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Commit 101998f6 authored by Nicholas Bellinger's avatar Nicholas Bellinger
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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
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Showing with 111 additions and 93 deletions
drivers/vhost/tcm_vhost.c
View file @ 101998f6
......@@ -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
View file @ 101998f6
......@@ -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)
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