On Thu, 10 Feb 2011 17:25:08 -0800, "Venkateswararao Jujjuri (JV)" <jvrao@xxxxxxxxxxxxxxxxxx> wrote:
> Signed-off-by: Venkateswararao Jujjuri <jvrao@xxxxxxxxxxxxxxxxxx>
Can we remove the checks for request type in p9_virtio_request. Current
we have
p9_client_read()
{
if (zero coy enabled) {
...
} else {
.....
}
}
Then again in p9_virtio_request
p9_virtio_request()
{
if (request->id == P9_TREAD)
}
It would be nice if we can avoid doing that request->id check in
p9_virtio_request. So that if we want to add zero copy for any other
type of request we won't need to change p9_virtio_rquest.
-aneesh
> ---
> net/9p/trans_virtio.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++---
> 1 files changed, 101 insertions(+), 6 deletions(-)
>
> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
> index c8f3f72..e0c301f 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);
> @@ -202,6 +211,30 @@ static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
> return 1;
> }
>
> +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
> @@ -212,22 +245,82 @@ 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 && !segment_eq(get_fs(), KERNEL_DS))) {
> + 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_KERNEL);
> + 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);
> - 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);
> +
> + /* Handle out VirtIO ring buffers */
> + if (req->tc->pbuf_size && (req->tc->id == P9_TWRITE)) {
> + /* We have additional write payload buffer to take care */
> + out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata,
> + req->tc->size);
> + outp = pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
> + pdata_off, rpinfo->rp_data, pdata_len);
> + out += outp;
> + } else {
> + out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata,
> + req->tc->size);
> + }
> +
> + /* Handle in VirtIO ring buffers */
> + if (req->tc->pbuf_size && (req->tc->id == P9_TREAD)) {
> + /* We have additional Read payload buffer to take care */
> + 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 && !segment_eq(get_fs(), KERNEL_DS)) {
> + 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, 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 +339,8 @@ req_retry:
> P9_DPRINTK(P9_DEBUG_TRANS,
> "9p debug: "
> "virtio rpc add_buf returned failure");
> + if (rpinfo && rpinfo->rp_alloc)
> + kfree(rpinfo);
> return -EIO;
> }
> }
> --
> 1.6.5.2
>
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