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client.c
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client.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* net/9p/clnt.c
*
* 9P Client
*
* Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "protocol.h"
#define CREATE_TRACE_POINTS
#include <trace/events/9p.h>
/*
* Client Option Parsing (code inspired by NFS code)
* - a little lazy - parse all client options
*/
enum {
Opt_msize,
Opt_trans,
Opt_legacy,
Opt_version,
Opt_err,
};
static const match_table_t tokens = {
{Opt_msize, "msize=%u"},
{Opt_legacy, "noextend"},
{Opt_trans, "trans=%s"},
{Opt_version, "version=%s"},
{Opt_err, NULL},
};
inline int p9_is_proto_dotl(struct p9_client *clnt)
{
return clnt->proto_version == p9_proto_2000L;
}
EXPORT_SYMBOL(p9_is_proto_dotl);
inline int p9_is_proto_dotu(struct p9_client *clnt)
{
return clnt->proto_version == p9_proto_2000u;
}
EXPORT_SYMBOL(p9_is_proto_dotu);
int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
{
if (clnt->msize != 8192)
seq_printf(m, ",msize=%u", clnt->msize);
seq_printf(m, ",trans=%s", clnt->trans_mod->name);
switch (clnt->proto_version) {
case p9_proto_legacy:
seq_puts(m, ",noextend");
break;
case p9_proto_2000u:
seq_puts(m, ",version=9p2000.u");
break;
case p9_proto_2000L:
/* Default */
break;
}
if (clnt->trans_mod->show_options)
return clnt->trans_mod->show_options(m, clnt);
return 0;
}
EXPORT_SYMBOL(p9_show_client_options);
/*
* Some error codes are taken directly from the server replies,
* make sure they are valid.
*/
static int safe_errno(int err)
{
if ((err > 0) || (err < -MAX_ERRNO)) {
p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
return -EPROTO;
}
return err;
}
/* Interpret mount option for protocol version */
static int get_protocol_version(char *s)
{
int version = -EINVAL;
if (!strcmp(s, "9p2000")) {
version = p9_proto_legacy;
p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
} else if (!strcmp(s, "9p2000.u")) {
version = p9_proto_2000u;
p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
} else if (!strcmp(s, "9p2000.L")) {
version = p9_proto_2000L;
p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
} else
pr_info("Unknown protocol version %s\n", s);
return version;
}
/**
* parse_options - parse mount options into client structure
* @opts: options string passed from mount
* @clnt: existing v9fs client information
*
* Return 0 upon success, -ERRNO upon failure
*/
static int parse_opts(char *opts, struct p9_client *clnt)
{
char *options, *tmp_options;
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
char *s;
int ret = 0;
clnt->proto_version = p9_proto_2000L;
clnt->msize = 8192;
if (!opts)
return 0;
tmp_options = kstrdup(opts, GFP_KERNEL);
if (!tmp_options) {
p9_debug(P9_DEBUG_ERROR,
"failed to allocate copy of option string\n");
return -ENOMEM;
}
options = tmp_options;
while ((p = strsep(&options, ",")) != NULL) {
int token, r;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_msize:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
continue;
}
if (option < 4096) {
p9_debug(P9_DEBUG_ERROR,
"msize should be at least 4k\n");
ret = -EINVAL;
continue;
}
clnt->msize = option;
break;
case Opt_trans:
s = match_strdup(&args[0]);
if (!s) {
ret = -ENOMEM;
p9_debug(P9_DEBUG_ERROR,
"problem allocating copy of trans arg\n");
goto free_and_return;
}
v9fs_put_trans(clnt->trans_mod);
clnt->trans_mod = v9fs_get_trans_by_name(s);
if (clnt->trans_mod == NULL) {
pr_info("Could not find request transport: %s\n",
s);
ret = -EINVAL;
}
kfree(s);
break;
case Opt_legacy:
clnt->proto_version = p9_proto_legacy;
break;
case Opt_version:
s = match_strdup(&args[0]);
if (!s) {
ret = -ENOMEM;
p9_debug(P9_DEBUG_ERROR,
"problem allocating copy of version arg\n");
goto free_and_return;
}
r = get_protocol_version(s);
if (r < 0)
ret = r;
else
clnt->proto_version = r;
kfree(s);
break;
default:
continue;
}
}
free_and_return:
if (ret)
v9fs_put_trans(clnt->trans_mod);
kfree(tmp_options);
return ret;
}
static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
int alloc_msize)
{
if (likely(c->fcall_cache) && alloc_msize == c->msize) {
fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
fc->cache = c->fcall_cache;
} else {
fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
fc->cache = NULL;
}
if (!fc->sdata)
return -ENOMEM;
fc->capacity = alloc_msize;
return 0;
}
void p9_fcall_fini(struct p9_fcall *fc)
{
/* sdata can be NULL for interrupted requests in trans_rdma,
* and kmem_cache_free does not do NULL-check for us
*/
if (unlikely(!fc->sdata))
return;
if (fc->cache)
kmem_cache_free(fc->cache, fc->sdata);
else
kfree(fc->sdata);
}
EXPORT_SYMBOL(p9_fcall_fini);
static struct kmem_cache *p9_req_cache;
/**
* p9_req_alloc - Allocate a new request.
* @c: Client session.
* @type: Transaction type.
* @max_size: Maximum packet size for this request.
*
* Context: Process context.
* Return: Pointer to new request.
*/
static struct p9_req_t *
p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
{
struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
int alloc_msize = min(c->msize, max_size);
int tag;
if (!req)
return ERR_PTR(-ENOMEM);
if (p9_fcall_init(c, &req->tc, alloc_msize))
goto free_req;
if (p9_fcall_init(c, &req->rc, alloc_msize))
goto free;
p9pdu_reset(&req->tc);
p9pdu_reset(&req->rc);
req->t_err = 0;
req->status = REQ_STATUS_ALLOC;
init_waitqueue_head(&req->wq);
INIT_LIST_HEAD(&req->req_list);
idr_preload(GFP_NOFS);
spin_lock_irq(&c->lock);
if (type == P9_TVERSION)
tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
GFP_NOWAIT);
else
tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
req->tc.tag = tag;
spin_unlock_irq(&c->lock);
idr_preload_end();
if (tag < 0)
goto free;
/* Init ref to two because in the general case there is one ref
* that is put asynchronously by a writer thread, one ref
* temporarily given by p9_tag_lookup and put by p9_client_cb
* in the recv thread, and one ref put by p9_tag_remove in the
* main thread. The only exception is virtio that does not use
* p9_tag_lookup but does not have a writer thread either
* (the write happens synchronously in the request/zc_request
* callback), so p9_client_cb eats the second ref there
* as the pointer is duplicated directly by virtqueue_add_sgs()
*/
refcount_set(&req->refcount.refcount, 2);
return req;
free:
p9_fcall_fini(&req->tc);
p9_fcall_fini(&req->rc);
free_req:
kmem_cache_free(p9_req_cache, req);
return ERR_PTR(-ENOMEM);
}
/**
* p9_tag_lookup - Look up a request by tag.
* @c: Client session.
* @tag: Transaction ID.
*
* Context: Any context.
* Return: A request, or %NULL if there is no request with that tag.
*/
struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
{
struct p9_req_t *req;
rcu_read_lock();
again:
req = idr_find(&c->reqs, tag);
if (req) {
/* We have to be careful with the req found under rcu_read_lock
* Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
* ref again without corrupting other data, then check again
* that the tag matches once we have the ref
*/
if (!p9_req_try_get(req))
goto again;
if (req->tc.tag != tag) {
p9_req_put(req);
goto again;
}
}
rcu_read_unlock();
return req;
}
EXPORT_SYMBOL(p9_tag_lookup);
/**
* p9_tag_remove - Remove a tag.
* @c: Client session.
* @r: Request of reference.
*
* Context: Any context.
*/
static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
{
unsigned long flags;
u16 tag = r->tc.tag;
p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
spin_lock_irqsave(&c->lock, flags);
idr_remove(&c->reqs, tag);
spin_unlock_irqrestore(&c->lock, flags);
return p9_req_put(r);
}
static void p9_req_free(struct kref *ref)
{
struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
p9_fcall_fini(&r->tc);
p9_fcall_fini(&r->rc);
kmem_cache_free(p9_req_cache, r);
}
int p9_req_put(struct p9_req_t *r)
{
return kref_put(&r->refcount, p9_req_free);
}
EXPORT_SYMBOL(p9_req_put);
/**
* p9_tag_cleanup - cleans up tags structure and reclaims resources
* @c: v9fs client struct
*
* This frees resources associated with the tags structure
*
*/
static void p9_tag_cleanup(struct p9_client *c)
{
struct p9_req_t *req;
int id;
rcu_read_lock();
idr_for_each_entry(&c->reqs, req, id) {
pr_info("Tag %d still in use\n", id);
if (p9_tag_remove(c, req) == 0)
pr_warn("Packet with tag %d has still references",
req->tc.tag);
}
rcu_read_unlock();
}
/**
* p9_client_cb - call back from transport to client
* c: client state
* req: request received
*
*/
void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
{
p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
/*
* This barrier is needed to make sure any change made to req before
* the status change is visible to another thread
*/
smp_wmb();
req->status = status;
wake_up(&req->wq);
p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
p9_req_put(req);
}
EXPORT_SYMBOL(p9_client_cb);
/**
* p9_parse_header - parse header arguments out of a packet
* @pdu: packet to parse
* @size: size of packet
* @type: type of request
* @tag: tag of packet
* @rewind: set if we need to rewind offset afterwards
*/
int
p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
int rewind)
{
int8_t r_type;
int16_t r_tag;
int32_t r_size;
int offset = pdu->offset;
int err;
pdu->offset = 0;
err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
if (err)
goto rewind_and_exit;
if (type)
*type = r_type;
if (tag)
*tag = r_tag;
if (size)
*size = r_size;
if (pdu->size != r_size || r_size < 7) {
err = -EINVAL;
goto rewind_and_exit;
}
pdu->id = r_type;
pdu->tag = r_tag;
p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
pdu->size, pdu->id, pdu->tag);
rewind_and_exit:
if (rewind)
pdu->offset = offset;
return err;
}
EXPORT_SYMBOL(p9_parse_header);
/**
* p9_check_errors - check 9p packet for error return and process it
* @c: current client instance
* @req: request to parse and check for error conditions
*
* returns error code if one is discovered, otherwise returns 0
*
* this will have to be more complicated if we have multiple
* error packet types
*/
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 (req->rc.size >= c->msize) {
p9_debug(P9_DEBUG_ERROR,
"requested packet size too big: %d\n",
req->rc.size);
return -EIO;
}
/*
* dump the response from server
* This should be after check errors which poplulate pdu_fcall.
*/
trace_9p_protocol_dump(c, &req->rc);
if (err) {
p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
return err;
}
if (type != P9_RERROR && type != P9_RLERROR)
return 0;
if (!p9_is_proto_dotl(c)) {
char *ename;
err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
&ename, &ecode);
if (err)
goto out_err;
if (p9_is_proto_dotu(c) && ecode < 512)
err = -ecode;
if (!err) {
err = p9_errstr2errno(ename, strlen(ename));
p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
-ecode, ename);
}
kfree(ename);
} else {
err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
err = -ecode;
p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
}
return err;
out_err:
p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
return err;
}
/**
* p9_check_zc_errors - check 9p packet for error return and process it
* @c: current client instance
* @req: request to parse and check for error conditions
* @in_hdrlen: Size of response protocol buffer.
*
* returns error code if one is discovered, otherwise returns 0
*
* this will have to be more complicated if we have multiple
* error packet types
*/
static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
struct iov_iter *uidata, int in_hdrlen)
{
int err;
int ecode;
int8_t type;
char *ename = NULL;
err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
/*
* dump the response from server
* This should be after parse_header which poplulate pdu_fcall.
*/
trace_9p_protocol_dump(c, &req->rc);
if (err) {
p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
return err;
}
if (type != P9_RERROR && type != P9_RLERROR)
return 0;
if (!p9_is_proto_dotl(c)) {
/* Error is reported in string format */
int len;
/* 7 = header size for RERROR; */
int inline_len = in_hdrlen - 7;
len = req->rc.size - req->rc.offset;
if (len > (P9_ZC_HDR_SZ - 7)) {
err = -EFAULT;
goto out_err;
}
ename = &req->rc.sdata[req->rc.offset];
if (len > inline_len) {
/* We have error in external buffer */
if (!copy_from_iter_full(ename + inline_len,
len - inline_len, uidata)) {
err = -EFAULT;
goto out_err;
}
}
ename = NULL;
err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
&ename, &ecode);
if (err)
goto out_err;
if (p9_is_proto_dotu(c) && ecode < 512)
err = -ecode;
if (!err) {
err = p9_errstr2errno(ename, strlen(ename));
p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
-ecode, ename);
}
kfree(ename);
} else {
err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
err = -ecode;
p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
}
return err;
out_err:
p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
return err;
}
static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
/**
* p9_client_flush - flush (cancel) a request
* @c: client state
* @oldreq: request to cancel
*
* This sents a flush for a particular request and links
* the flush request to the original request. The current
* code only supports a single flush request although the protocol
* allows for multiple flush requests to be sent for a single request.
*
*/
static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
{
struct p9_req_t *req;
int16_t oldtag;
int err;
err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
if (err)
return err;
p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
if (IS_ERR(req))
return PTR_ERR(req);
/*
* if we haven't received a response for oldreq,
* remove it from the list
*/
if (oldreq->status == REQ_STATUS_SENT) {
if (c->trans_mod->cancelled)
c->trans_mod->cancelled(c, oldreq);
}
p9_tag_remove(c, req);
return 0;
}
static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
int8_t type, int req_size,
const char *fmt, va_list ap)
{
int err;
struct p9_req_t *req;
p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
/* we allow for any status other than disconnected */
if (c->status == Disconnected)
return ERR_PTR(-EIO);
/* if status is begin_disconnected we allow only clunk request */
if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
return ERR_PTR(-EIO);
req = p9_tag_alloc(c, type, req_size);
if (IS_ERR(req))
return req;
/* marshall the data */
p9pdu_prepare(&req->tc, req->tc.tag, type);
err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
if (err)
goto reterr;
p9pdu_finalize(c, &req->tc);
trace_9p_client_req(c, type, req->tc.tag);
return req;
reterr:
p9_tag_remove(c, req);
/* We have to put also the 2nd reference as it won't be used */
p9_req_put(req);
return ERR_PTR(err);
}
/**
* p9_client_rpc - issue a request and wait for a response
* @c: client session
* @type: type of request
* @fmt: protocol format string (see protocol.c)
*
* Returns request structure (which client must free using p9_tag_remove)
*/
static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
{
va_list ap;
int sigpending, err;
unsigned long flags;
struct p9_req_t *req;
va_start(ap, fmt);
req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
va_end(ap);
if (IS_ERR(req))
return req;
if (signal_pending(current)) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
} else
sigpending = 0;
err = c->trans_mod->request(c, req);
if (err < 0) {
/* write won't happen */
p9_req_put(req);
if (err != -ERESTARTSYS && err != -EFAULT)
c->status = Disconnected;
goto recalc_sigpending;
}
again:
/* Wait for the response */
err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
/*
* Make sure our req is coherent with regard to updates in other
* threads - echoes to wmb() in the callback
*/
smp_rmb();
if ((err == -ERESTARTSYS) && (c->status == Connected)
&& (type == P9_TFLUSH)) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
goto again;
}
if (req->status == REQ_STATUS_ERROR) {
p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
err = req->t_err;
}
if ((err == -ERESTARTSYS) && (c->status == Connected)) {
p9_debug(P9_DEBUG_MUX, "flushing\n");
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
if (c->trans_mod->cancel(c, req))
p9_client_flush(c, req);
/* if we received the response anyway, don't signal error */
if (req->status == REQ_STATUS_RCVD)
err = 0;
}
recalc_sigpending:
if (sigpending) {
spin_lock_irqsave(¤t->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
}
if (err < 0)
goto reterr;
err = p9_check_errors(c, req);
trace_9p_client_res(c, type, req->rc.tag, err);
if (!err)
return req;
reterr:
p9_tag_remove(c, req);
return ERR_PTR(safe_errno(err));
}
/**
* p9_client_zc_rpc - issue a request and wait for a response
* @c: client session
* @type: type of request
* @uidata: destination for zero copy read
* @uodata: source for zero copy write
* @inlen: read buffer size
* @olen: write buffer size
* @hdrlen: reader header size, This is the size of response protocol data
* @fmt: protocol format string (see protocol.c)
*
* Returns request structure (which client must free using p9_tag_remove)
*/
static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
struct iov_iter *uidata,
struct iov_iter *uodata,
int inlen, int olen, int in_hdrlen,
const char *fmt, ...)
{
va_list ap;
int sigpending, err;
unsigned long flags;
struct p9_req_t *req;
va_start(ap, fmt);
/*
* We allocate a inline protocol data of only 4k bytes.
* The actual content is passed in zero-copy fashion.
*/
req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
va_end(ap);
if (IS_ERR(req))
return req;
if (signal_pending(current)) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
} else
sigpending = 0;
err = c->trans_mod->zc_request(c, req, uidata, uodata,
inlen, olen, in_hdrlen);
if (err < 0) {
if (err == -EIO)
c->status = Disconnected;
if (err != -ERESTARTSYS)
goto recalc_sigpending;
}
if (req->status == REQ_STATUS_ERROR) {
p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
err = req->t_err;
}
if ((err == -ERESTARTSYS) && (c->status == Connected)) {
p9_debug(P9_DEBUG_MUX, "flushing\n");
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
if (c->trans_mod->cancel(c, req))
p9_client_flush(c, req);
/* if we received the response anyway, don't signal error */
if (req->status == REQ_STATUS_RCVD)
err = 0;
}
recalc_sigpending:
if (sigpending) {
spin_lock_irqsave(¤t->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
}
if (err < 0)
goto reterr;
err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
trace_9p_client_res(c, type, req->rc.tag, err);
if (!err)
return req;
reterr:
p9_tag_remove(c, req);
return ERR_PTR(safe_errno(err));
}
static struct p9_fid *p9_fid_create(struct p9_client *clnt)
{
int ret;
struct p9_fid *fid;
p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
if (!fid)
return NULL;
memset(&fid->qid, 0, sizeof(struct p9_qid));
fid->mode = -1;
fid->uid = current_fsuid();
fid->clnt = clnt;
fid->rdir = NULL;
fid->fid = 0;
idr_preload(GFP_KERNEL);
spin_lock_irq(&clnt->lock);
ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
GFP_NOWAIT);
spin_unlock_irq(&clnt->lock);
idr_preload_end();
if (!ret)
return fid;
kfree(fid);
return NULL;
}
static void p9_fid_destroy(struct p9_fid *fid)
{
struct p9_client *clnt;
unsigned long flags;
p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
clnt = fid->clnt;
spin_lock_irqsave(&clnt->lock, flags);
idr_remove(&clnt->fids, fid->fid);
spin_unlock_irqrestore(&clnt->lock, flags);
kfree(fid->rdir);
kfree(fid);
}
static int p9_client_version(struct p9_client *c)
{
int err = 0;
struct p9_req_t *req;
char *version = NULL;
int msize;
p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
c->msize, c->proto_version);
switch (c->proto_version) {
case p9_proto_2000L:
req = p9_client_rpc(c, P9_TVERSION, "ds",
c->msize, "9P2000.L");
break;
case p9_proto_2000u:
req = p9_client_rpc(c, P9_TVERSION, "ds",
c->msize, "9P2000.u");
break;
case p9_proto_legacy:
req = p9_client_rpc(c, P9_TVERSION, "ds",
c->msize, "9P2000");
break;
default:
return -EINVAL;
}
if (IS_ERR(req))
return PTR_ERR(req);
err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
if (err) {
p9_debug(P9_DEBUG_9P, "version error %d\n", err);
trace_9p_protocol_dump(c, &req->rc);
goto error;
}
p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
if (!strncmp(version, "9P2000.L", 8))
c->proto_version = p9_proto_2000L;
else if (!strncmp(version, "9P2000.u", 8))
c->proto_version = p9_proto_2000u;
else if (!strncmp(version, "9P2000", 6))
c->proto_version = p9_proto_legacy;
else {
p9_debug(P9_DEBUG_ERROR,
"server returned an unknown version: %s\n", version);
err = -EREMOTEIO;
goto error;
}
if (msize < 4096) {
p9_debug(P9_DEBUG_ERROR,
"server returned a msize < 4096: %d\n", msize);
err = -EREMOTEIO;
goto error;
}
if (msize < c->msize)
c->msize = msize;
error:
kfree(version);
p9_tag_remove(c, req);
return err;
}
struct p9_client *p9_client_create(const char *dev_name, char *options)