[RFC PATCH 22/35] nfsd: split off the write decode code in to a seperate function

Frank van der Linden
2019-09-12T17:28:55Z

nfs4_decode_write has code to parse incoming XDR write data in to
a kvec head, and a list of pages.

Put this code in to a seperate function, so that it can be used
later by the xattr code, for setxattr. No functional change.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
fs/nfsd/nfs4xdr.c | 72 +++++++++++++++++++++++++++--------------------
1 file changed, 42 insertions(+), 30 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index f2090f7fed42..25cd597f7b4e 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -248,6 +248,44 @@ svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len)
return p;
}

+static __be32
+svcxdr_construct_vector(struct nfsd4_compoundargs *argp, struct kvec *head,
+ struct page ***pagelist, u32 buflen)
+{
+ int avail;
+ int len;
+ int pages;
+
+ /* Sorry .. no magic macros for this.. *
+ * READ_BUF(write->wr_buflen);
+ * SAVEMEM(write->wr_buf, write->wr_buflen);
+ */
+ avail = (char*)argp->end - (char*)argp->p;
+ if (avail + argp->pagelen < buflen) {
+ dprintk("NFSD: xdr error (%s:%d)\n",
+ __FILE__, __LINE__);
+ return nfserr_bad_xdr;
+ }
+ head->iov_base = argp->p;
+ head->iov_len = avail;
+ *pagelist = argp->pagelist;
+
+ len = XDR_QUADLEN(buflen) << 2;
+ if (len >= avail) {
+ len -= avail;
+
+ pages = len >> PAGE_SHIFT;
+ argp->pagelist += pages;
+ argp->pagelen -= pages * PAGE_SIZE;
+ len -= pages * PAGE_SIZE;
+
+ next_decode_page(argp);
+ }
+ argp->p += XDR_QUADLEN(len);
+
+ return 0;
+}
+
/**
* savemem - duplicate a chunk of memory for later processing
* @argp: NFSv4 compound argument structure to be freed with
@@ -1251,8 +1289,6 @@ nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify
static __be32
nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
{
- int avail;
- int len;
DECODE_HEAD;

status = nfsd4_decode_stateid(argp, &write->wr_stateid);
@@ -1265,34 +1301,10 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
goto xdr_error;
write->wr_buflen = be32_to_cpup(p++);

- /* Sorry .. no magic macros for this.. *
- * READ_BUF(write->wr_buflen);
- * SAVEMEM(write->wr_buf, write->wr_buflen);
- */
- avail = (char*)argp->end - (char*)argp->p;
- if (avail + argp->pagelen < write->wr_buflen) {
- dprintk("NFSD: xdr error (%s:%d)\n",
- __FILE__, __LINE__);
- goto xdr_error;
- }
- write->wr_head.iov_base = p;
- write->wr_head.iov_len = avail;
- write->wr_pagelist = argp->pagelist;
-
- len = XDR_QUADLEN(write->wr_buflen) << 2;
- if (len >= avail) {
- int pages;
-
- len -= avail;
-
- pages = len >> PAGE_SHIFT;
- argp->pagelist += pages;
- argp->pagelen -= pages * PAGE_SIZE;
- len -= pages * PAGE_SIZE;
-
- next_decode_page(argp);
- }
- argp->p += XDR_QUADLEN(len);
+ status = svcxdr_construct_vector(argp, &write->wr_head,
+ &write->wr_pagelist, write->wr_buflen);
+ if (status)
+ return status;

DECODE_TAIL;
}
--
2.17.2