1 files changed, 86 insertions, 166 deletions

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 6dabbdb66651..f84592345573 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -44,7 +44,6 @@
 #define P9_PORT 564
 #define MAX_SOCK_BUF (64*1024)
 #define ERREQFLUSH      1
-#define SCHED_TIMEOUT   10
 #define MAXPOLLWADDR    2
 
 /**
@@ -135,17 +134,16 @@ struct p9_req {
         struct list_head req_list;
 };
 
-struct p9_mux_poll_task {
-        struct task_struct *task;
-        struct list_head mux_list;
-        int muxnum;
+struct p9_poll_wait {
+        struct p9_conn *conn;
+        wait_queue_t wait;
+        wait_queue_head_t *wait_addr;
 };
 
 /**
  * struct p9_conn - fd mux connection state information
  * @lock: protects mux_list (?)
  * @mux_list: list link for mux to manage multiple connections (?)
- * @poll_task: task polling on this connection
  * @msize: maximum size for connection (dup)
  * @extended: 9p2000.u flag (dup)
  * @trans: reference to transport instance for this connection
@@ -171,7 +169,6 @@ struct p9_mux_poll_task {
 struct p9_conn {
         spinlock_t lock; /* protect lock structure */
         struct list_head mux_list;
-        struct p9_mux_poll_task *poll_task;
         int msize;
         unsigned char extended;
         struct p9_trans *trans;
@@ -185,8 +182,8 @@ struct p9_conn {
         int wpos;
         int wsize;
         char *wbuf;
-        wait_queue_t poll_wait[MAXPOLLWADDR];
-        wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
+        struct list_head poll_pending_link;
+        struct p9_poll_wait poll_wait[MAXPOLLWADDR];
         poll_table pt;
         struct work_struct rq;
         struct work_struct wq;
@@ -220,12 +217,10 @@ static void p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
 static int p9_fd_write(struct p9_trans *trans, void *v, int len);
 static int p9_fd_read(struct p9_trans *trans, void *v, int len);
 
-static DEFINE_MUTEX(p9_mux_task_lock);
+static DEFINE_SPINLOCK(p9_poll_lock);
+static LIST_HEAD(p9_poll_pending_list);
 static struct workqueue_struct *p9_mux_wq;
-
-static int p9_mux_num;
-static int p9_mux_poll_task_num;
-static struct p9_mux_poll_task p9_mux_poll_tasks[100];
+static struct task_struct *p9_poll_task;
 
 static void p9_conn_destroy(struct p9_conn *);
 static unsigned int p9_fd_poll(struct p9_trans *trans,
@@ -255,130 +250,23 @@ static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
                 p9_idpool_put(tag, m->tagpool);
 }
 
-/**
- * p9_mux_calc_poll_procs - calculates the number of polling procs
- * @muxnum: number of mounts
- *
- * Calculation is based on the number of mounted v9fs filesystems.
- * The current implementation returns sqrt of the number of mounts.
- */
-
-static int p9_mux_calc_poll_procs(int muxnum)
-{
-        int n;
-
-        if (p9_mux_poll_task_num)
-                n = muxnum / p9_mux_poll_task_num +
-                    (muxnum % p9_mux_poll_task_num ? 1 : 0);
-        else
-                n = 1;
-
-        if (n > ARRAY_SIZE(p9_mux_poll_tasks))
-                n = ARRAY_SIZE(p9_mux_poll_tasks);
-
-        return n;
-}
-
-static int p9_mux_poll_start(struct p9_conn *m)
+static void p9_mux_poll_stop(struct p9_conn *m)
 {
-        int i, n;
-        struct p9_mux_poll_task *vpt, *vptlast;
-        struct task_struct *pproc;
-
-        P9_DPRINTK(P9_DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, p9_mux_num,
-                p9_mux_poll_task_num);
-        mutex_lock(&p9_mux_task_lock);
-
-        n = p9_mux_calc_poll_procs(p9_mux_num + 1);
-        if (n > p9_mux_poll_task_num) {
-                for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
-                        if (p9_mux_poll_tasks[i].task == NULL) {
-                                vpt = &p9_mux_poll_tasks[i];
-                                P9_DPRINTK(P9_DEBUG_MUX, "create proc %p\n",
-                                                                        vpt);
-                                pproc = kthread_create(p9_poll_proc, vpt,
-                                                                "v9fs-poll");
-
-                                if (!IS_ERR(pproc)) {
-                                        vpt->task = pproc;
-                                        INIT_LIST_HEAD(&vpt->mux_list);
-                                        vpt->muxnum = 0;
-                                        p9_mux_poll_task_num++;
-                                        wake_up_process(vpt->task);
-                                }
-                                break;
-                        }
-                }
-
-                if (i >= ARRAY_SIZE(p9_mux_poll_tasks))
-                        P9_DPRINTK(P9_DEBUG_ERROR,
-                                        "warning: no free poll slots\n");
-        }
+        unsigned long flags;
+        int i;
 
-        n = (p9_mux_num + 1) / p9_mux_poll_task_num +
-            ((p9_mux_num + 1) % p9_mux_poll_task_num ? 1 : 0);
-
-        vptlast = NULL;
-        for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
-                vpt = &p9_mux_poll_tasks[i];
-                if (vpt->task != NULL) {
-                        vptlast = vpt;
-                        if (vpt->muxnum < n) {
-                                P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
-                                list_add(&m->mux_list, &vpt->mux_list);
-                                vpt->muxnum++;
-                                m->poll_task = vpt;
-                                memset(&m->poll_waddr, 0,
-                                                        sizeof(m->poll_waddr));
-                                init_poll_funcptr(&m->pt, p9_pollwait);
-                                break;
-                        }
-                }
-        }
+        for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
+                struct p9_poll_wait *pwait = &m->poll_wait[i];
 
-        if (i >= ARRAY_SIZE(p9_mux_poll_tasks)) {
-                if (vptlast == NULL) {
-                        mutex_unlock(&p9_mux_task_lock);
-                        return -ENOMEM;
+                if (pwait->wait_addr) {
+                        remove_wait_queue(pwait->wait_addr, &pwait->wait);
+                        pwait->wait_addr = NULL;
                 }
-
-                P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
-                list_add(&m->mux_list, &vptlast->mux_list);
-                vptlast->muxnum++;
-                m->poll_task = vptlast;
-                memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
-                init_poll_funcptr(&m->pt, p9_pollwait);
         }
 
-        p9_mux_num++;
-        mutex_unlock(&p9_mux_task_lock);
-
-        return 0;
-}
-
-static void p9_mux_poll_stop(struct p9_conn *m)
-{
-        int i;
-        struct p9_mux_poll_task *vpt;
-
-        mutex_lock(&p9_mux_task_lock);
-        vpt = m->poll_task;
-        list_del(&m->mux_list);
-        for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
-                if (m->poll_waddr[i] != NULL) {
-                        remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
-                        m->poll_waddr[i] = NULL;
-                }
-        }
-        vpt->muxnum--;
-        if (!vpt->muxnum) {
-                P9_DPRINTK(P9_DEBUG_MUX, "destroy proc %p\n", vpt);
-                kthread_stop(vpt->task);
-                vpt->task = NULL;
-                p9_mux_poll_task_num--;
-        }
-        p9_mux_num--;
-        mutex_unlock(&p9_mux_task_lock);
+        spin_lock_irqsave(&p9_poll_lock, flags);
+        list_del_init(&m->poll_pending_link);
+        spin_unlock_irqrestore(&p9_poll_lock, flags);
 }
 
 /**
@@ -414,11 +302,8 @@ static struct p9_conn *p9_conn_create(struct p9_trans *trans)
         INIT_LIST_HEAD(&m->unsent_req_list);
         INIT_WORK(&m->rq, p9_read_work);
         INIT_WORK(&m->wq, p9_write_work);
-        n = p9_mux_poll_start(m);
-        if (n) {
-                kfree(m);
-                return ERR_PTR(n);
-        }
+        INIT_LIST_HEAD(&m->poll_pending_link);
+        init_poll_funcptr(&m->pt, p9_pollwait);
 
         n = p9_fd_poll(trans, &m->pt);
         if (n & POLLIN) {
@@ -431,11 +316,12 @@ static struct p9_conn *p9_conn_create(struct p9_trans *trans)
                 set_bit(Wpending, &m->wsched);
         }
 
-        for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
-                if (IS_ERR(m->poll_waddr[i])) {
+        for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
+                if (IS_ERR(m->poll_wait[i].wait_addr)) {
                         p9_mux_poll_stop(m);
                         kfree(m);
-                        return (void *)m->poll_waddr;   /* the error code */
+                        /* return the error code */
+                        return (void *)m->poll_wait[i].wait_addr;
                 }
         }
 
@@ -464,6 +350,23 @@ static void p9_conn_destroy(struct p9_conn *m)
         kfree(m);
 }
 
+static int p9_pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+        struct p9_poll_wait *pwait =
+                container_of(wait, struct p9_poll_wait, wait);
+        struct p9_conn *m = pwait->conn;
+        unsigned long flags;
+        DECLARE_WAITQUEUE(dummy_wait, p9_poll_task);
+
+        spin_lock_irqsave(&p9_poll_lock, flags);
+        if (list_empty(&m->poll_pending_link))
+                list_add_tail(&m->poll_pending_link, &p9_poll_pending_list);
+        spin_unlock_irqrestore(&p9_poll_lock, flags);
+
+        /* perform the default wake up operation */
+        return default_wake_function(&dummy_wait, mode, sync, key);
+}
+
 /**
  * p9_pollwait - add poll task to the wait queue
  * @filp: file pointer being polled
@@ -476,29 +379,32 @@ static void p9_conn_destroy(struct p9_conn *m)
 static void
 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 {
+        struct p9_conn *m = container_of(p, struct p9_conn, pt);
+        struct p9_poll_wait *pwait = NULL;
         int i;
-        struct p9_conn *m;
 
-        m = container_of(p, struct p9_conn, pt);
-        for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
-                if (m->poll_waddr[i] == NULL)
+        for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
+                if (m->poll_wait[i].wait_addr == NULL) {
+                        pwait = &m->poll_wait[i];
                         break;
+                }
+        }
 
-        if (i >= ARRAY_SIZE(m->poll_waddr)) {
+        if (!pwait) {
                 P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
                 return;
         }
 
-        m->poll_waddr[i] = wait_address;
-
         if (!wait_address) {
                 P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
-                m->poll_waddr[i] = ERR_PTR(-EIO);
+                pwait->wait_addr = ERR_PTR(-EIO);
                 return;
         }
 
-        init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
-        add_wait_queue(wait_address, &m->poll_wait[i]);
+        pwait->conn = m;
+        pwait->wait_addr = wait_address;
+        init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
+        add_wait_queue(wait_address, &pwait->wait);
 }
 
 /**
@@ -553,23 +459,34 @@ static void p9_poll_mux(struct p9_conn *m)
 
 static int p9_poll_proc(void *a)
 {
-        struct p9_conn *m, *mtmp;
-        struct p9_mux_poll_task *vpt;
+        unsigned long flags;
 
-        vpt = a;
-        P9_DPRINTK(P9_DEBUG_MUX, "start %p %p\n", current, vpt);
-        while (!kthread_should_stop()) {
-                set_current_state(TASK_INTERRUPTIBLE);
+        P9_DPRINTK(P9_DEBUG_MUX, "start %p\n", current);
+ repeat:
+        spin_lock_irqsave(&p9_poll_lock, flags);
+        while (!list_empty(&p9_poll_pending_list)) {
+                struct p9_conn *conn = list_first_entry(&p9_poll_pending_list,
+                                                        struct p9_conn,
+                                                        poll_pending_link);
+                list_del_init(&conn->poll_pending_link);
+                spin_unlock_irqrestore(&p9_poll_lock, flags);
 
-                list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
-                        p9_poll_mux(m);
-                }
+                p9_poll_mux(conn);
 
-                P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
-                schedule_timeout(SCHED_TIMEOUT * HZ);
+                spin_lock_irqsave(&p9_poll_lock, flags);
         }
+        spin_unlock_irqrestore(&p9_poll_lock, flags);
 
+        set_current_state(TASK_INTERRUPTIBLE);
+        if (list_empty(&p9_poll_pending_list)) {
+                P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
+                schedule();
+        }
         __set_current_state(TASK_RUNNING);
+
+        if (!kthread_should_stop())
+                goto repeat;
+
         P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
         return 0;
 }
@@ -1602,17 +1519,19 @@ static struct p9_trans_module p9_fd_trans = {
 
 int p9_trans_fd_init(void)
 {
-        int i;
-
-        for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
-                p9_mux_poll_tasks[i].task = NULL;
-
         p9_mux_wq = create_workqueue("v9fs");
         if (!p9_mux_wq) {
                 printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
                 return -ENOMEM;
         }
 
+        p9_poll_task = kthread_run(p9_poll_proc, NULL, "v9fs-poll");
+        if (IS_ERR(p9_poll_task)) {
+                destroy_workqueue(p9_mux_wq);
+                printk(KERN_WARNING "v9fs: mux: creating poll task failed\n");
+                return PTR_ERR(p9_poll_task);
+        }
+
         v9fs_register_trans(&p9_tcp_trans);
         v9fs_register_trans(&p9_unix_trans);
         v9fs_register_trans(&p9_fd_trans);
@@ -1622,6 +1541,7 @@ int p9_trans_fd_init(void)
 
 void p9_trans_fd_exit(void)
 {
+        kthread_stop(p9_poll_task);
         v9fs_unregister_trans(&p9_tcp_trans);
         v9fs_unregister_trans(&p9_unix_trans);
         v9fs_unregister_trans(&p9_fd_trans);