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Commit e5374399 authored by Eugene Crosser's avatar Eugene Crosser Committed by David S. Miller
Browse files

af_iucv: use paged SKBs for big outbound messages 



When an outbound message is bigger than a page, allocate and fill
a paged SKB, and subsequently use IUCV send primitive with IPBUFLST
flag. This relaxes the pressure to allocate big contiguous kernel
buffers.

Signed-off-by: default avatarEugene Crosser <Eugene.Crosser@ru.ibm.com>
Signed-off-by: default avatarUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 818d49ad

net/iucv/af_iucv.c

+77 −47
Original line number Diff line number Diff line
@@ -1033,6 +1033,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
{

	struct sock *sk = sock->sk;

	struct iucv_sock *iucv = iucv_sk(sk);

	size_t headroom, linear;

	struct sk_buff *skb;

	struct iucv_message txmsg = {0};

	struct cmsghdr *cmsg;
@@ -1110,20 +1111,31 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
	 * this is fine for SOCK_SEQPACKET (unless we want to support

	 * segmented records using the MSG_EOR flag), but

	 * for SOCK_STREAM we might want to improve it in future */

	if (iucv->transport == AF_IUCV_TRANS_HIPER)

		skb = sock_alloc_send_skb(sk,

			len + sizeof(struct af_iucv_trans_hdr) + ETH_HLEN,

			noblock, &err);

	else

		skb = sock_alloc_send_skb(sk, len, noblock, &err);

	headroom = (iucv->transport == AF_IUCV_TRANS_HIPER)

		   ? sizeof(struct af_iucv_trans_hdr) + ETH_HLEN : 0;

	if (headroom + len < PAGE_SIZE) {

		linear = len;

	} else {

		/* In nonlinear "classic" iucv skb,

		 * reserve space for iucv_array

		 */

		if (iucv->transport != AF_IUCV_TRANS_HIPER)

			headroom += sizeof(struct iucv_array) *

				    (MAX_SKB_FRAGS + 1);

		linear = PAGE_SIZE - headroom;

	}

	skb = sock_alloc_send_pskb(sk, headroom + linear, len - linear,

				   noblock, &err, 0);

	if (!skb)

		goto out;

	if (iucv->transport == AF_IUCV_TRANS_HIPER)

		skb_reserve(skb, sizeof(struct af_iucv_trans_hdr) + ETH_HLEN);

	if (memcpy_from_msg(skb_put(skb, len), msg, len)) {

		err = -EFAULT;

	if (headroom)

		skb_reserve(skb, headroom);

	skb_put(skb, linear);

	skb->len = len;

	skb->data_len = len - linear;

	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);

	if (err)

		goto fail;

	}



	/* wait if outstanding messages for iucv path has reached */

	timeo = sock_sndtimeo(sk, noblock);
@@ -1148,49 +1160,67 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
			atomic_dec(&iucv->msg_sent);

			goto fail;

		}

		goto release;

	}

	} else { /* Classic VM IUCV transport */

		skb_queue_tail(&iucv->send_skb_q, skb);



	if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags)

	      && skb->len <= 7) {

		if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) &&

		    skb->len <= 7) {

			err = iucv_send_iprm(iucv->path, &txmsg, skb);



		/* on success: there is no message_complete callback

		 * for an IPRMDATA msg; remove skb from send queue */

			/* on success: there is no message_complete callback */

			/* for an IPRMDATA msg; remove skb from send queue   */

			if (err == 0) {

				skb_unlink(skb, &iucv->send_skb_q);

				kfree_skb(skb);

			}



		/* this error should never happen since the

		 * IUCV_IPRMDATA path flag is set... sever path */

			/* this error should never happen since the	*/

			/* IUCV_IPRMDATA path flag is set... sever path */

			if (err == 0x15) {

				pr_iucv->path_sever(iucv->path, NULL);

				skb_unlink(skb, &iucv->send_skb_q);

				err = -EPIPE;

				goto fail;

			}

	} else

		err = pr_iucv->message_send(iucv->path, &txmsg, 0, 0,

					(void *) skb->data, skb->len);

		} else if (skb_is_nonlinear(skb)) {

			struct iucv_array *iba = (struct iucv_array *)skb->head;

			int i;



			/* skip iucv_array lying in the headroom */

			iba[0].address = (u32)(addr_t)skb->data;

			iba[0].length = (u32)skb_headlen(skb);

			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];



				iba[i + 1].address =

					(u32)(addr_t)skb_frag_address(frag);

				iba[i + 1].length = (u32)skb_frag_size(frag);

			}

			err = pr_iucv->message_send(iucv->path, &txmsg,

						    IUCV_IPBUFLST, 0,

						    (void *)iba, skb->len);

		} else { /* non-IPRM Linear skb */

			err = pr_iucv->message_send(iucv->path, &txmsg,

					0, 0, (void *)skb->data, skb->len);

		}

		if (err) {

			if (err == 3) {

				user_id[8] = 0;

				memcpy(user_id, iucv->dst_user_id, 8);

				appl_id[8] = 0;

				memcpy(appl_id, iucv->dst_name, 8);

			pr_err("Application %s on z/VM guest %s"

				" exceeds message limit\n",

				pr_err(

		"Application %s on z/VM guest %s exceeds message limit\n",

					appl_id, user_id);

				err = -EAGAIN;

		} else

			} else {

				err = -EPIPE;

			}

			skb_unlink(skb, &iucv->send_skb_q);

			goto fail;

		}

	}



release:

	release_sock(sk);

	return len;