From 101998f6fcd680ed12d85633b81504feb1cb0667 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Mon, 30 Jul 2012 13:30:00 -0700 Subject: 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: Michael S. Tsirkin Cc: Michael S. Tsirkin Cc: Stefan Hajnoczi Cc: Anthony Liguori Cc: Zhi Yong Wu Cc: Paolo Bonzini Signed-off-by: Nicholas Bellinger --- drivers/vhost/tcm_vhost.c | 195 +++++++++++++++++++++++++--------------------- drivers/vhost/tcm_vhost.h | 9 ++- 2 files changed, 111 insertions(+), 93 deletions(-) (limited to 'drivers') diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index 481af88..74b2eda 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -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; diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h index c983ed2..eff42df 100644 --- a/drivers/vhost/tcm_vhost.h +++ b/drivers/vhost/tcm_vhost.h @@ -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) -- cgit v1.1