Re: [RFC-V3 7/7] [net/9p] Handle TREAD/RERROR case in !dotl case.

["Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com>]

On Thu, 10 Feb 2011 17:25:11 -0800, "Venkateswararao Jujjuri (JV)" <jvrao@linux.vnet.ibm.com> wrote:
> In addition, this patch also avoids zero copy for short reads in !dotl case.
> 
> Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
> ---
>  net/9p/client.c |   64 +++++++++++++++++++++++++++++++++++-------------------
>  1 files changed, 41 insertions(+), 23 deletions(-)
> 
> diff --git a/net/9p/client.c b/net/9p/client.c
> index f6d8531..3e51273 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -443,6 +443,7 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
>  {
>  	int8_t type;
>  	int err;
> +	int ecode;
> 
>  	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
>  	if (err) {
> @@ -450,36 +451,53 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
>  		return err;
>  	}
> 
> -	if (type == P9_RERROR || type == P9_RLERROR) {
> -		int ecode;
> -
> -		if (!p9_is_proto_dotl(c)) {
> -			char *ename;
> +	if (type != P9_RERROR && type != P9_RLERROR)
> +		return 0;
> 
> -			err = p9pdu_readf(req->rc, c->proto_version, "s?d",
> -								&ename, &ecode);
> -			if (err)
> -				goto out_err;
> +	if (!p9_is_proto_dotl(c)) {
> +		char *ename;
> +
> +		if (req->tc->pbuf_size) {
> +			/* Handle user buffers */
> +			size_t len = req->rc->size - req->rc->offset;
> +			if (req->tc->pubuf) {
> +				/* User Buffer */
> +				err = copy_from_user(
> +					&req->rc->sdata[req->rc->offset],
> +					req->tc->pubuf, len);
> +				if (err) {
> +					err = -EFAULT;
> +					return err;
> +				}

Will this handle error resulting from kernel_read ?. I guess we have a
kernel address there.


> +			} else {
> +				/* Kernel Buffer */
> +				memmove(&req->rc->sdata[req->rc->offset],
> +						req->tc->pkbuf, len);
> +			}
> +		}

-aneesh