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Subject[PATCH] 9p: trans_fd, read rework to use p9_parse_header
Date
Most of the changes here are no-op and just renaming to use a
fcall struct, needed for p9_parse_header

It fixes the unaligned memory access to read the tag and defers to
common functions for part of the protocol knowledge (although header
length is still hard-coded...)

Reported-By: Rob Landley <rob@landley.net>
Signed-Off-By: Dominique Martinet <dominique.martinet@cea.fr>
---
net/9p/trans_fd.c | 75 +++++++++++++++++++++++++++++--------------------------
1 file changed, 40 insertions(+), 35 deletions(-)

It ended up alot bigger than I thought it'd be, submitting it anyway
but happy with either version - letting Eric decide what's better :)

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index bced8c0..a270dcc 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -108,9 +108,7 @@ struct p9_poll_wait {
* @unsent_req_list: accounting for requests that haven't been sent
* @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
+ * @rc: temporary fcall for reading current frame
* @wpos: write position for current frame
* @wsize: amount of data to write for current frame
* @wbuf: current write buffer
@@ -131,9 +129,7 @@ struct p9_conn {
struct list_head unsent_req_list;
struct p9_req_t *req;
char tmp_buf[7];
- int rsize;
- int rpos;
- char *rbuf;
+ struct p9_fcall rc;
int wpos;
int wsize;
char *wbuf;
@@ -305,49 +301,56 @@ static void p9_read_work(struct work_struct *work)
if (m->err < 0)
return;

- p9_debug(P9_DEBUG_TRANS, "start mux %p pos %d\n", m, m->rpos);
+ p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset);

- if (!m->rbuf) {
- m->rbuf = m->tmp_buf;
- m->rpos = 0;
- m->rsize = 7; /* start by reading header */
+ if (!m->rc.sdata) {
+ m->rc.sdata = m->tmp_buf;
+ m->rc.offset = 0;
+ m->rc.capacity = 7; /* start by reading header */
}

clear_bit(Rpending, &m->wsched);
- p9_debug(P9_DEBUG_TRANS, "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->rsize - m->rpos);
+ p9_debug(P9_DEBUG_TRANS, "read mux %p pos %zd size: %zd = %zd\n",
+ m, m->rc.offset, m->rc.capacity,
+ m->rc.capacity - m->rc.offset);
+ err = p9_fd_read(m->client, m->rc.sdata + m->rc.offset,
+ m->rc.capacity - m->rc.offset);
p9_debug(P9_DEBUG_TRANS, "mux %p got %d bytes\n", m, err);
- if (err == -EAGAIN) {
+ if (err == -EAGAIN)
goto end_clear;
- }

if (err <= 0)
goto error;

- m->rpos += err;
+ m->rc.offset += err;

- if ((!m->req) && (m->rpos == m->rsize)) { /* header read in */
- u16 tag;
+ /* header read in */
+ if ((!m->req) && (m->rc.offset == m->rc.capacity)) {
p9_debug(P9_DEBUG_TRANS, "got new header\n");

- n = le32_to_cpu(*(__le32 *) m->rbuf); /* read packet size */
- if (n >= m->client->msize) {
+ err = p9_parse_header(&m->rc, NULL, NULL, NULL, 0);
+ if (err) {
p9_debug(P9_DEBUG_ERROR,
- "requested packet size too big: %d\n", n);
+ "error parsing header: %d\n", err);
+ goto error;
+ }
+
+ if (m->rc.size >= m->client->msize) {
+ p9_debug(P9_DEBUG_ERROR,
+ "requested packet size too big: %d\n",
+ m->rc.size);
err = -EIO;
goto error;
}

- tag = le16_to_cpu(*(__le16 *) (m->rbuf+5)); /* read tag */
p9_debug(P9_DEBUG_TRANS,
- "mux %p pkt: size: %d bytes tag: %d\n", m, n, tag);
+ "mux %p pkt: size: %d bytes tag: %d\n",
+ m, m->rc.size, m->rc.tag);

- m->req = p9_tag_lookup(m->client, tag);
+ m->req = p9_tag_lookup(m->client, m->rc.tag);
if (!m->req || (m->req->status != REQ_STATUS_SENT)) {
p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",
- tag);
+ m->rc.tag);
err = -EIO;
goto error;
}
@@ -361,13 +364,15 @@ static void p9_read_work(struct work_struct *work)
goto error;
}
}
- m->rbuf = (char *)m->req->rc + sizeof(struct p9_fcall);
- memcpy(m->rbuf, m->tmp_buf, m->rsize);
- m->rsize = n;
+ m->rc.sdata = (char *)m->req->rc + sizeof(struct p9_fcall);
+ memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity);
+ m->rc.capacity = m->rc.size;
}

- /* not an else because some packets (like clunk) have no payload */
- if ((m->req) && (m->rpos == m->rsize)) { /* packet is read in */
+ /* packet is read in
+ * not an else because some packets (like clunk) have no payload
+ */
+ if ((m->req) && (m->rc.offset == m->rc.capacity)) {
p9_debug(P9_DEBUG_TRANS, "got new packet\n");
spin_lock(&m->client->lock);
if (m->req->status != REQ_STATUS_ERROR)
@@ -375,9 +380,9 @@ static void p9_read_work(struct work_struct *work)
list_del(&m->req->req_list);
spin_unlock(&m->client->lock);
p9_client_cb(m->client, m->req, status);
- m->rbuf = NULL;
- m->rpos = 0;
- m->rsize = 0;
+ m->rc.sdata = NULL;
+ m->rc.offset = 0;
+ m->rc.capacity = 0;
m->req = NULL;
}

--
1.8.3.1


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