This is a note to let you know that I've just added the patch titled
SUNRPC: Prepare for xdr_stream-style decoding on the server-side
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sunrpc-prepare-for-xdr_stream-style-decoding-on-the-.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ba564cda1b99d035764257f9c3fc615b81efb780
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Thu Nov 5 11:19:42 2020 -0500
SUNRPC: Prepare for xdr_stream-style decoding on the server-side
[ Upstream commit 5191955d6fc65e6d4efe8f4f10a6028298f57281 ]
A "permanent" struct xdr_stream is allocated in struct svc_rqst so
that it is usable by all server-side decoders. A per-rqst scratch
buffer is also allocated to handle decoding XDR data items that
cross page boundaries.
To demonstrate how it will be used, add the first call site for the
new svcxdr_init_decode() API.
As an additional part of the overall conversion, add symbolic
constants for successful and failed XDR operations. Returning "0" is
overloaded. Sometimes it means something failed, but sometimes it
means success. To make it more clear when XDR decoding functions
succeed or fail, introduce symbolic constants.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Stable-dep-of: 401bc1f90874 ("NFSD: Protect against send buffer overflow in NFSv2 READ")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 9323e30a7eaf..ad6fedf37a40 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -1019,6 +1019,8 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
* (necessary in the NFSv4.0 compound case)
*/
rqstp->rq_cachetype = proc->pc_cachetype;
+
+ svcxdr_init_decode(rqstp);
if (!proc->pc_decode(rqstp, argv->iov_base))
goto out_decode_err;
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 386628b36bc7..6ce2e12589cb 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -247,6 +247,8 @@ struct svc_rqst {
size_t rq_xprt_hlen; /* xprt header len */
struct xdr_buf rq_arg;
+ struct xdr_stream rq_arg_stream;
+ struct page *rq_scratch_page;
struct xdr_buf rq_res;
struct page *rq_pages[RPCSVC_MAXPAGES + 1];
struct page * *rq_respages; /* points into rq_pages */
@@ -557,4 +559,18 @@ static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
svc_reserve(rqstp, space + rqstp->rq_auth_slack);
}
+/**
+ * svcxdr_init_decode - Prepare an xdr_stream for svc Call decoding
+ * @rqstp: controlling server RPC transaction context
+ *
+ */
+static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
+{
+ struct xdr_stream *xdr = &rqstp->rq_arg_stream;
+ struct kvec *argv = rqstp->rq_arg.head;
+
+ xdr_init_decode(xdr, &rqstp->rq_arg, argv->iov_base, NULL);
+ xdr_set_scratch_page(xdr, rqstp->rq_scratch_page);
+}
+
#endif /* SUNRPC_SVC_H */
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index d38788cd9433..bb55f124b62e 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -614,6 +614,10 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
rqstp->rq_server = serv;
rqstp->rq_pool = pool;
+ rqstp->rq_scratch_page = alloc_pages_node(node, GFP_KERNEL, 0);
+ if (!rqstp->rq_scratch_page)
+ goto out_enomem;
+
rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
if (!rqstp->rq_argp)
goto out_enomem;
@@ -842,6 +846,7 @@ void
svc_rqst_free(struct svc_rqst *rqstp)
{
svc_release_buffer(rqstp);
+ put_page(rqstp->rq_scratch_page);
kfree(rqstp->rq_resp);
kfree(rqstp->rq_argp);
kfree(rqstp->rq_auth_data);
