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[SPARC64]: Fix race between MD update and dr-cpu add.
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We need to make sure the MD update occurs before we try to
process dr-cpu configure requests.  MD update and dr-cpu
were being processed by seperate threads so that did not
happen occaisionally.

Fix this by executing all domain services data packets from
a single thread, in order.

This will help simplify some other things as well.

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Jul 17, 2007
1 parent 3ac66e3 commit 778feeb
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Showing 2 changed files with 147 additions and 143 deletions.
270 changes: 140 additions & 130 deletions arch/sparc64/kernel/ds.c
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Original file line number Diff line number Diff line change
Expand Up @@ -228,7 +228,7 @@ static struct ds_cap_state *find_cap_by_string(const char *name)
return NULL;
}

static int ds_send(struct ldc_channel *lp, void *data, int len)
static int __ds_send(struct ldc_channel *lp, void *data, int len)
{
int err, limit = 1000;

Expand All @@ -243,6 +243,18 @@ static int ds_send(struct ldc_channel *lp, void *data, int len)
return err;
}

static int ds_send(struct ldc_channel *lp, void *data, int len)
{
unsigned long flags;
int err;

spin_lock_irqsave(&ds_lock, flags);
err = __ds_send(lp, data, len);
spin_unlock_irqrestore(&ds_lock, flags);

return err;
}

struct ds_md_update_req {
__u64 req_num;
};
Expand All @@ -267,6 +279,8 @@ static void md_update_data(struct ldc_channel *lp,

printk(KERN_INFO PFX "Machine description update.\n");

mdesc_update();

memset(&pkt, 0, sizeof(pkt));
pkt.data.tag.type = DS_DATA;
pkt.data.tag.len = sizeof(pkt) - sizeof(struct ds_msg_tag);
Expand All @@ -275,8 +289,6 @@ static void md_update_data(struct ldc_channel *lp,
pkt.res.result = DS_OK;

ds_send(lp, &pkt, sizeof(pkt));

mdesc_update();
}

struct ds_shutdown_req {
Expand Down Expand Up @@ -391,18 +403,6 @@ struct dr_cpu_resp_entry {
__u32 str_off;
};

/* DR cpu requests get queued onto the work list by the
* dr_cpu_data() callback. The list is protected by
* ds_lock, and processed by dr_cpu_process() in order.
*/
static LIST_HEAD(dr_cpu_work_list);
static DECLARE_WAIT_QUEUE_HEAD(dr_cpu_wait);

struct dr_cpu_queue_entry {
struct list_head list;
char req[0];
};

static void __dr_cpu_send_error(struct ds_cap_state *cp, struct ds_data *data)
{
struct dr_cpu_tag *tag = (struct dr_cpu_tag *) (data + 1);
Expand All @@ -425,7 +425,7 @@ static void __dr_cpu_send_error(struct ds_cap_state *cp, struct ds_data *data)

pkt.data.tag.len = msg_len - sizeof(struct ds_msg_tag);

ds_send(dp->lp, &pkt, msg_len);
__ds_send(dp->lp, &pkt, msg_len);
}

static void dr_cpu_send_error(struct ds_cap_state *cp, struct ds_data *data)
Expand Down Expand Up @@ -555,7 +555,7 @@ static int dr_cpu_configure(struct ds_cap_state *cp, u64 req_num,
}

spin_lock_irqsave(&ds_lock, flags);
ds_send(ds_info->lp, resp, resp_len);
__ds_send(ds_info->lp, resp, resp_len);
spin_unlock_irqrestore(&ds_lock, flags);

kfree(resp);
Expand Down Expand Up @@ -596,115 +596,57 @@ static int dr_cpu_unconfigure(struct ds_cap_state *cp, u64 req_num,
}

spin_lock_irqsave(&ds_lock, flags);
ds_send(ds_info->lp, resp, resp_len);
__ds_send(ds_info->lp, resp, resp_len);
spin_unlock_irqrestore(&ds_lock, flags);

kfree(resp);

return 0;
}

static void process_dr_cpu_list(struct ds_cap_state *cp)
static void dr_cpu_data(struct ldc_channel *lp,
struct ds_cap_state *cp,
void *buf, int len)
{
struct dr_cpu_queue_entry *qp, *tmp;
unsigned long flags;
LIST_HEAD(todo);
struct ds_data *data = buf;
struct dr_cpu_tag *tag = (struct dr_cpu_tag *) (data + 1);
u32 *cpu_list = (u32 *) (tag + 1);
u64 req_num = tag->req_num;
cpumask_t mask;
unsigned int i;
int err;

spin_lock_irqsave(&ds_lock, flags);
list_splice(&dr_cpu_work_list, &todo);
INIT_LIST_HEAD(&dr_cpu_work_list);
spin_unlock_irqrestore(&ds_lock, flags);

list_for_each_entry_safe(qp, tmp, &todo, list) {
struct ds_data *data = (struct ds_data *) qp->req;
struct dr_cpu_tag *tag = (struct dr_cpu_tag *) (data + 1);
u32 *cpu_list = (u32 *) (tag + 1);
u64 req_num = tag->req_num;
unsigned int i;
int err;

switch (tag->type) {
case DR_CPU_CONFIGURE:
case DR_CPU_UNCONFIGURE:
case DR_CPU_FORCE_UNCONFIGURE:
break;

default:
dr_cpu_send_error(cp, data);
goto next;
}

purge_dups(cpu_list, tag->num_records);

cpus_clear(mask);
for (i = 0; i < tag->num_records; i++) {
if (cpu_list[i] == CPU_SENTINEL)
continue;

if (cpu_list[i] < NR_CPUS)
cpu_set(cpu_list[i], mask);
}

if (tag->type == DR_CPU_CONFIGURE)
err = dr_cpu_configure(cp, req_num, &mask);
else
err = dr_cpu_unconfigure(cp, req_num, &mask);

if (err)
dr_cpu_send_error(cp, data);
switch (tag->type) {
case DR_CPU_CONFIGURE:
case DR_CPU_UNCONFIGURE:
case DR_CPU_FORCE_UNCONFIGURE:
break;

next:
list_del(&qp->list);
kfree(qp);
default:
dr_cpu_send_error(cp, data);
return;
}
}

static int dr_cpu_thread(void *__unused)
{
struct ds_cap_state *cp;
DEFINE_WAIT(wait);
purge_dups(cpu_list, tag->num_records);

cp = find_cap_by_string("dr-cpu");

while (1) {
prepare_to_wait(&dr_cpu_wait, &wait, TASK_INTERRUPTIBLE);
if (list_empty(&dr_cpu_work_list))
schedule();
finish_wait(&dr_cpu_wait, &wait);

if (kthread_should_stop())
break;
cpus_clear(mask);
for (i = 0; i < tag->num_records; i++) {
if (cpu_list[i] == CPU_SENTINEL)
continue;

process_dr_cpu_list(cp);
if (cpu_list[i] < NR_CPUS)
cpu_set(cpu_list[i], mask);
}

return 0;
}

static void dr_cpu_data(struct ldc_channel *lp,
struct ds_cap_state *dp,
void *buf, int len)
{
struct dr_cpu_queue_entry *qp;
struct ds_data *dpkt = buf;
struct dr_cpu_tag *rp;
if (tag->type == DR_CPU_CONFIGURE)
err = dr_cpu_configure(cp, req_num, &mask);
else
err = dr_cpu_unconfigure(cp, req_num, &mask);

rp = (struct dr_cpu_tag *) (dpkt + 1);

qp = kmalloc(sizeof(struct dr_cpu_queue_entry) + len, GFP_ATOMIC);
if (!qp) {
struct ds_cap_state *cp;

cp = find_cap_by_string("dr-cpu");
__dr_cpu_send_error(cp, dpkt);
} else {
memcpy(&qp->req, buf, len);
list_add_tail(&qp->list, &dr_cpu_work_list);
wake_up(&dr_cpu_wait);
}
if (err)
dr_cpu_send_error(cp, data);
}
#endif
#endif /* CONFIG_HOTPLUG_CPU */

struct ds_pri_msg {
__u64 req_num;
Expand Down Expand Up @@ -820,7 +762,7 @@ void ldom_set_var(const char *var, const char *value)
ds_var_doorbell = 0;
ds_var_response = -1;

ds_send(dp->lp, &pkt, msg_len);
__ds_send(dp->lp, &pkt, msg_len);
spin_unlock_irqrestore(&ds_lock, flags);

loops = 1000;
Expand Down Expand Up @@ -904,7 +846,7 @@ static int register_services(struct ds_info *dp)
pbuf.req.minor = 0;
strcpy(pbuf.req.svc_id, cp->service_id);

err = ds_send(lp, &pbuf, msg_len);
err = __ds_send(lp, &pbuf, msg_len);
if (err > 0)
cp->state = CAP_STATE_REG_SENT;
}
Expand Down Expand Up @@ -960,27 +902,97 @@ static int ds_handshake(struct ds_info *dp, struct ds_msg_tag *pkt)
return -ECONNRESET;
}

static void __send_ds_nack(struct ds_info *dp, u64 handle)
{
struct ds_data_nack nack = {
.tag = {
.type = DS_NACK,
.len = (sizeof(struct ds_data_nack) -
sizeof(struct ds_msg_tag)),
},
.handle = handle,
.result = DS_INV_HDL,
};

__ds_send(dp->lp, &nack, sizeof(nack));
}

static LIST_HEAD(ds_work_list);
static DECLARE_WAIT_QUEUE_HEAD(ds_wait);

struct ds_queue_entry {
struct list_head list;
int req_len;
int __pad;
u64 req[0];
};

static void process_ds_work(void)
{
struct ds_queue_entry *qp, *tmp;
static struct ds_info *dp;
unsigned long flags;
LIST_HEAD(todo);

spin_lock_irqsave(&ds_lock, flags);
list_splice(&ds_work_list, &todo);
INIT_LIST_HEAD(&ds_work_list);
spin_unlock_irqrestore(&ds_lock, flags);

dp = ds_info;

list_for_each_entry_safe(qp, tmp, &todo, list) {
struct ds_data *dpkt = (struct ds_data *) qp->req;
struct ds_cap_state *cp = find_cap(dpkt->handle);
int req_len = qp->req_len;

if (!cp) {
printk(KERN_ERR PFX "Data for unknown handle %lu\n",
dpkt->handle);

spin_lock_irqsave(&ds_lock, flags);
__send_ds_nack(dp, dpkt->handle);
spin_unlock_irqrestore(&ds_lock, flags);
} else {
cp->data(dp->lp, cp, dpkt, req_len);
}

list_del(&qp->list);
kfree(qp);
}
}

static int ds_thread(void *__unused)
{
DEFINE_WAIT(wait);

while (1) {
prepare_to_wait(&ds_wait, &wait, TASK_INTERRUPTIBLE);
if (list_empty(&ds_work_list))
schedule();
finish_wait(&ds_wait, &wait);

if (kthread_should_stop())
break;

process_ds_work();
}

return 0;
}

static int ds_data(struct ds_info *dp, struct ds_msg_tag *pkt, int len)
{
struct ds_data *dpkt = (struct ds_data *) pkt;
struct ds_cap_state *cp = find_cap(dpkt->handle);

if (!cp) {
struct ds_data_nack nack = {
.tag = {
.type = DS_NACK,
.len = (sizeof(struct ds_data_nack) -
sizeof(struct ds_msg_tag)),
},
.handle = dpkt->handle,
.result = DS_INV_HDL,
};

printk(KERN_ERR PFX "Data for unknown handle %lu\n",
dpkt->handle);
ds_send(dp->lp, &nack, sizeof(nack));
struct ds_queue_entry *qp;

qp = kmalloc(sizeof(struct ds_queue_entry) + len, GFP_ATOMIC);
if (!qp) {
__send_ds_nack(dp, dpkt->handle);
} else {
cp->data(dp->lp, cp, dpkt, len);
memcpy(&qp->req, pkt, len);
list_add_tail(&qp->list, &ds_work_list);
wake_up(&ds_wait);
}
return 0;
}
Expand All @@ -996,7 +1008,7 @@ static void ds_up(struct ds_info *dp)
req.ver.major = 1;
req.ver.minor = 0;

err = ds_send(lp, &req, sizeof(req));
err = __ds_send(lp, &req, sizeof(req));
if (err > 0)
dp->hs_state = DS_HS_START;
}
Expand Down Expand Up @@ -1148,9 +1160,7 @@ static int __init ds_init(void)
for (i = 0; i < ARRAY_SIZE(ds_states); i++)
ds_states[i].handle = ((u64)i << 32);

#ifdef CONFIG_HOTPLUG_CPU
kthread_run(dr_cpu_thread, NULL, "kdrcpud");
#endif
kthread_run(ds_thread, NULL, "kldomd");

return vio_register_driver(&ds_driver);
}
Expand Down
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