9p: use the rcall structure passed in the request in trans_fd read_work

This patch reworks the read_work function to enable it to directly use a passed
in rcall structure.  This should help allow us to remove unnecessary copies
in the future.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index cc9bc73..627e3f0 100644 (file)
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -111,7 +111,9 @@ struct p9_poll_wait {
  * @err: error state
  * @req_list: accounting for requests which have been sent
  * @unsent_req_list: accounting for requests that haven't been sent
- * @rcall: current response &p9_fcall structure
+ * @req: current request being processed (if any)
+ * @tmp_buf: temporary buffer to read in header
+ * @rsize: amount to read for current frame
  * @rpos: read position in current frame
  * @rbuf: current read buffer
  * @wpos: write position for current frame
@@ -132,7 +134,9 @@ struct p9_conn {
        int err;
        struct list_head req_list;
        struct list_head unsent_req_list;
-       struct p9_fcall *rcall;
+       struct p9_req_t *req;
+       char tmp_buf[7];
+       int rsize;
        int rpos;
        char *rbuf;
        int wpos;
@@ -346,34 +350,25 @@ static void p9_read_work(struct work_struct *work)
 {
        int n, err;
        struct p9_conn *m;
-       struct p9_req_t *req;
-       struct p9_fcall *rcall;
-       char *rbuf;
 
        m = container_of(work, struct p9_conn, rq);
 
        if (m->err < 0)
                return;
 
-       rcall = NULL;
        P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
 
-       if (!m->rcall) {
-               m->rcall =
-                   kmalloc(sizeof(struct p9_fcall) + m->client->msize,
-                                                               GFP_KERNEL);
-               if (!m->rcall) {
-                       err = -ENOMEM;
-                       goto error;
-               }
-
-               m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
+       if (!m->rbuf) {
+               m->rbuf = m->tmp_buf;
                m->rpos = 0;
+               m->rsize = 7; /* start by reading header */
        }
 
        clear_bit(Rpending, &m->wsched);
+       P9_DPRINTK(P9_DEBUG_MUX, "read mux %p pos %d size: %d = %d\n", m,
+                                       m->rpos, m->rsize, m->rsize-m->rpos);
        err = p9_fd_read(m->client, m->rbuf + m->rpos,
-                                               m->client->msize - m->rpos);
+                                               m->rsize - m->rpos);
        P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
        if (err == -EAGAIN) {
                clear_bit(Rworksched, &m->wsched);
@@ -384,8 +379,12 @@ static void p9_read_work(struct work_struct *work)
                goto error;
 
        m->rpos += err;
-       while (m->rpos > 4) {
-               n = le32_to_cpu(*(__le32 *) m->rbuf);
+
+       if ((!m->req) && (m->rpos == m->rsize)) { /* header read in */
+               u16 tag;
+               P9_DPRINTK(P9_DEBUG_MUX, "got new header\n");
+
+               n = le32_to_cpu(*(__le32 *) m->rbuf); /* read packet size */
                if (n >= m->client->msize) {
                        P9_DPRINTK(P9_DEBUG_ERROR,
                                "requested packet size too big: %d\n", n);
@@ -393,66 +392,71 @@ static void p9_read_work(struct work_struct *work)
                        goto error;
                }
 
-               if (m->rpos < n)
-                       break;
+               tag = le16_to_cpu(*(__le16 *) (m->rbuf+5)); /* read tag */
+               P9_DPRINTK(P9_DEBUG_MUX, "mux %p pkt: size: %d bytes tag: %d\n",
+                                                                m, n, tag);
 
-               err =
-                   p9_deserialize_fcall(m->rbuf, n, m->rcall, m->client->dotu);
-               if (err < 0)
+               m->req = p9_tag_lookup(m->client, tag);
+               if (!m->req) {
+                       P9_DPRINTK(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",
+                                                                tag);
+                       err = -EIO;
                        goto error;
+               }
+
+               if (m->req->rc == NULL) {
+                       m->req->rc = kmalloc(sizeof(struct p9_fcall) +
+                                               m->client->msize, GFP_KERNEL);
+                       if (!m->req->rc) {
+                               m->req = NULL;
+                               err = -ENOMEM;
+                               goto error;
+                       }
+               }
+               m->rbuf = (char *)m->req->rc + sizeof(struct p9_fcall);
+               memcpy(m->rbuf, m->tmp_buf, m->rsize);
+               m->rsize = n;
+       }
+
+       /* not an else because some packets (like clunk) have no payload */
+       if ((m->req) && (m->rpos == m->rsize)) { /* packet is read in */
+               P9_DPRINTK(P9_DEBUG_MUX, "got new packet\n");
+               m->rbuf = (char *)m->req->rc + sizeof(struct p9_fcall);
+               err = p9_deserialize_fcall(m->rbuf, m->rsize, m->req->rc,
+                                                       m->client->dotu);
+               if (err < 0) {
+                       m->req = NULL;
+                       goto error;
+               }
 
 #ifdef CONFIG_NET_9P_DEBUG
                if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
                        char buf[150];
 
-                       p9_printfcall(buf, sizeof(buf), m->rcall,
+                       p9_printfcall(buf, sizeof(buf), m->req->rc,
                                m->client->dotu);
                        printk(KERN_NOTICE ">>> %p %s\n", m, buf);
                }
 #endif
 
-               rcall = m->rcall;
-               rbuf = m->rbuf;
-               if (m->rpos > n) {
-                       m->rcall = kmalloc(sizeof(struct p9_fcall) +
-                                               m->client->msize, GFP_KERNEL);
-                       if (!m->rcall) {
-                               err = -ENOMEM;
-                               goto error;
-                       }
+               P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
+                                       m->req->rc->id, m->req->rc->tag);
 
-                       m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
-                       memmove(m->rbuf, rbuf + n, m->rpos - n);
-                       m->rpos -= n;
-               } else {
-                       m->rcall = NULL;
-                       m->rbuf = NULL;
-                       m->rpos = 0;
-               }
+               m->rbuf = NULL;
+               m->rpos = 0;
+               m->rsize = 0;
 
-               P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
-                                                       rcall->id, rcall->tag);
+               if (m->req->status != REQ_STATUS_FLSH) {
+                       list_del(&m->req->req_list);
+                       m->req->status = REQ_STATUS_RCVD;
+               }
 
-               req = p9_tag_lookup(m->client, rcall->tag);
+               process_request(m, m->req);
 
-               if (req) {
-                       if (req->status != REQ_STATUS_FLSH) {
-                               list_del(&req->req_list);
-                               req->status = REQ_STATUS_RCVD;
-                       }
+               if (m->req->status != REQ_STATUS_FLSH)
+                       p9_conn_rpc_cb(m->client, m->req);
 
-                       req->rc = rcall;
-                       process_request(m, req);
-
-                       if (req->status != REQ_STATUS_FLSH)
-                               p9_conn_rpc_cb(m->client, req);
-               } else {
-                       if (err >= 0 && rcall->id != P9_RFLUSH)
-                               P9_DPRINTK(P9_DEBUG_ERROR,
-                                 "unexpected response mux %p id %d tag %d\n",
-                                 m, rcall->id, rcall->tag);
-                       kfree(rcall);
-               }
+               m->req = NULL;
        }
 
        if (!list_empty(&m->req_list)) {
@@ -470,7 +474,6 @@ static void p9_read_work(struct work_struct *work)
                clear_bit(Rworksched, &m->wsched);
 
        return;
-
 error:
        p9_conn_cancel(m, err);
        clear_bit(Rworksched, &m->wsched);