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Commit e7015fb1 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Simplify socket reading in demultiplex thread 



Move reading to separate function and remove csocket variable.

Also change semantic in a little: goto incomplete_rcv only when
we get -EAGAIN (or a familiar error) while reading rfc1002 header.
In this case we don't check for echo timeout when we don't get whole
header at once, as it was before.

Reviewed-and-Tested-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarPavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 3d9c2472

fs/cifs/connect.c

+71 −83
Original line number Diff line number Diff line
@@ -358,6 +358,64 @@ allocate_buffers(char **bigbuf, char **smallbuf, unsigned int size, 
	return true;

}



static int

read_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg,

		 struct kvec *iov, unsigned int to_read,

		 unsigned int *ptotal_read, bool is_header_read)

{

	int length, rc = 0;

	unsigned int total_read;

	char *buf = iov->iov_base;



	for (total_read = 0; total_read < to_read; total_read += length) {

		length = kernel_recvmsg(server->ssocket, smb_msg, iov, 1,

					to_read - total_read, 0);

		if (server->tcpStatus == CifsExiting) {

			/* then will exit */

			rc = 2;

			break;

		} else if (server->tcpStatus == CifsNeedReconnect) {

			cifs_reconnect(server);

			/* Reconnect wakes up rspns q */

			/* Now we will reread sock */

			rc = 1;

			break;

		} else if (length == -ERESTARTSYS ||

			   length == -EAGAIN ||

			   length == -EINTR) {

			/*

			 * Minimum sleep to prevent looping, allowing socket

			 * to clear and app threads to set tcpStatus

			 * CifsNeedReconnect if server hung.

			 */

			usleep_range(1000, 2000);

			length = 0;

			if (!is_header_read)

				continue;

			/* Special handling for header read */

			if (total_read) {

				iov->iov_base = (to_read - total_read) +

						buf;

				iov->iov_len = to_read - total_read;

				smb_msg->msg_control = NULL;

				smb_msg->msg_controllen = 0;

				rc = 3;

			} else

				rc = 1;

			break;

		} else if (length <= 0) {

			cERROR(1, "Received no data, expecting %d",

			       to_read - total_read);

			cifs_reconnect(server);

			rc = 1;

			break;

		}

	}



	*ptotal_read = total_read;

	return rc;

}



static int

cifs_demultiplex_thread(void *p)

{
@@ -368,14 +426,13 @@ cifs_demultiplex_thread(void *p) 
	struct smb_hdr *smb_buffer = NULL;

	struct msghdr smb_msg;

	struct kvec iov;

	struct socket *csocket = server->ssocket;

	struct list_head *tmp, *tmp2;

	struct task_struct *task_to_wake = NULL;

	struct mid_q_entry *mid_entry;

	char temp;

	bool isLargeBuf = false;

	bool isMultiRsp;

	int reconnect;

	int rc;



	current->flags |= PF_MEMALLOC;

	cFYI(1, "Demultiplex PID: %d", task_pid_nr(current));
@@ -412,51 +469,18 @@ incomplete_rcv: 
				  "Reconnecting...", server->hostname,

				  (echo_retries * SMB_ECHO_INTERVAL / HZ));

			cifs_reconnect(server);

			csocket = server->ssocket;

			wake_up(&server->response_q);

			continue;

		}



		length =

		    kernel_recvmsg(csocket, &smb_msg,

				&iov, 1, pdu_length, 0 /* BB other flags? */);



		if (server->tcpStatus == CifsExiting) {

			break;

		} else if (server->tcpStatus == CifsNeedReconnect) {

			cFYI(1, "Reconnect after server stopped responding");

			cifs_reconnect(server);

			cFYI(1, "call to reconnect done");

			csocket = server->ssocket;

			continue;

		} else if (length == -ERESTARTSYS ||

			   length == -EAGAIN ||

			   length == -EINTR) {

			msleep(1); /* minimum sleep to prevent looping

				allowing socket to clear and app threads to set

				tcpStatus CifsNeedReconnect if server hung */

			if (pdu_length < 4) {

				iov.iov_base = (4 - pdu_length) + buf;

				iov.iov_len = pdu_length;

				smb_msg.msg_control = NULL;

				smb_msg.msg_controllen = 0;

		rc = read_from_socket(server, &smb_msg, &iov, pdu_length,

				      &total_read, true /* header read */);

		if (rc == 3)

			goto incomplete_rcv;

			} else

				continue;

		} else if (length <= 0) {

			cFYI(1, "Reconnect after unexpected peek error %d",

				length);

			cifs_reconnect(server);

			csocket = server->ssocket;

			wake_up(&server->response_q);

		else if (rc == 2)

			break;

		else if (rc == 1)

			continue;

		} else if (length < pdu_length) {

			cFYI(1, "requested %d bytes but only got %d bytes",

				  pdu_length, length);

			pdu_length -= length;

			msleep(1);

			goto incomplete_rcv;

		}



		/* The right amount was read from socket - 4 bytes */

		/* so we can now interpret the length field */
@@ -493,14 +517,12 @@ incomplete_rcv: 
			cifs_set_port((struct sockaddr *)

					&server->dstaddr, CIFS_PORT);

			cifs_reconnect(server);

			csocket = server->ssocket;

			wake_up(&server->response_q);

			continue;

		} else if (temp != (char) 0) {

			cERROR(1, "Unknown RFC 1002 frame");

			cifs_dump_mem(" Received Data: ", buf, length);

			cifs_reconnect(server);

			csocket = server->ssocket;

			continue;

		}
@@ -510,59 +532,25 @@ incomplete_rcv: 
			cERROR(1, "Invalid size SMB length %d pdu_length %d",

					length, pdu_length+4);

			cifs_reconnect(server);

			csocket = server->ssocket;

			wake_up(&server->response_q);

			continue;

		}



		/* else length ok */

		reconnect = 0;



		if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {

			isLargeBuf = true;

			memcpy(bigbuf, smallbuf, 4);

			smb_buffer = (struct smb_hdr *)bigbuf;

			buf = bigbuf;

		}

		length = 0;



		iov.iov_base = 4 + buf;

		iov.iov_len = pdu_length;

		for (total_read = 0; total_read < pdu_length;

		     total_read += length) {

			length = kernel_recvmsg(csocket, &smb_msg, &iov, 1,

						pdu_length - total_read, 0);

			if (server->tcpStatus == CifsExiting) {

				/* then will exit */

				reconnect = 2;

				break;

			} else if (server->tcpStatus == CifsNeedReconnect) {

				cifs_reconnect(server);

				csocket = server->ssocket;

				/* Reconnect wakes up rspns q */

				/* Now we will reread sock */

				reconnect = 1;

		rc = read_from_socket(server, &smb_msg, &iov, pdu_length,

				      &total_read, false);

		if (rc == 2)

			break;

			} else if (length == -ERESTARTSYS ||

				   length == -EAGAIN ||

				   length == -EINTR) {

				msleep(1); /* minimum sleep to prevent looping,

					      allowing socket to clear and app

					      threads to set tcpStatus

					      CifsNeedReconnect if server hung*/

				length = 0;

				continue;

			} else if (length <= 0) {

				cERROR(1, "Received no data, expecting %d",

					      pdu_length - total_read);

				cifs_reconnect(server);

				csocket = server->ssocket;

				reconnect = 1;

				break;

			}

		}

		if (reconnect == 2)

			break;

		else if (reconnect == 1)

		else if (rc == 1)

			continue;



		total_read += 4; /* account for rfc1002 hdr */
@@ -705,7 +693,7 @@ multi_t2_fnd: 
	msleep(125);



	if (server->ssocket) {

		sock_release(csocket);

		sock_release(server->ssocket);

		server->ssocket = NULL;

	}

	/* buffer usually freed in free_mid - need to free it here on exit */