Re: [V9fs-developer] [PATCH 1/2] net/9p: embed fcall in req to round down buffer allocs
From: Greg Kurz
Date: Wed Aug 01 2018 - 10:31:42 EST
On Mon, 30 Jul 2018 11:34:22 +0200
Dominique Martinet <asmadeus@xxxxxxxxxxxxx> wrote:
> From: Dominique Martinet <dominique.martinet@xxxxxx>
>
> 'msize' is often a power of two, or at least page-aligned, so avoiding
> an overhead of two dozen bytes for each allocation will help the
> allocator do its work and reduce memory fragmentation.
>
> Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Signed-off-by: Dominique Martinet <dominique.martinet@xxxxxx>
> ---
> include/net/9p/client.h | 4 +-
> net/9p/client.c | 160 ++++++++++++++++++++--------------------
> net/9p/trans_fd.c | 12 +--
> net/9p/trans_rdma.c | 29 ++++----
> net/9p/trans_virtio.c | 18 ++---
> net/9p/trans_xen.c | 12 +--
> 6 files changed, 117 insertions(+), 118 deletions(-)
>
> diff --git a/include/net/9p/client.h b/include/net/9p/client.h
> index a4dc42c53d18..4b4ac1362ad5 100644
> --- a/include/net/9p/client.h
> +++ b/include/net/9p/client.h
> @@ -95,8 +95,8 @@ struct p9_req_t {
> int status;
> int t_err;
> wait_queue_head_t wq;
> - struct p9_fcall *tc;
> - struct p9_fcall *rc;
> + struct p9_fcall tc;
> + struct p9_fcall rc;
> void *aux;
> struct list_head req_list;
> };
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 88db45966740..ba99a94a12c9 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -231,15 +231,13 @@ static int parse_opts(char *opts, struct p9_client *clnt)
> return ret;
> }
>
> -static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
> +static int p9_fcall_alloc(struct p9_fcall *fc, int alloc_msize)
> {
> - struct p9_fcall *fc;
> - fc = kmalloc(sizeof(struct p9_fcall) + alloc_msize, GFP_NOFS);
> - if (!fc)
> - return NULL;
> + fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
> + if (!fc->sdata)
> + return -ENOMEM;
> fc->capacity = alloc_msize;
> - fc->sdata = (char *) fc + sizeof(struct p9_fcall);
> - return fc;
> + return 0;
> }
>
> static struct kmem_cache *p9_req_cache;
> @@ -263,13 +261,13 @@ p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
> if (!req)
> return NULL;
>
> - req->tc = p9_fcall_alloc(alloc_msize);
> - req->rc = p9_fcall_alloc(alloc_msize);
> - if (!req->tc || !req->rc)
> + if (p9_fcall_alloc(&req->tc, alloc_msize))
> + goto free;
> + if (p9_fcall_alloc(&req->rc, alloc_msize))
> goto free;
Hmm... if the first allocation fails, we will kfree() req->rc.sdata.
Are we sure we won't have a stale pointer or uninitialized data in
there ?
And even if we don't with the current code base, this is fragile and
could be easily broken.
I think you should drop this hunk and rather rename p9_fcall_alloc() to
p9_fcall_alloc_sdata() instead, since this is what the function is
actually doing with this patch applied.
>
> - p9pdu_reset(req->tc);
> - p9pdu_reset(req->rc);
> + p9pdu_reset(&req->tc);
> + p9pdu_reset(&req->rc);
> req->status = REQ_STATUS_ALLOC;
> init_waitqueue_head(&req->wq);
> INIT_LIST_HEAD(&req->req_list);
> @@ -281,7 +279,7 @@ p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
> GFP_NOWAIT);
> else
> tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
> - req->tc->tag = tag;
> + req->tc.tag = tag;
> spin_unlock_irq(&c->lock);
> idr_preload_end();
> if (tag < 0)
> @@ -290,8 +288,8 @@ p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
> return req;
>
> free:
> - kfree(req->tc);
> - kfree(req->rc);
> + kfree(req->tc.sdata);
> + kfree(req->rc.sdata);
> kmem_cache_free(p9_req_cache, req);
> return ERR_PTR(-ENOMEM);
> }
> @@ -329,14 +327,14 @@ EXPORT_SYMBOL(p9_tag_lookup);
> static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
> {
> unsigned long flags;
> - u16 tag = r->tc->tag;
> + 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);
> - kfree(r->tc);
> - kfree(r->rc);
> + kfree(r->tc.sdata);
> + kfree(r->rc.sdata);
> kmem_cache_free(p9_req_cache, r);
> }
>
> @@ -368,7 +366,7 @@ static void p9_tag_cleanup(struct p9_client *c)
> */
> 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);
> + p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
>
> /*
> * This barrier is needed to make sure any change made to req before
> @@ -378,7 +376,7 @@ void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
> req->status = status;
>
> wake_up(&req->wq);
> - p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
> + p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
> }
> EXPORT_SYMBOL(p9_client_cb);
>
> @@ -449,18 +447,18 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
> int err;
> int ecode;
>
> - err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
> - if (req->rc->size >= c->msize) {
> + 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);
> + 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);
> + trace_9p_protocol_dump(c, &req->rc);
> if (err) {
> p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
> return err;
> @@ -470,7 +468,7 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
>
> if (!p9_is_proto_dotl(c)) {
> char *ename;
> - err = p9pdu_readf(req->rc, c->proto_version, "s?d",
> + err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
> &ename, &ecode);
> if (err)
> goto out_err;
> @@ -486,7 +484,7 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
> }
> kfree(ename);
> } else {
> - err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
> + err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
> err = -ecode;
>
> p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
> @@ -520,12 +518,12 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
> int8_t type;
> char *ename = NULL;
>
> - err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
> + 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);
> + trace_9p_protocol_dump(c, &req->rc);
> if (err) {
> p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
> return err;
> @@ -540,13 +538,13 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
> /* 7 = header size for RERROR; */
> int inline_len = in_hdrlen - 7;
>
> - len = req->rc->size - req->rc->offset;
> + 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];
> + 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,
> @@ -556,7 +554,7 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
> }
> }
> ename = NULL;
> - err = p9pdu_readf(req->rc, c->proto_version, "s?d",
> + err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
> &ename, &ecode);
> if (err)
> goto out_err;
> @@ -572,7 +570,7 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
> }
> kfree(ename);
> } else {
> - err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
> + err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
> err = -ecode;
>
> p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
> @@ -605,7 +603,7 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
> int16_t oldtag;
> int err;
>
> - err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
> + err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
> if (err)
> return err;
>
> @@ -649,12 +647,12 @@ static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
> return req;
>
> /* marshall the data */
> - p9pdu_prepare(req->tc, req->tc->tag, type);
> - err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
> + 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);
> + p9pdu_finalize(c, &req->tc);
> + trace_9p_client_req(c, type, req->tc.tag);
> return req;
> reterr:
> p9_free_req(c, req);
> @@ -739,7 +737,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
> goto reterr;
>
> err = p9_check_errors(c, req);
> - trace_9p_client_res(c, type, req->rc->tag, err);
> + trace_9p_client_res(c, type, req->rc.tag, err);
> if (!err)
> return req;
> reterr:
> @@ -821,7 +819,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
> goto reterr;
>
> err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
> - trace_9p_client_res(c, type, req->rc->tag, err);
> + trace_9p_client_res(c, type, req->rc.tag, err);
> if (!err)
> return req;
> reterr:
> @@ -904,10 +902,10 @@ static int p9_client_version(struct p9_client *c)
> if (IS_ERR(req))
> return PTR_ERR(req);
>
> - err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
> + 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);
> + trace_9p_protocol_dump(c, &req->rc);
> goto error;
> }
>
> @@ -1056,9 +1054,9 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> goto error;
> }
> @@ -1113,9 +1111,9 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> goto clunk_fid;
> }
> @@ -1180,9 +1178,9 @@ int p9_client_open(struct p9_fid *fid, int mode)
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto free_and_error;
> }
>
> @@ -1224,9 +1222,9 @@ int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto free_and_error;
> }
>
> @@ -1269,9 +1267,9 @@ int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto free_and_error;
> }
>
> @@ -1308,9 +1306,9 @@ int p9_client_symlink(struct p9_fid *dfid, const char *name,
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto free_and_error;
> }
>
> @@ -1506,10 +1504,10 @@ p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
> break;
> }
>
> - *err = p9pdu_readf(req->rc, clnt->proto_version,
> + *err = p9pdu_readf(&req->rc, clnt->proto_version,
> "D", &count, &dataptr);
> if (*err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> break;
> }
> @@ -1579,9 +1577,9 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
> break;
> }
>
> - *err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
> + *err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
> if (*err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> break;
> }
> @@ -1623,9 +1621,9 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> goto error;
> }
> @@ -1676,9 +1674,9 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> goto error;
> }
> @@ -1828,11 +1826,11 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
> - &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
> - &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
> + &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
> + &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> goto error;
> }
> @@ -1936,9 +1934,9 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
> err = PTR_ERR(req);
> goto error;
> }
> - err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> p9_free_req(clnt, req);
> goto clunk_fid;
> }
> @@ -2024,9 +2022,9 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
> goto error;
> }
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto free_and_error;
> }
> if (rsize < count) {
> @@ -2065,9 +2063,9 @@ int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
> if (IS_ERR(req))
> return PTR_ERR(req);
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto error;
> }
> p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
> @@ -2096,9 +2094,9 @@ int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
> if (IS_ERR(req))
> return PTR_ERR(req);
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto error;
> }
> p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
> @@ -2131,9 +2129,9 @@ int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
> if (IS_ERR(req))
> return PTR_ERR(req);
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto error;
> }
> p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
> @@ -2162,11 +2160,11 @@ int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
> if (IS_ERR(req))
> return PTR_ERR(req);
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
> - &glock->start, &glock->length, &glock->proc_id,
> - &glock->client_id);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
> + &glock->start, &glock->length, &glock->proc_id,
> + &glock->client_id);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto error;
> }
> p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
> @@ -2192,9 +2190,9 @@ int p9_client_readlink(struct p9_fid *fid, char **target)
> if (IS_ERR(req))
> return PTR_ERR(req);
>
> - err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
> + err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
> if (err) {
> - trace_9p_protocol_dump(clnt, req->rc);
> + trace_9p_protocol_dump(clnt, &req->rc);
> goto error;
> }
> p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
> diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
> index e2ef3c782c53..20f46f13fe83 100644
> --- a/net/9p/trans_fd.c
> +++ b/net/9p/trans_fd.c
> @@ -354,7 +354,7 @@ static void p9_read_work(struct work_struct *work)
> goto error;
> }
>
> - if (m->req->rc == NULL) {
> + if (m->req->rc.sdata == NULL) {
> p9_debug(P9_DEBUG_ERROR,
> "No recv fcall for tag %d (req %p), disconnecting!\n",
> m->rc.tag, m->req);
> @@ -362,7 +362,7 @@ static void p9_read_work(struct work_struct *work)
> err = -EIO;
> goto error;
> }
> - m->rc.sdata = (char *)m->req->rc + sizeof(struct p9_fcall);
> + m->rc.sdata = m->req->rc.sdata;
> memcpy(m->rc.sdata, m->tmp_buf, m->rc.capacity);
> m->rc.capacity = m->rc.size;
> }
> @@ -372,7 +372,7 @@ static void p9_read_work(struct work_struct *work)
> */
> if ((m->req) && (m->rc.offset == m->rc.capacity)) {
> p9_debug(P9_DEBUG_TRANS, "got new packet\n");
> - m->req->rc->size = m->rc.offset;
> + m->req->rc.size = m->rc.offset;
> spin_lock(&m->client->lock);
> if (m->req->status != REQ_STATUS_ERROR)
> status = REQ_STATUS_RCVD;
> @@ -469,8 +469,8 @@ static void p9_write_work(struct work_struct *work)
> p9_debug(P9_DEBUG_TRANS, "move req %p\n", req);
> list_move_tail(&req->req_list, &m->req_list);
>
> - m->wbuf = req->tc->sdata;
> - m->wsize = req->tc->size;
> + m->wbuf = req->tc.sdata;
> + m->wsize = req->tc.size;
> m->wpos = 0;
> spin_unlock(&m->client->lock);
> }
> @@ -663,7 +663,7 @@ static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
> struct p9_conn *m = &ts->conn;
>
> p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n",
> - m, current, req->tc, req->tc->id);
> + m, current, &req->tc, req->tc.id);
> if (m->err < 0)
> return m->err;
>
> diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
> index 2ab4574183c9..c5cac97df7f7 100644
> --- a/net/9p/trans_rdma.c
> +++ b/net/9p/trans_rdma.c
> @@ -122,7 +122,7 @@ struct p9_rdma_context {
> dma_addr_t busa;
> union {
> struct p9_req_t *req;
> - struct p9_fcall *rc;
> + struct p9_fcall rc;
> };
> };
>
> @@ -320,8 +320,8 @@ recv_done(struct ib_cq *cq, struct ib_wc *wc)
> if (wc->status != IB_WC_SUCCESS)
> goto err_out;
>
> - c->rc->size = wc->byte_len;
> - err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
> + c->rc.size = wc->byte_len;
> + err = p9_parse_header(&c->rc, NULL, NULL, &tag, 1);
> if (err)
> goto err_out;
>
> @@ -331,12 +331,13 @@ recv_done(struct ib_cq *cq, struct ib_wc *wc)
>
> /* Check that we have not yet received a reply for this request.
> */
> - if (unlikely(req->rc)) {
> + if (unlikely(req->rc.sdata)) {
> pr_err("Duplicate reply for request %d", tag);
> goto err_out;
> }
>
> - req->rc = c->rc;
> + req->rc.size = c->rc.size;
> + req->rc.sdata = c->rc.sdata;
> p9_client_cb(client, req, REQ_STATUS_RCVD);
>
> out:
> @@ -361,7 +362,7 @@ send_done(struct ib_cq *cq, struct ib_wc *wc)
> container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
>
> ib_dma_unmap_single(rdma->cm_id->device,
> - c->busa, c->req->tc->size,
> + c->busa, c->req->tc.size,
> DMA_TO_DEVICE);
> up(&rdma->sq_sem);
> kfree(c);
> @@ -401,7 +402,7 @@ post_recv(struct p9_client *client, struct p9_rdma_context *c)
> struct ib_sge sge;
>
> c->busa = ib_dma_map_single(rdma->cm_id->device,
> - c->rc->sdata, client->msize,
> + c->rc.sdata, client->msize,
> DMA_FROM_DEVICE);
> if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
> goto error;
> @@ -443,9 +444,9 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
> **/
> if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
> if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
> - /* Got one ! */
> - kfree(req->rc);
> - req->rc = NULL;
> + /* Got one! */
> + kfree(req->rc.sdata);
> + req->rc.sdata = NULL;
> goto dont_need_post_recv;
> } else {
> /* We raced and lost. */
> @@ -459,7 +460,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
> err = -ENOMEM;
> goto recv_error;
> }
> - rpl_context->rc = req->rc;
> + rpl_context->rc.sdata = req->rc.sdata;
>
> /*
> * Post a receive buffer for this request. We need to ensure
> @@ -479,7 +480,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
> goto recv_error;
> }
> /* remove posted receive buffer from request structure */
> - req->rc = NULL;
> + req->rc.sdata = NULL;
>
> dont_need_post_recv:
> /* Post the request */
> @@ -491,7 +492,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
> c->req = req;
>
> c->busa = ib_dma_map_single(rdma->cm_id->device,
> - c->req->tc->sdata, c->req->tc->size,
> + c->req->tc.sdata, c->req->tc.size,
> DMA_TO_DEVICE);
> if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
> err = -EIO;
> @@ -501,7 +502,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
> c->cqe.done = send_done;
>
> sge.addr = c->busa;
> - sge.length = c->req->tc->size;
> + sge.length = c->req->tc.size;
> sge.lkey = rdma->pd->local_dma_lkey;
>
> wr.next = NULL;
> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
> index 6265d1d62749..80dd34d8a6af 100644
> --- a/net/9p/trans_virtio.c
> +++ b/net/9p/trans_virtio.c
> @@ -157,7 +157,7 @@ static void req_done(struct virtqueue *vq)
> }
>
> if (len) {
> - req->rc->size = len;
> + req->rc.size = len;
> p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
> }
> }
> @@ -274,12 +274,12 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
> out_sgs = in_sgs = 0;
> /* Handle out VirtIO ring buffers */
> out = pack_sg_list(chan->sg, 0,
> - VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
> + VIRTQUEUE_NUM, req->tc.sdata, req->tc.size);
> if (out)
> sgs[out_sgs++] = chan->sg;
>
> in = pack_sg_list(chan->sg, out,
> - VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity);
> + VIRTQUEUE_NUM, req->rc.sdata, req->rc.capacity);
> if (in)
> sgs[out_sgs + in_sgs++] = chan->sg + out;
>
> @@ -417,15 +417,15 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
> out_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
> if (n != outlen) {
> __le32 v = cpu_to_le32(n);
> - memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4);
> + memcpy(&req->tc.sdata[req->tc.size - 4], &v, 4);
> outlen = n;
> }
> /* The size field of the message must include the length of the
> * header and the length of the data. We didn't actually know
> * the length of the data until this point so add it in now.
> */
> - sz = cpu_to_le32(req->tc->size + outlen);
> - memcpy(&req->tc->sdata[0], &sz, sizeof(sz));
> + sz = cpu_to_le32(req->tc.size + outlen);
> + memcpy(&req->tc.sdata[0], &sz, sizeof(sz));
> } else if (uidata) {
> int n = p9_get_mapped_pages(chan, &in_pages, uidata,
> inlen, &offs, &need_drop);
> @@ -434,7 +434,7 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
> in_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
> if (n != inlen) {
> __le32 v = cpu_to_le32(n);
> - memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4);
> + memcpy(&req->tc.sdata[req->tc.size - 4], &v, 4);
> inlen = n;
> }
> }
> @@ -446,7 +446,7 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
>
> /* out data */
> out = pack_sg_list(chan->sg, 0,
> - VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
> + VIRTQUEUE_NUM, req->tc.sdata, req->tc.size);
>
> if (out)
> sgs[out_sgs++] = chan->sg;
> @@ -465,7 +465,7 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
> * alloced memory and payload onto the user buffer.
> */
> in = pack_sg_list(chan->sg, out,
> - VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len);
> + VIRTQUEUE_NUM, req->rc.sdata, in_hdr_len);
> if (in)
> sgs[out_sgs + in_sgs++] = chan->sg + out;
>
> diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
> index c2d54ac76bfd..1a5b38892eb4 100644
> --- a/net/9p/trans_xen.c
> +++ b/net/9p/trans_xen.c
> @@ -141,7 +141,7 @@ static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
> struct xen_9pfs_front_priv *priv = NULL;
> RING_IDX cons, prod, masked_cons, masked_prod;
> unsigned long flags;
> - u32 size = p9_req->tc->size;
> + u32 size = p9_req->tc.size;
> struct xen_9pfs_dataring *ring;
> int num;
>
> @@ -154,7 +154,7 @@ static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
> if (!priv || priv->client != client)
> return -EINVAL;
>
> - num = p9_req->tc->tag % priv->num_rings;
> + num = p9_req->tc.tag % priv->num_rings;
> ring = &priv->rings[num];
>
> again:
> @@ -176,7 +176,7 @@ static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
> masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
> masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
>
> - xen_9pfs_write_packet(ring->data.out, p9_req->tc->sdata, size,
> + xen_9pfs_write_packet(ring->data.out, p9_req->tc.sdata, size,
> &masked_prod, masked_cons, XEN_9PFS_RING_SIZE);
>
> p9_req->status = REQ_STATUS_SENT;
> @@ -229,12 +229,12 @@ static void p9_xen_response(struct work_struct *work)
> continue;
> }
>
> - memcpy(req->rc, &h, sizeof(h));
> - req->rc->offset = 0;
> + memcpy(&req->rc, &h, sizeof(h));
> + req->rc.offset = 0;
>
> masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
> /* Then, read the whole packet (including the header) */
> - xen_9pfs_read_packet(req->rc->sdata, ring->data.in, h.size,
> + xen_9pfs_read_packet(req->rc.sdata, ring->data.in, h.size,
> masked_prod, &masked_cons,
> XEN_9PFS_RING_SIZE);
>