9p: embed fcall in req to round down buffer allocs

'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.

Link: http://lkml.kernel.org/r/1533825236-22896-1-git-send-email-asmadeus@codewreck.orgSuggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reviewed-by: Greg Kurz <groug@kaod.org>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>

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;
 };
@@ -230,6 +230,7 @@ int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
 				kgid_t gid, struct p9_qid *);
 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
+void p9_fcall_fini(struct p9_fcall *fc);
 struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
 

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) {
 			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;
 

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! */
+			p9_fcall_fini(&req->rc);
+			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;

net/9p/trans_virtio.c

@@ -155,7 +155,7 @@ 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);
 		}
 	}
@@ -273,12 +273,12 @@ 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;
 
@@ -416,15 +416,15 @@ 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);
@@ -433,7 +433,7 @@ 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;
 		}
 	}
@@ -445,7 +445,7 @@ 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;
@@ -464,7 +464,7 @@ 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;
 

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);