[PATCH v1 22/42] NFSD: Update the NFSv2 READ argument decoder to use struct xdr_stream

Chuck Lever
2021-01-05T15:32:37Z

The code that sets up rq_vec is refactored so that it is now
adjacent to the nfsd_read() call site where it is used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfsproc.c | 32 ++++++++++++++++++--------------
fs/nfsd/nfsxdr.c | 36 ++++++++++++------------------------
fs/nfsd/xdr.h | 1 -
3 files changed, 30 insertions(+), 39 deletions(-)

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index b9bc162a5c77..814762793f9c 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -171,32 +171,36 @@ nfsd_proc_read(struct svc_rqst *rqstp)
{
struct nfsd_readargs *argp = rqstp->rq_argp;
struct nfsd_readres *resp = rqstp->rq_resp;
+ unsigned int len;
u32 eof;
+ int v;

dprintk("nfsd: READ %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->count, argp->offset);

+ argp->count = min_t(u32, argp->count, NFSSVC_MAXBLKSIZE_V2);
+
+ v = 0;
+ len = argp->count;
+ while (len > 0) {
+ struct page *page = *(rqstp->rq_next_page++);
+
+ rqstp->rq_vec[v].iov_base = page_address(page);
+ rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
+ len -= rqstp->rq_vec[v].iov_len;
+ v++;
+ }
+
/* Obtain buffer pointer for payload. 19 is 1 word for
* status, 17 words for fattr, and 1 word for the byte count.
*/
-
- if (NFSSVC_MAXBLKSIZE_V2 < argp->count) {
- char buf[RPC_MAX_ADDRBUFLEN];
- printk(KERN_NOTICE
- "oversized read request from %s (%d bytes)\n",
- svc_print_addr(rqstp, buf, sizeof(buf)),
- argp->count);
- argp->count = NFSSVC_MAXBLKSIZE_V2;
- }
svc_reserve_auth(rqstp, (19<<2) + argp->count + 4);

resp->count = argp->count;
- resp->status = nfsd_read(rqstp, fh_copy(&resp->fh, &argp->fh),
- argp->offset,
- rqstp->rq_vec, argp->vlen,
- &resp->count,
- &eof);
+ fh_copy(&resp->fh, &argp->fh);
+ resp->status = nfsd_read(rqstp, &resp->fh, argp->offset,
+ rqstp->rq_vec, v, &resp->count, &eof);
if (resp->status == nfs_ok)
resp->status = fh_getattr(&resp->fh, &resp->stat);
else if (resp->status == nfserr_jukebox)
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index f3189e1be20f..1eacaa2c13a9 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -246,33 +246,21 @@ nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
int
nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
{
+ struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd_readargs *args = rqstp->rq_argp;
- unsigned int len;
- int v;
- p = decode_fh(p, &args->fh);
- if (!p)
- return 0;
+ u32 totalcount;

- args->offset = ntohl(*p++);
- len = args->count = ntohl(*p++);
- p++; /* totalcount - unused */
-
- len = min_t(unsigned int, len, NFSSVC_MAXBLKSIZE_V2);
+ if (!svcxdr_decode_fhandle(xdr, &args->fh))
+ return 0;
+ if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
+ return 0;
+ if (xdr_stream_decode_u32(xdr, &args->count) < 0)
+ return 0;
+ /* totalcount is ignored */
+ if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
+ return 0;

- /* set up somewhere to store response.
- * We take pages, put them on reslist and include in iovec
- */
- v=0;
- while (len > 0) {
- struct page *p = *(rqstp->rq_next_page++);
-
- rqstp->rq_vec[v].iov_base = page_address(p);
- rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
- len -= rqstp->rq_vec[v].iov_len;
- v++;
- }
- args->vlen = v;
- return xdr_argsize_check(rqstp, p);
+ return 1;
}

int
diff --git a/fs/nfsd/xdr.h b/fs/nfsd/xdr.h
index 84256a6a1ba1..d2ffda96975d 100644
--- a/fs/nfsd/xdr.h
+++ b/fs/nfsd/xdr.h
@@ -27,7 +27,6 @@ struct nfsd_readargs {
struct svc_fh fh;
__u32 offset;
__u32 count;
- int vlen;
};

struct nfsd_writeargs {