_tport->tport_name, tv_tpg->tport_tpgt,

			t->vhost_wwpn, t->vhost_tpgt);

		return -EINVAL;

		ret = -EINVAL;

		goto err;

	}

	atomic_dec(&tv_tpg->tv_tpg_vhost_count);

	tv_tpg->tv_tpg_vhost_count--;

	vs->vs_tpg = NULL;

	mutex_unlock(&vs->dev.mutex);



	return 0;



err:

	mutex_unlock(&vs->dev.mutex);

	return ret;

}



static int vhost_scsi_open(struct inode *inode, struct file *f)
@@ -918,9 +920,9 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) 
	INIT_LIST_HEAD(&s->vs_completion_list);

	spin_lock_init(&s->vs_completion_lock);



	s->vqs[0].handle_kick = vhost_scsi_ctl_handle_kick;

	s->vqs[1].handle_kick = vhost_scsi_evt_handle_kick;

	s->vqs[2].handle_kick = vhost_scsi_handle_kick;

	s->vqs[VHOST_SCSI_VQ_CTL].handle_kick = vhost_scsi_ctl_handle_kick;

	s->vqs[VHOST_SCSI_VQ_EVT].handle_kick = vhost_scsi_evt_handle_kick;

	s->vqs[VHOST_SCSI_VQ_IO].handle_kick = vhost_scsi_handle_kick;

	r = vhost_dev_init(&s->dev, s->vqs, 3);

	if (r < 0) {

		kfree(s);
@@ -949,6 +951,18 @@ static int vhost_scsi_release(struct inode *inode, struct file *f) 
	return 0;

}



static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index)

{

	vhost_poll_flush(&vs->dev.vqs[index].poll);

}



static void vhost_scsi_flush(struct vhost_scsi *vs)

{

	vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_CTL);

	vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_EVT);

	vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_IO);

}



static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features)

{

	if (features & ~VHOST_FEATURES)
@@ -961,7 +975,8 @@ static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) 
		return -EFAULT;

	}

	vs->dev.acked_features = features;

	/* TODO possibly smp_wmb() and flush vqs */

	smp_wmb();

	vhost_scsi_flush(vs);

	mutex_unlock(&vs->dev.mutex);

	return 0;

}
@@ -974,7 +989,7 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl, 
	void __user *argp = (void __user *)arg;

	u64 __user *featurep = argp;

	u64 features;

	int r;

	int r, abi_version = VHOST_SCSI_ABI_VERSION;



	switch (ioctl) {

	case VHOST_SCSI_SET_ENDPOINT:
@@ -988,12 +1003,7 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl, 


		return vhost_scsi_clear_endpoint(vs, &backend);

	case VHOST_SCSI_GET_ABI_VERSION:

		if (copy_from_user(&backend, argp, sizeof backend))

			return -EFAULT;



		backend.abi_version = VHOST_SCSI_ABI_VERSION;



		if (copy_to_user(argp, &backend, sizeof backend))

		if (copy_to_user(argp, &abi_version, sizeof abi_version))

			return -EFAULT;

		return 0;

	case VHOST_GET_FEATURES:
@@ -1013,11 +1023,21 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl, 
	}

}



#ifdef CONFIG_COMPAT

static long vhost_scsi_compat_ioctl(struct file *f, unsigned int ioctl,

				unsigned long arg)

{

	return vhost_scsi_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));

}

#endif



static const struct file_operations vhost_scsi_fops = {

	.owner          = THIS_MODULE,

	.release        = vhost_scsi_release,

	.unlocked_ioctl = vhost_scsi_ioctl,

	/* TODO compat ioctl? */

#ifdef CONFIG_COMPAT

	.compat_ioctl	= vhost_scsi_compat_ioctl,

#endif

	.open           = vhost_scsi_open,

	.llseek		= noop_llseek,

};
@@ -1054,28 +1074,28 @@ static char *tcm_vhost_dump_proto_id(struct tcm_vhost_tport *tport) 
	return "Unknown";

}



static int tcm_vhost_port_link(

	struct se_portal_group *se_tpg,

static int tcm_vhost_port_link(struct se_portal_group *se_tpg,

	struct se_lun *lun)

{

	struct tcm_vhost_tpg *tv_tpg = container_of(se_tpg,

				struct tcm_vhost_tpg, se_tpg);



	atomic_inc(&tv_tpg->tv_tpg_port_count);

	smp_mb__after_atomic_inc();

	mutex_lock(&tv_tpg->tv_tpg_mutex);

	tv_tpg->tv_tpg_port_count++;

	mutex_unlock(&tv_tpg->tv_tpg_mutex);



	return 0;

}



static void tcm_vhost_port_unlink(

	struct se_portal_group *se_tpg,

static void tcm_vhost_port_unlink(struct se_portal_group *se_tpg,

	struct se_lun *se_lun)

{

	struct tcm_vhost_tpg *tv_tpg = container_of(se_tpg,

				struct tcm_vhost_tpg, se_tpg);



	atomic_dec(&tv_tpg->tv_tpg_port_count);

	smp_mb__after_atomic_dec();

	mutex_lock(&tv_tpg->tv_tpg_mutex);

	tv_tpg->tv_tpg_port_count--;

	mutex_unlock(&tv_tpg->tv_tpg_mutex);

}



static struct se_node_acl *tcm_vhost_make_nodeacl(
@@ -1122,8 +1142,7 @@ static void tcm_vhost_drop_nodeacl(struct se_node_acl *se_acl) 
	kfree(nacl);

}



static int tcm_vhost_make_nexus(

	struct tcm_vhost_tpg *tv_tpg,

static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tv_tpg,

	const char *name)

{

	struct se_portal_group *se_tpg;
@@ -1168,7 +1187,7 @@ static int tcm_vhost_make_nexus( 
		return -ENOMEM;

	}

	/*

	 * Now register the TCM vHost virtual I_T Nexus as active with the

	 * Now register the TCM vhost virtual I_T Nexus as active with the

	 * call to __transport_register_session()

	 */

	__transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
@@ -1179,8 +1198,7 @@ static int tcm_vhost_make_nexus( 
	return 0;

}



static int tcm_vhost_drop_nexus(

	struct tcm_vhost_tpg *tpg)

static int tcm_vhost_drop_nexus(struct tcm_vhost_tpg *tpg)

{

	struct se_session *se_sess;

	struct tcm_vhost_nexus *tv_nexus;
@@ -1198,27 +1216,27 @@ static int tcm_vhost_drop_nexus( 
		return -ENODEV;

	}



	if (atomic_read(&tpg->tv_tpg_port_count)) {

	if (tpg->tv_tpg_port_count != 0) {

		mutex_unlock(&tpg->tv_tpg_mutex);

		pr_err("Unable to remove TCM_vHost I_T Nexus with"

		pr_err("Unable to remove TCM_vhost I_T Nexus with"

			" active TPG port count: %d\n",

			atomic_read(&tpg->tv_tpg_port_count));

		return -EPERM;

			tpg->tv_tpg_port_count);

		return -EBUSY;

	}



	if (atomic_read(&tpg->tv_tpg_vhost_count)) {

	if (tpg->tv_tpg_vhost_count != 0) {

		mutex_unlock(&tpg->tv_tpg_mutex);

		pr_err("Unable to remove TCM_vHost I_T Nexus with"

		pr_err("Unable to remove TCM_vhost I_T Nexus with"

			" active TPG vhost count: %d\n",

			atomic_read(&tpg->tv_tpg_vhost_count));

		return -EPERM;

			tpg->tv_tpg_vhost_count);

		return -EBUSY;

	}



	pr_debug("TCM_vHost_ConfigFS: Removing I_T Nexus to emulated"

	pr_debug("TCM_vhost_ConfigFS: Removing I_T Nexus to emulated"

		" %s Initiator Port: %s\n", tcm_vhost_dump_proto_id(tpg->tport),

		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);

	/*

	 * Release the SCSI I_T Nexus to the emulated vHost Target Port

	 * Release the SCSI I_T Nexus to the emulated vhost Target Port

	 */

	transport_deregister_session(tv_nexus->tvn_se_sess);

	tpg->tpg_nexus = NULL;
@@ -1228,8 +1246,7 @@ static int tcm_vhost_drop_nexus( 
	return 0;

}



static ssize_t tcm_vhost_tpg_show_nexus(

	struct se_portal_group *se_tpg,

static ssize_t tcm_vhost_tpg_show_nexus(struct se_portal_group *se_tpg,

	char *page)

{

	struct tcm_vhost_tpg *tv_tpg = container_of(se_tpg,
@@ -1250,8 +1267,7 @@ static ssize_t tcm_vhost_tpg_show_nexus( 
	return ret;

}



static ssize_t tcm_vhost_tpg_store_nexus(

	struct se_portal_group *se_tpg,

static ssize_t tcm_vhost_tpg_store_nexus(struct se_portal_group *se_tpg,

	const char *page,

	size_t count)

{
@@ -1336,8 +1352,7 @@ static struct configfs_attribute *tcm_vhost_tpg_attrs[] = { 
	NULL,

};



static struct se_portal_group *tcm_vhost_make_tpg(

	struct se_wwn *wwn,

static struct se_portal_group *tcm_vhost_make_tpg(struct se_wwn *wwn,

	struct config_group *group,

	const char *name)

{
@@ -1385,7 +1400,7 @@ static void tcm_vhost_drop_tpg(struct se_portal_group *se_tpg) 
	list_del(&tpg->tv_tpg_list);

	mutex_unlock(&tcm_vhost_mutex);

	/*

	 * Release the virtual I_T Nexus for this vHost TPG

	 * Release the virtual I_T Nexus for this vhost TPG

	 */

	tcm_vhost_drop_nexus(tpg);

	/*
@@ -1395,8 +1410,7 @@ static void tcm_vhost_drop_tpg(struct se_portal_group *se_tpg) 
	kfree(tpg);

}



static struct se_wwn *tcm_vhost_make_tport(

	struct target_fabric_configfs *tf,

static struct se_wwn *tcm_vhost_make_tport(struct target_fabric_configfs *tf,

	struct config_group *group,

	const char *name)

{
@@ -1592,7 +1606,10 @@ static void tcm_vhost_deregister_configfs(void) 
static int __init tcm_vhost_init(void)

{

	int ret = -ENOMEM;



	/*

	 * Use our own dedicated workqueue for submitting I/O into

	 * target core to avoid contention within system_wq.

	 */

	tcm_vhost_workqueue = alloc_workqueue("tcm_vhost", 0, 0);

	if (!tcm_vhost_workqueue)

		goto out;

drivers/vhost/tcm_vhost.h

+5 −4
Original line number Diff line number Diff line
@@ -47,9 +47,9 @@ struct tcm_vhost_tpg { 
	/* Vhost port target portal group tag for TCM */

	u16 tport_tpgt;

	/* Used to track number of TPG Port/Lun Links wrt to explict I_T Nexus shutdown */

	atomic_t tv_tpg_port_count;

	/* Used for vhost_scsi device reference to tpg_nexus */

	atomic_t tv_tpg_vhost_count;

	int tv_tpg_port_count;

	/* Used for vhost_scsi device reference to tpg_nexus, protected by tv_tpg_mutex */

	int tv_tpg_vhost_count;

	/* list for tcm_vhost_list */

	struct list_head tv_tpg_list;

	/* Used to protect access for tpg_nexus */
@@ -98,4 +98,5 @@ struct vhost_scsi_target { 
/* VHOST_SCSI specific defines */

#define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct vhost_scsi_target)

#define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct vhost_scsi_target)

#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, struct vhost_scsi_target)
 
/* Changing this breaks userspace. */

#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, int)