diff options
Diffstat (limited to 'net/9p/trans_virtio.c')
| -rw-r--r-- | net/9p/trans_virtio.c | 136 |
1 files changed, 9 insertions, 127 deletions
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 72493f0..36bce45 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -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; } |
