diff options
| -rw-r--r-- | net/9p/trans_common.h | 3 | ||||
| -rw-r--r-- | net/9p/trans_virtio.c | 128 |
2 files changed, 126 insertions, 5 deletions
diff --git a/net/9p/trans_common.h b/net/9p/trans_common.h index 04977e0ad93..76309223bb0 100644 --- a/net/9p/trans_common.h +++ b/net/9p/trans_common.h @@ -12,6 +12,9 @@ * */ +/* TRUE if it is user context */ +#define P9_IS_USER_CONTEXT (!segment_eq(get_fs(), KERNEL_DS)) + /** * struct trans_rpage_info - To store mapped page information in PDU. * @rp_alloc:Set if this structure is allocd, not a reuse unused space in pdu. diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index c8f3f72ab20..4b236de132d 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -45,6 +45,7 @@ #include <linux/scatterlist.h> #include <linux/virtio.h> #include <linux/virtio_9p.h> +#include "trans_common.h" #define VIRTQUEUE_NUM 128 @@ -155,6 +156,14 @@ static void req_done(struct virtqueue *vq) rc->tag); req = p9_tag_lookup(chan->client, rc->tag); req->status = REQ_STATUS_RCVD; + if (req->tc->private) { + struct trans_rpage_info *rp = req->tc->private; + /*Release pages */ + p9_release_req_pages(rp); + if (rp->rp_alloc) + kfree(rp); + req->tc->private = NULL; + } p9_client_cb(chan->client, req); } else { spin_unlock_irqrestore(&chan->lock, flags); @@ -203,6 +212,38 @@ static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) } /** + * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, + * this takes a list of pages. + * @sg: scatter/gather list to pack into + * @start: which segment of the sg_list to start at + * @pdata_off: Offset into the first page + * @**pdata: a list of pages to add into sg. + * @count: amount of data to pack into the scatter/gather list + */ +static int +pack_sg_list_p(struct scatterlist *sg, int start, int limit, size_t pdata_off, + struct page **pdata, int count) +{ + int s; + int i = 0; + int index = start; + + if (pdata_off) { + s = min((int)(PAGE_SIZE - pdata_off), count); + sg_set_page(&sg[index++], pdata[i++], s, pdata_off); + count -= s; + } + + while (count) { + BUG_ON(index > limit); + s = min((int)PAGE_SIZE, count); + sg_set_page(&sg[index++], pdata[i++], s, 0); + count -= s; + } + return index-start; +} + +/** * p9_virtio_request - issue a request * @client: client instance issuing the request * @req: request to be issued @@ -212,22 +253,97 @@ static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) static int p9_virtio_request(struct p9_client *client, struct p9_req_t *req) { - int in, out; + int in, out, inp, outp; struct virtio_chan *chan = client->trans; char *rdata = (char *)req->rc+sizeof(struct p9_fcall); unsigned long flags; - int err; + size_t pdata_off = 0; + struct trans_rpage_info *rpinfo = NULL; + int err, pdata_len = 0; P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n"); req_retry: req->status = REQ_STATUS_SENT; + if (req->tc->pbuf_size && (req->tc->pubuf && P9_IS_USER_CONTEXT)) { + int nr_pages = p9_nr_pages(req); + int rpinfo_size = sizeof(struct trans_rpage_info) + + sizeof(struct page *) * nr_pages; + + if (rpinfo_size <= (req->tc->capacity - req->tc->size)) { + /* We can use sdata */ + req->tc->private = req->tc->sdata + req->tc->size; + rpinfo = (struct trans_rpage_info *)req->tc->private; + rpinfo->rp_alloc = 0; + } else { + req->tc->private = kmalloc(rpinfo_size, GFP_NOFS); + if (!req->tc->private) { + P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: " + "private kmalloc returned NULL"); + return -ENOMEM; + } + rpinfo = (struct trans_rpage_info *)req->tc->private; + rpinfo->rp_alloc = 1; + } + + err = p9_payload_gup(req, &pdata_off, &pdata_len, nr_pages, + req->tc->id == P9_TREAD ? 1 : 0); + if (err < 0) { + if (rpinfo->rp_alloc) + kfree(rpinfo); + return err; + } + } + spin_lock_irqsave(&chan->lock, flags); + + /* Handle out VirtIO ring buffers */ out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata, - req->tc->size); - in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata, - client->msize); + req->tc->size); + + if (req->tc->pbuf_size && (req->tc->id == P9_TWRITE)) { + /* We have additional write payload buffer to take care */ + if (req->tc->pubuf && P9_IS_USER_CONTEXT) { + outp = pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM, + pdata_off, rpinfo->rp_data, pdata_len); + } else { + char *pbuf = req->tc->pubuf ? req->tc->pubuf : + req->tc->pkbuf; + outp = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, pbuf, + req->tc->pbuf_size); + } + out += outp; + } + + /* Handle in VirtIO ring buffers */ + if (req->tc->pbuf_size && + ((req->tc->id == P9_TREAD) || (req->tc->id == P9_TREADDIR))) { + /* + * Take care of additional Read payload. + * 11 is the read/write header = PDU Header(7) + IO Size (4). + * Arrange in such a way that server places header in the + * alloced memory and payload onto the user buffer. + */ + inp = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata, 11); + /* + * Running executables in the filesystem may result in + * a read request with kernel buffer as opposed to user buffer. + */ + if (req->tc->pubuf && P9_IS_USER_CONTEXT) { + in = pack_sg_list_p(chan->sg, out+inp, VIRTQUEUE_NUM, + pdata_off, rpinfo->rp_data, pdata_len); + } else { + char *pbuf = req->tc->pubuf ? req->tc->pubuf : + req->tc->pkbuf; + in = pack_sg_list(chan->sg, out+inp, VIRTQUEUE_NUM, + pbuf, req->tc->pbuf_size); + } + in += inp; + } else { + in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata, + client->msize); + } err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc); if (err < 0) { @@ -246,6 +362,8 @@ req_retry: P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: " "virtio rpc add_buf returned failure"); + if (rpinfo && rpinfo->rp_alloc) + kfree(rpinfo); return -EIO; } } |