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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2011-08-17 16:56:04 +0000 |
|---|---|---|
| committer | Eric Van Hensbergen <ericvh@gmail.com> | 2011-09-06 08:17:15 -0500 |
| commit | b49d8b5d7007a673796f3f99688b46931293873e (patch) | |
| tree | d798935e0149fca46b4a08ba219f716ec9abd520 /net/9p | |
| parent | 45089142b1497dab2327d60f6c71c40766fc3ea4 (diff) | |
| download | lwn-b49d8b5d7007a673796f3f99688b46931293873e.tar.gz lwn-b49d8b5d7007a673796f3f99688b46931293873e.zip | |
net/9p: Fix kernel crash with msize 512K
With msize equal to 512K (PAGE_SIZE * VIRTQUEUE_NUM), we hit multiple
crashes. This patch fix those.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Diffstat (limited to 'net/9p')
| -rw-r--r-- | net/9p/trans_virtio.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 175b5135bdcf..e317583fcc73 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -263,7 +263,6 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req) { int in, out, inp, outp; struct virtio_chan *chan = client->trans; - char *rdata = (char *)req->rc+sizeof(struct p9_fcall); unsigned long flags; size_t pdata_off = 0; struct trans_rpage_info *rpinfo = NULL; @@ -346,7 +345,8 @@ req_retry_pinned: * 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); + inp = pack_sg_list(chan->sg, out, + VIRTQUEUE_NUM, req->rc->sdata, 11); /* * Running executables in the filesystem may result in * a read request with kernel buffer as opposed to user buffer. @@ -366,8 +366,8 @@ req_retry_pinned: } in += inp; } else { - in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata, - req->rc->capacity); + in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, + req->rc->sdata, req->rc->capacity); } err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc); @@ -592,7 +592,14 @@ static struct p9_trans_module p9_virtio_trans = { .close = p9_virtio_close, .request = p9_virtio_request, .cancel = p9_virtio_cancel, - .maxsize = PAGE_SIZE*VIRTQUEUE_NUM, + + /* + * We leave one entry for input and one entry for response + * headers. We also skip one more entry to accomodate, address + * that are not at page boundary, that can result in an extra + * page in zero copy. + */ + .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3), .pref = P9_TRANS_PREF_PAYLOAD_SEP, .def = 0, .owner = THIS_MODULE, |