Commit a9022746 authored by Stefan Metzmacher's avatar Stefan Metzmacher Committed by Steve French
Browse files

smb: server: simplify sibling_list handling in smb_direct_flush_send_list/send_done 



We have a list handling that is much easier to understand:

1. Before smb_direct_flush_send_list() is called all
   struct smbdirect_send_io messages are part of
   send_ctx->msg_list

2. Before smb_direct_flush_send_list() calls
   smb_direct_post_send() we remove the last
   element in send_ctx->msg_list and move all
   others into last->sibling_list. As only
   last has IB_SEND_SIGNALED and gets a completion
   vis send_done().

3. send_done() has an easy way to free all others
   in sendmsg->sibling_list (if there are any).
   And use list_for_each_entry_safe() instead of
   a complex custom logic.

This will help us to share send_done() in common
code soon, as it will work fine for the client too,
where last->sibling_list is currently always an empty list.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: default avatarStefan Metzmacher <metze@samba.org>
Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 8059c640

fs/smb/server/transport_rdma.c

+38 −22
Original line number Diff line number Diff line
@@ -523,6 +523,12 @@ static void smb_direct_free_sendmsg(struct smbdirect_socket *sc, 
{

	int i;



	/*

	 * The list needs to be empty!

	 * The caller should take care of it.

	 */

	WARN_ON_ONCE(!list_empty(&msg->sibling_list));



	if (msg->num_sge > 0) {

		ib_dma_unmap_single(sc->ib.dev,

				    msg->sge[0].addr, msg->sge[0].length,
@@ -908,9 +914,8 @@ static void smb_direct_post_recv_credits(struct work_struct *work) 


static void send_done(struct ib_cq *cq, struct ib_wc *wc)

{

	struct smbdirect_send_io *sendmsg, *sibling;

	struct smbdirect_send_io *sendmsg, *sibling, *next;

	struct smbdirect_socket *sc;

	struct list_head *pos, *prev, *end;



	sendmsg = container_of(wc->wr_cqe, struct smbdirect_send_io, cqe);

	sc = sendmsg->socket;
@@ -919,27 +924,26 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc) 
		    ib_wc_status_msg(wc->status), wc->status,

		    wc->opcode);



	/*

	 * Free possible siblings and then the main send_io

	 */

	list_for_each_entry_safe(sibling, next, &sendmsg->sibling_list, sibling_list) {

		list_del_init(&sibling->sibling_list);

		smb_direct_free_sendmsg(sc, sibling);

	}

	/* Note this frees wc->wr_cqe, but not wc */

	smb_direct_free_sendmsg(sc, sendmsg);



	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {

		pr_err("Send error. status='%s (%d)', opcode=%d\n",

		       ib_wc_status_msg(wc->status), wc->status,

		       wc->opcode);

		smb_direct_disconnect_rdma_connection(sc);

		return;

	}



	if (atomic_dec_and_test(&sc->send_io.pending.count))

		wake_up(&sc->send_io.pending.zero_wait_queue);



	/* iterate and free the list of messages in reverse. the list's head

	 * is invalid.

	 */

	for (pos = &sendmsg->sibling_list, prev = pos->prev, end = sendmsg->sibling_list.next;

	     prev != end; pos = prev, prev = prev->prev) {

		sibling = container_of(pos, struct smbdirect_send_io, sibling_list);

		smb_direct_free_sendmsg(sc, sibling);

	}



	sibling = container_of(pos, struct smbdirect_send_io, sibling_list);

	smb_direct_free_sendmsg(sc, sibling);

}



static int manage_credits_prior_sending(struct smbdirect_socket *sc)
@@ -1029,17 +1033,29 @@ static int smb_direct_flush_send_list(struct smbdirect_socket *sc, 
	last->wr.send_flags = IB_SEND_SIGNALED;

	last->wr.wr_cqe = &last->cqe;



	/*

	 * Remove last from send_ctx->msg_list

	 * and splice the rest of send_ctx->msg_list

	 * to last->sibling_list.

	 *

	 * send_ctx->msg_list is a valid empty list

	 * at the end.

	 */

	list_del_init(&last->sibling_list);

	list_splice_tail_init(&send_ctx->msg_list, &last->sibling_list);

	send_ctx->wr_cnt = 0;



	ret = smb_direct_post_send(sc, &first->wr);

	if (!ret) {

		smb_direct_send_ctx_init(send_ctx,

					 send_ctx->need_invalidate_rkey,

					 send_ctx->remote_key);

	} else {

		list_for_each_entry_safe(first, last, &send_ctx->msg_list,

					 sibling_list) {

			smb_direct_free_sendmsg(sc, first);

	if (ret) {

		struct smbdirect_send_io *sibling, *next;



		list_for_each_entry_safe(sibling, next, &last->sibling_list, sibling_list) {

			list_del_init(&sibling->sibling_list);

			smb_direct_free_sendmsg(sc, sibling);

		}

		smb_direct_free_sendmsg(sc, last);

	}



	return ret;

}