This patch adds necessary infrastructure for placing page addresses
directly on the sg list for the server to consume.
The newly added routine pack_sg_list_p() is just like pack_sg_list()
except that it takes page array as an input and directly places them on
the sg list after taking care of the first page offset.
Signed-off-by: Venkateswararao Jujjuri <jvrao@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Badari Pulavarty <pbadari@xxxxxxxxxx>
---
include/net/9p/9p.h | 6 ++++-
net/9p/client.c | 4 +++
net/9p/trans_virtio.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 65 insertions(+), 4 deletions(-)
diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index a8de812..382ef22 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -651,7 +651,11 @@ struct p9_fcall {
size_t offset;
size_t capacity;
-
+ struct page **pdata;
+ uint32_t pdata_mapped_pages;
+ uint32_t pdata_off;
+ uint32_t pdata_write_len;
+ uint32_t pdata_read_len;
uint8_t *sdata;
};
diff --git a/net/9p/client.c b/net/9p/client.c
index 29bbbbd..5487896 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -244,8 +244,12 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
}
req->tc->sdata = (char *) req->tc + sizeof(struct p9_fcall);
req->tc->capacity = c->msize;
+ req->tc->pdata_write_len = 0;
+ req->tc->pdata_read_len = 0;
req->rc->sdata = (char *) req->rc + sizeof(struct p9_fcall);
req->rc->capacity = c->msize;
+ req->rc->pdata_write_len = 0;
+ req->rc->pdata_read_len = 0;
}
p9pdu_reset(req->tc);
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 762c19f..8f86cb5 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -180,6 +180,44 @@ pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
return index-start;
}
+/**
+ * pack_sg_list_p - Pack a scatter gather list from an array of pages.
+ * @sg: scatter/gather list to pack into
+ * @start: which segment of the sg_list to start at
+ * @limit: maximum segment to pack data to
+ * @pdu: pdu prepared to put on the wire.
+ * @count: amount of data to pack into the scatter/gather list
+ *
+ * This is just like pack_sg_list() except that it takes page array
+ * as an input and directly places them on the sg list after taking
+ * care of the first page offset.
+ */
+
+static int
+pack_sg_list_p(struct scatterlist *sg, int start, int limit,
+ struct p9_fcall *pdu, int count)
+{
+ int s;
+ int i = 0;
+ int index = start;
+
+ if (pdu->pdata_off) {
+ s = min((int)(PAGE_SIZE - pdu->pdata_off), count);
+ sg_set_page(&sg[index++], pdu->pdata[i++], s, pdu->pdata_off);
+ count -= s;
+ }
+
+ while (count) {
+ BUG_ON(index > limit);
+ s = min((int)PAGE_SIZE, count);
+ sg_set_page(&sg[index++], pdu->pdata[i++], s, 0);
+ count -= s;
+ }
+
+ return index-start;
+}
+
+
/* We don't currently allow canceling of virtio requests */
static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
{
@@ -196,16 +234,31 @@ 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, outp, inp;
struct virtio_chan *chan = client->trans;
char *rdata = (char *)req->rc+sizeof(struct p9_fcall);
P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n");
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,
+ req->tc->size);
+
+ BUG_ON(req->tc->pdata_write_len && req->tc->pdata_read_len);
+
+ if (req->tc->pdata_write_len) {
+ outp = pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
+ req->tc, req->tc->pdata_write_len);
+ out += outp;
+ }
+ if (req->tc->pdata_read_len) {
+ inp = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata, 11);
+ in = pack_sg_list_p(chan->sg, out+inp, VIRTQUEUE_NUM,
+ req->tc, req->tc->pdata_read_len);
+ in += inp;
+ } else {
+ in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata,
client->msize);
+ }
req->status = REQ_STATUS_SENT;
--
1.6.5.2
--
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