From 47c1f956e7f212aec0eec174c3fb5801eae5d5bc Mon Sep 17 00:00:00 2001

From: Chris Leech <cleech@redhat.com>

Date: Thu, 24 Jan 2019 18:16:47 -0800

Subject: [PATCH 1/1] fcoemon: link buffer resize fix

---

 fcoemon.c | 54 ++++++++++++++++++------------------------------------

 1 file changed, 18 insertions(+), 36 deletions(-)

diff --git a/fcoemon.c b/fcoemon.c

index bf73a0d4c89e..ff8a8b869ba4 100644

--- a/fcoemon.c

+++ b/fcoemon.c

@@ -328,7 +328,6 @@ static int fcm_link_socket;

 static int fcm_link_seq;

 static void fcm_link_recv(void *);

 static void fcm_link_getlink(void);

-static int fcm_link_buf_check(size_t);

 static void clear_dcbd_info(struct fcm_netif *ff);

 static int fcoe_vid_from_ifname(const char *ifname);

@@ -354,8 +353,7 @@ char progname[20];

  * large enough to fit and expand it if we ever do a read that almost fills it.

  */

 static char *fcm_link_buf;

-static size_t fcm_link_buf_size = 4096;	/* initial size */

-static const size_t fcm_link_buf_fuzz = 300;	/* "almost full" remainder */

+static size_t fcm_link_buf_size = 8192;	/* initial size */

 /*

  * A value must be surrounded by quates, e.g. "x".

@@ -1856,8 +1854,22 @@ static void fcm_link_recv(UNUSED void *arg)

 	size_t plen;

 	size_t rlen;

+	/* check to make sure our receive buffer is large enough,

+	 * or scale it up as needed */

+	rc = recv(fcm_link_socket, NULL, 0, MSG_PEEK | MSG_TRUNC);

+	if (rc > fcm_link_buf_size) {

+		FCM_LOG_DBG("resizing link buf to %d bytes\n", rc);

+		void *resize = realloc(fcm_link_buf, rc);

+		if (resize) {

+			fcm_link_buf = resize;

+			fcm_link_buf_size = rc;

+		} else {

+			FCM_LOG_ERR(errno, "Failed to allocate link buffer");

+		}

+	}

+

 	buf = fcm_link_buf;

-	rc = read(fcm_link_socket, buf, fcm_link_buf_size);

+	rc = recv(fcm_link_socket, buf, fcm_link_buf_size, 0);

 	if (rc <= 0) {

 		if (rc < 0)

 			FCM_LOG_ERR(errno, "Error reading from "

@@ -1866,11 +1878,6 @@ static void fcm_link_recv(UNUSED void *arg)

 		return;

 	}

-	if (fcm_link_buf_check(rc)) {

-		fcm_link_getlink();

-		return;

-	}

-

 	hp = (struct nlmsghdr *)buf;

 	rlen = rc;

 	for (hp = (struct nlmsghdr *)buf; NLMSG_OK(hp, rlen);

@@ -1935,34 +1942,9 @@ static void fcm_link_getlink(void)

 	msg.nl.nlmsg_pid = getpid();

 	msg.ifi.ifi_family = AF_UNSPEC;

 	msg.ifi.ifi_type = ARPHRD_ETHER;

-	rc = write(fcm_link_socket, &msg, sizeof(msg));

+	rc = send(fcm_link_socket, &msg, sizeof(msg), 0);

 	if (rc < 0)

-		FCM_LOG_ERR(errno, "write error");

-}

-

-/*

- * Check for whether buffer needs to grow based on amount read.

- * Free's the old buffer so don't use that after this returns non-zero.

- */

-static int fcm_link_buf_check(size_t read_len)

-{

-	char *buf;

-	size_t len = read_len;

-

-	if (len > fcm_link_buf_size - fcm_link_buf_fuzz) {

-		len = fcm_link_buf_size;

-		len = len + len / 2;	/* grow by 50% */

-		buf = malloc(len);

-		if (buf != NULL) {

-			free(fcm_link_buf);

-			fcm_link_buf = buf;

-			fcm_link_buf_size = len;

-			return 1;

-		} else {

-			FCM_LOG_ERR(errno, "failed to allocate link buffer");

-		}

-	}

-	return 0;

+		FCM_LOG_ERR(errno, "send error");

 }

 static void fcm_fcoe_init(void)

-- 

2.17.2