9p: move request management to client code
[linux-2.6.git] / net / 9p / trans_virtio.c
index 72493f0..36bce45 100644 (file)
@@ -1,12 +1,10 @@
 /*
- * The Guest 9p transport driver
+ * The Virtio 9p transport driver
  *
  * This is a block based transport driver based on the lguest block driver
  * code.
  *
- */
-/*
- *  Copyright (C) 2007 Eric Van Hensbergen, IBM Corporation
+ *  Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation
  *
  *  Based on virtio console driver
  *  Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
@@ -54,49 +52,6 @@ static DEFINE_MUTEX(virtio_9p_lock);
 /* global which tracks highest initialized channel */
 static int chan_index;
 
-#define P9_INIT_MAXTAG 16
-
-/**
- * enum p9_req_status_t - virtio request status
- * @REQ_STATUS_IDLE: request slot unused
- * @REQ_STATUS_SENT: request sent to server
- * @REQ_STATUS_RCVD: response received from server
- * @REQ_STATUS_FLSH: request has been flushed
- *
- * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
- * but use is actually tracked by the idpool structure which handles tag
- * id allocation.
- *
- */
-
-enum p9_req_status_t {
-       REQ_STATUS_IDLE,
-       REQ_STATUS_SENT,
-       REQ_STATUS_RCVD,
-       REQ_STATUS_FLSH,
-};
-
-/**
- * struct p9_req_t - virtio request slots
- * @status: status of this request slot
- * @wq: wait_queue for the client to block on for this request
- *
- * The virtio transport uses an array to track outstanding requests
- * instead of a list.  While this may incurr overhead during initial
- * allocation or expansion, it makes request lookup much easier as the
- * tag id is a index into an array.  (We use tag+1 so that we can accomodate
- * the -1 tag for the T_VERSION request).
- * This also has the nice effect of only having to allocate wait_queues
- * once, instead of constantly allocating and freeing them.  Its possible
- * other resources could benefit from this scheme as well.
- *
- */
-
-struct p9_req_t {
-       int status;
-       wait_queue_head_t *wq;
-};
-
 /**
  * struct virtio_chan - per-instance transport information
  * @initialized: whether the channel is initialized
@@ -121,67 +76,14 @@ static struct virtio_chan {
 
        spinlock_t lock;
 
+       struct p9_client *client;
        struct virtio_device *vdev;
        struct virtqueue *vq;
 
-       struct p9_idpool *tagpool;
-       struct p9_req_t *reqs;
-       int max_tag;
-
        /* Scatterlist: can be too big for stack. */
        struct scatterlist sg[VIRTQUEUE_NUM];
 } channels[MAX_9P_CHAN];
 
-/**
- * p9_lookup_tag - Lookup requests by tag
- * @c: virtio channel to lookup tag within
- * @tag: numeric id for transaction
- *
- * this is a simple array lookup, but will grow the
- * request_slots as necessary to accomodate transaction
- * ids which did not previously have a slot.
- *
- * Bugs: there is currently no upper limit on request slots set
- * here, but that should be constrained by the id accounting.
- */
-
-static struct p9_req_t *p9_lookup_tag(struct virtio_chan *c, u16 tag)
-{
-       /* This looks up the original request by tag so we know which
-        * buffer to read the data into */
-       tag++;
-
-       while (tag >= c->max_tag) {
-               int old_max = c->max_tag;
-               int count;
-
-               if (c->max_tag)
-                       c->max_tag *= 2;
-               else
-                       c->max_tag = P9_INIT_MAXTAG;
-
-               c->reqs = krealloc(c->reqs, sizeof(struct p9_req_t)*c->max_tag,
-                                                               GFP_ATOMIC);
-               if (!c->reqs) {
-                       printk(KERN_ERR "Couldn't grow tag array\n");
-                       BUG();
-               }
-               for (count = old_max; count < c->max_tag; count++) {
-                       c->reqs[count].status = REQ_STATUS_IDLE;
-                       c->reqs[count].wq = kmalloc(sizeof(wait_queue_head_t),
-                                                               GFP_ATOMIC);
-                       if (!c->reqs[count].wq) {
-                               printk(KERN_ERR "Couldn't grow tag array\n");
-                               BUG();
-                       }
-                       init_waitqueue_head(c->reqs[count].wq);
-               }
-       }
-
-       return &c->reqs[tag];
-}
-
-
 /* How many bytes left in this page. */
 static unsigned int rest_of_page(void *data)
 {
@@ -200,22 +102,10 @@ static unsigned int rest_of_page(void *data)
 static void p9_virtio_close(struct p9_client *client)
 {
        struct virtio_chan *chan = client->trans;
-       int count;
-       unsigned long flags;
-
-       spin_lock_irqsave(&chan->lock, flags);
-       p9_idpool_destroy(chan->tagpool);
-       for (count = 0; count < chan->max_tag; count++)
-               kfree(chan->reqs[count].wq);
-       kfree(chan->reqs);
-       chan->max_tag = 0;
-       spin_unlock_irqrestore(&chan->lock, flags);
 
        mutex_lock(&virtio_9p_lock);
        chan->inuse = false;
        mutex_unlock(&virtio_9p_lock);
-
-       client->trans = NULL;
 }
 
 /**
@@ -241,7 +131,7 @@ static void req_done(struct virtqueue *vq)
 
        spin_lock_irqsave(&chan->lock, flags);
        while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) {
-               req = p9_lookup_tag(chan, rc->tag);
+               req = p9_tag_lookup(chan->client, rc->tag);
                req->status = REQ_STATUS_RCVD;
                wake_up(req->wq);
        }
@@ -311,13 +201,13 @@ p9_virtio_rpc(struct p9_client *c, struct p9_fcall *tc, struct p9_fcall **rc)
 
        n = P9_NOTAG;
        if (tc->id != P9_TVERSION) {
-               n = p9_idpool_get(chan->tagpool);
+               n = p9_idpool_get(c->tagpool);
                if (n < 0)
                        return -ENOMEM;
        }
 
        spin_lock_irqsave(&chan->lock, flags);
-       req = p9_lookup_tag(chan, n);
+       req = p9_tag_alloc(c, n);
        spin_unlock_irqrestore(&chan->lock, flags);
 
        p9_set_tag(tc, n);
@@ -357,8 +247,8 @@ p9_virtio_rpc(struct p9_client *c, struct p9_fcall *tc, struct p9_fcall **rc)
        }
 #endif
 
-       if (n != P9_NOTAG && p9_idpool_check(n, chan->tagpool))
-               p9_idpool_put(n, chan->tagpool);
+       if (n != P9_NOTAG && p9_idpool_check(n, c->tagpool))
+               p9_idpool_put(n, c->tagpool);
 
        req->status = REQ_STATUS_IDLE;
 
@@ -463,16 +353,8 @@ p9_virtio_create(struct p9_client *client, const char *devname, char *args)
                return -ENODEV;
        }
 
-       chan->tagpool = p9_idpool_create();
-       if (IS_ERR(chan->tagpool)) {
-               printk(KERN_ERR "9p: couldn't allocate tagpool\n");
-               return -ENOMEM;
-       }
-       p9_idpool_get(chan->tagpool); /* reserve tag 0 */
-       chan->max_tag = 0;
-       chan->reqs = NULL;
-
        client->trans = (void *)chan;
+       chan->client = client;
 
        return 0;
 }