Commit aa563d7b authored by David Howells's avatar David Howells
Browse files

iov_iter: Separate type from direction and use accessor functions 



In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.

Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements.  This makes it easier to add further
iterator types.  Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.

Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself.  Only the direction is required.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 00e23707

drivers/block/drbd/drbd_main.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1856,7 +1856,7 @@ int drbd_send(struct drbd_connection *connection, struct socket *sock, 




	/* THINK  if (signal_pending) return ... ? */

	/* THINK  if (signal_pending) return ... ? */





	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, &iov, 1, size);

	iov_iter_kvec(&msg.msg_iter, WRITE, &iov, 1, size);





	if (sock == connection->data.socket) {

	if (sock == connection->data.socket) {

		rcu_read_lock();

		rcu_read_lock();

drivers/block/drbd/drbd_receiver.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -516,7 +516,7 @@ static int drbd_recv_short(struct socket *sock, void *buf, size_t size, int flag 
	struct msghdr msg = {

	struct msghdr msg = {

		.msg_flags = (flags ? flags : MSG_WAITALL | MSG_NOSIGNAL)

		.msg_flags = (flags ? flags : MSG_WAITALL | MSG_NOSIGNAL)

	};

	};

	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &iov, 1, size);

	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, size);

	return sock_recvmsg(sock, &msg, msg.msg_flags);

	return sock_recvmsg(sock, &msg, msg.msg_flags);

}

}

drivers/block/loop.c

+4 −5
Original line number Original line Diff line number Diff line
@@ -268,7 +268,7 @@ static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) 
	struct iov_iter i;

	struct iov_iter i;

	ssize_t bw;

	ssize_t bw;





	iov_iter_bvec(&i, ITER_BVEC | WRITE, bvec, 1, bvec->bv_len);

	iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len);





	file_start_write(file);

	file_start_write(file);

	bw = vfs_iter_write(file, &i, ppos, 0);

	bw = vfs_iter_write(file, &i, ppos, 0);
@@ -346,7 +346,7 @@ static int lo_read_simple(struct loop_device *lo, struct request *rq, 
	ssize_t len;

	ssize_t len;





	rq_for_each_segment(bvec, rq, iter) {

	rq_for_each_segment(bvec, rq, iter) {

		iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);

		iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len);

		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);

		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);

		if (len < 0)

		if (len < 0)

			return len;

			return len;
@@ -387,7 +387,7 @@ static int lo_read_transfer(struct loop_device *lo, struct request *rq, 
		b.bv_offset = 0;

		b.bv_offset = 0;

		b.bv_len = bvec.bv_len;

		b.bv_len = bvec.bv_len;





		iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);

		iov_iter_bvec(&i, READ, &b, 1, b.bv_len);

		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);

		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);

		if (len < 0) {

		if (len < 0) {

			ret = len;

			ret = len;
@@ -554,8 +554,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, 
	}

	}

	atomic_set(&cmd->ref, 2);

	atomic_set(&cmd->ref, 2);





	iov_iter_bvec(&iter, ITER_BVEC | rw, bvec,

	iov_iter_bvec(&iter, rw, bvec, segments, blk_rq_bytes(rq));

		      segments, blk_rq_bytes(rq));

	iter.iov_offset = offset;

	iter.iov_offset = offset;





	cmd->iocb.ki_pos = pos;

	cmd->iocb.ki_pos = pos;

drivers/block/nbd.c

+5 −7
Original line number Original line Diff line number Diff line
@@ -473,7 +473,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 
	u32 nbd_cmd_flags = 0;

	u32 nbd_cmd_flags = 0;

	int sent = nsock->sent, skip = 0;

	int sent = nsock->sent, skip = 0;





	iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));

	iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));





	switch (req_op(req)) {

	switch (req_op(req)) {

	case REQ_OP_DISCARD:

	case REQ_OP_DISCARD:
@@ -564,8 +564,7 @@ send_pages: 




			dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",

			dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",

				req, bvec.bv_len);

				req, bvec.bv_len);

			iov_iter_bvec(&from, ITER_BVEC | WRITE,

			iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);

				      &bvec, 1, bvec.bv_len);

			if (skip) {

			if (skip) {

				if (skip >= iov_iter_count(&from)) {

				if (skip >= iov_iter_count(&from)) {

					skip -= iov_iter_count(&from);

					skip -= iov_iter_count(&from);
@@ -624,7 +623,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) 
	int ret = 0;

	int ret = 0;





	reply.magic = 0;

	reply.magic = 0;

	iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));

	iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));

	result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);

	result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);

	if (result <= 0) {

	if (result <= 0) {

		if (!nbd_disconnected(config))

		if (!nbd_disconnected(config))
@@ -678,8 +677,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) 
		struct bio_vec bvec;

		struct bio_vec bvec;





		rq_for_each_segment(bvec, req, iter) {

		rq_for_each_segment(bvec, req, iter) {

			iov_iter_bvec(&to, ITER_BVEC | READ,

			iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);

				      &bvec, 1, bvec.bv_len);

			result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);

			result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);

			if (result <= 0) {

			if (result <= 0) {

				dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",

				dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
@@ -1073,7 +1071,7 @@ static void send_disconnects(struct nbd_device *nbd) 
	for (i = 0; i < config->num_connections; i++) {

	for (i = 0; i < config->num_connections; i++) {

		struct nbd_sock *nsock = config->socks[i];

		struct nbd_sock *nsock = config->socks[i];





		iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));

		iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));

		mutex_lock(&nsock->tx_lock);

		mutex_lock(&nsock->tx_lock);

		ret = sock_xmit(nbd, i, 1, &from, 0, NULL);

		ret = sock_xmit(nbd, i, 1, &from, 0, NULL);

		if (ret <= 0)

		if (ret <= 0)

drivers/fsi/fsi-sbefifo.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -638,7 +638,7 @@ static void sbefifo_collect_async_ffdc(struct sbefifo *sbefifo) 
	}

	}

        ffdc_iov.iov_base = ffdc;

        ffdc_iov.iov_base = ffdc;

	ffdc_iov.iov_len = SBEFIFO_MAX_FFDC_SIZE;

	ffdc_iov.iov_len = SBEFIFO_MAX_FFDC_SIZE;

        iov_iter_kvec(&ffdc_iter, WRITE | ITER_KVEC, &ffdc_iov, 1, SBEFIFO_MAX_FFDC_SIZE);

        iov_iter_kvec(&ffdc_iter, WRITE, &ffdc_iov, 1, SBEFIFO_MAX_FFDC_SIZE);

	cmd[0] = cpu_to_be32(2);

	cmd[0] = cpu_to_be32(2);

	cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_SBE_FFDC);

	cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_SBE_FFDC);

	rc = sbefifo_do_command(sbefifo, cmd, 2, &ffdc_iter);

	rc = sbefifo_do_command(sbefifo, cmd, 2, &ffdc_iter);
@@ -735,7 +735,7 @@ int sbefifo_submit(struct device *dev, const __be32 *command, size_t cmd_len, 
	rbytes = (*resp_len) * sizeof(__be32);

	rbytes = (*resp_len) * sizeof(__be32);

	resp_iov.iov_base = response;

	resp_iov.iov_base = response;

	resp_iov.iov_len = rbytes;

	resp_iov.iov_len = rbytes;

        iov_iter_kvec(&resp_iter, WRITE | ITER_KVEC, &resp_iov, 1, rbytes);

        iov_iter_kvec(&resp_iter, WRITE, &resp_iov, 1, rbytes);





	/* Perform the command */

	/* Perform the command */

	mutex_lock(&sbefifo->lock);

	mutex_lock(&sbefifo->lock);

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