linux/fs/nfs/mount_clnt.c
Chuck Lever 2bea90d43a SUNRPC: RPC buffer size estimates are too large
The RPC buffer size estimation logic in net/sunrpc/clnt.c always
significantly overestimates the requirements for the buffer size.
A little instrumentation demonstrated that in fact rpc_malloc was never
allocating the buffer from the mempool, but almost always called kmalloc.

To compute the size of the RPC buffer more precisely, split p_bufsiz into
two fields; one for the argument size, and one for the result size.

Then, compute the sum of the exact call and reply header sizes, and split
the RPC buffer precisely between the two.  That should keep almost all RPC
buffers within the 2KiB buffer mempool limit.

And, we can finally be rid of RPC_SLACK_SPACE!

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-04-30 22:17:10 -07:00

191 lines
4.1 KiB
C

/*
* linux/fs/nfs/mount_clnt.c
*
* MOUNT client to support NFSroot.
*
* Copyright (C) 1997, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/sched.h>
#include <linux/nfs_fs.h>
#ifdef RPC_DEBUG
# define NFSDBG_FACILITY NFSDBG_ROOT
#endif
/*
#define MOUNT_PROGRAM 100005
#define MOUNT_VERSION 1
#define MOUNT_MNT 1
#define MOUNT_UMNT 3
*/
static struct rpc_clnt * mnt_create(char *, struct sockaddr_in *,
int, int);
static struct rpc_program mnt_program;
struct mnt_fhstatus {
unsigned int status;
struct nfs_fh * fh;
};
/*
* Obtain an NFS file handle for the given host and path
*/
int
nfsroot_mount(struct sockaddr_in *addr, char *path, struct nfs_fh *fh,
int version, int protocol)
{
struct rpc_clnt *mnt_clnt;
struct mnt_fhstatus result = {
.fh = fh
};
struct rpc_message msg = {
.rpc_argp = path,
.rpc_resp = &result,
};
char hostname[32];
int status;
dprintk("NFS: nfs_mount(%08x:%s)\n",
(unsigned)ntohl(addr->sin_addr.s_addr), path);
sprintf(hostname, "%u.%u.%u.%u", NIPQUAD(addr->sin_addr.s_addr));
mnt_clnt = mnt_create(hostname, addr, version, protocol);
if (IS_ERR(mnt_clnt))
return PTR_ERR(mnt_clnt);
if (version == NFS_MNT3_VERSION)
msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
else
msg.rpc_proc = &mnt_clnt->cl_procinfo[MNTPROC_MNT];
status = rpc_call_sync(mnt_clnt, &msg, 0);
return status < 0? status : (result.status? -EACCES : 0);
}
static struct rpc_clnt *
mnt_create(char *hostname, struct sockaddr_in *srvaddr, int version,
int protocol)
{
struct rpc_create_args args = {
.protocol = protocol,
.address = (struct sockaddr *)srvaddr,
.addrsize = sizeof(*srvaddr),
.servername = hostname,
.program = &mnt_program,
.version = version,
.authflavor = RPC_AUTH_UNIX,
.flags = (RPC_CLNT_CREATE_ONESHOT |
RPC_CLNT_CREATE_INTR),
};
return rpc_create(&args);
}
/*
* XDR encode/decode functions for MOUNT
*/
static int
xdr_encode_dirpath(struct rpc_rqst *req, __be32 *p, const char *path)
{
p = xdr_encode_string(p, path);
req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
return 0;
}
static int
xdr_decode_fhstatus(struct rpc_rqst *req, __be32 *p, struct mnt_fhstatus *res)
{
struct nfs_fh *fh = res->fh;
if ((res->status = ntohl(*p++)) == 0) {
fh->size = NFS2_FHSIZE;
memcpy(fh->data, p, NFS2_FHSIZE);
}
return 0;
}
static int
xdr_decode_fhstatus3(struct rpc_rqst *req, __be32 *p, struct mnt_fhstatus *res)
{
struct nfs_fh *fh = res->fh;
if ((res->status = ntohl(*p++)) == 0) {
int size = ntohl(*p++);
if (size <= NFS3_FHSIZE) {
fh->size = size;
memcpy(fh->data, p, size);
} else
res->status = -EBADHANDLE;
}
return 0;
}
#define MNT_dirpath_sz (1 + 256)
#define MNT_fhstatus_sz (1 + 8)
#define MNT_fhstatus3_sz (1 + 16)
static struct rpc_procinfo mnt_procedures[] = {
[MNTPROC_MNT] = {
.p_proc = MNTPROC_MNT,
.p_encode = (kxdrproc_t) xdr_encode_dirpath,
.p_decode = (kxdrproc_t) xdr_decode_fhstatus,
.p_arglen = MNT_dirpath_sz,
.p_replen = MNT_fhstatus_sz,
.p_statidx = MNTPROC_MNT,
.p_name = "MOUNT",
},
};
static struct rpc_procinfo mnt3_procedures[] = {
[MOUNTPROC3_MNT] = {
.p_proc = MOUNTPROC3_MNT,
.p_encode = (kxdrproc_t) xdr_encode_dirpath,
.p_decode = (kxdrproc_t) xdr_decode_fhstatus3,
.p_arglen = MNT_dirpath_sz,
.p_replen = MNT_fhstatus3_sz,
.p_statidx = MOUNTPROC3_MNT,
.p_name = "MOUNT",
},
};
static struct rpc_version mnt_version1 = {
.number = 1,
.nrprocs = 2,
.procs = mnt_procedures
};
static struct rpc_version mnt_version3 = {
.number = 3,
.nrprocs = 2,
.procs = mnt3_procedures
};
static struct rpc_version * mnt_version[] = {
NULL,
&mnt_version1,
NULL,
&mnt_version3,
};
static struct rpc_stat mnt_stats;
static struct rpc_program mnt_program = {
.name = "mount",
.number = NFS_MNT_PROGRAM,
.nrvers = ARRAY_SIZE(mnt_version),
.version = mnt_version,
.stats = &mnt_stats,
};