1 files changed, 135 insertions, 0 deletions
diff --git a/package/hotplug2/patches/120-throttling.patch b/package/hotplug2/patches/120-throttling.patch
new file mode 100644
index 0000000..8d67b0c
--- /dev/null
+++ b/package/hotplug2/patches/120-throttling.patch
@@ -0,0 +1,135 @@
+--- a/hotplug2.c
++++ b/hotplug2.c
+@@ -21,6 +21,7 @@
+ #include <sys/mman.h>
+ #include <linux/types.h>
+ #include <linux/netlink.h>
++#include <poll.h>
+ 
+ #include "mem_utils.h"
+ #include "filemap_utils.h"
+@@ -492,6 +493,11 @@
+ 	char *coldplug_command = NULL;
+ 	char *rules_file = HOTPLUG2_RULE_PATH;
+ 	sigset_t block_mask;
++	struct pollfd msg_poll;
++
++	struct hotplug2_event_t *backlog = NULL;
++	struct hotplug2_event_t *backlog_tail = NULL;
++	int n_backlog = 0;
+ 	
+ 	struct rules_t *rules = NULL;
+ 	struct filemap_t filemap;
+@@ -602,6 +608,8 @@
+ 	 * Open netlink socket to read the uevents
+ 	 */
+ 	netlink_socket = init_netlink_socket(NETLINK_BIND);
++	msg_poll.fd = netlink_socket;
++	msg_poll.events = POLLIN;
+ 	
+ 	if (netlink_socket == -1) {
+ 		ERROR("netlink init","Unable to open netlink socket.");
+@@ -642,20 +650,45 @@
+ 	 * Main loop reading uevents
+ 	 */
+ 	while (!terminate) {
+-		/*
+-		 * Read the uevent packet
+-		 */
+-		size = recv(netlink_socket, &buffer, sizeof(buffer), 0);
+-		recv_errno = errno;
++		if ((n_backlog > 0) && (child_c < max_child_c)) {
++			/* dequeue backlog message */
++			tmpevent = backlog;
++			backlog = backlog->next;
++			n_backlog--;
++			if (backlog_tail == tmpevent)
++				backlog_tail = NULL;
++		} else {
++			/*
++			 * Read the uevent packet
++			 */
++			if (n_backlog >= HOTPLUG2_MSG_BACKLOG) {
++				usleep(HOTPLUG2_THROTTLE_INTERVAL * 1000);
++				continue;
++			}
++
++			if ((n_backlog > 0) && (child_c >= max_child_c)) {
++				int fds;
++				msg_poll.revents = 0;
++				fds = poll(&msg_poll, 1, HOTPLUG2_THROTTLE_INTERVAL);
++				if (fds < 0) {
++					perror("POLL FAILED");
++					continue;
++				}
++				if (fds == 0)
++					continue;
++			}
++			size = recv(netlink_socket, &buffer, sizeof(buffer), 0);
++			recv_errno = errno;
+ 	
+-		/*
+-		 * Parse the event into an event structure
+-		 */
+-		tmpevent = get_hotplug2_event(buffer, size);
++			/*
++			 * Parse the event into an event structure
++			 */
++			tmpevent = get_hotplug2_event(buffer, size);
+ 		
+-		if (tmpevent == NULL) {
+-			ERROR("reading events", "Malformed event read (missing action prefix).");
+-			continue;
++			if (tmpevent == NULL) {
++				ERROR("reading events", "Malformed event read (missing action prefix).");
++				continue;
++			}
+ 		}
+ 		
+ 		/*
+@@ -706,13 +739,16 @@
+ 			 * Unless, of course, we've specified otherwise and no rules that match
+ 			 * need throttling.
+ 			 */
+-			if (!flags & FLAG_NOTHROTTLE) {
+-				/*
+-				 * Okay, throttle away!
+-				 */
+-				while (child_c >= max_child_c) {
+-					usleep(HOTPLUG2_THROTTLE_INTERVAL);
+-				}
++			if (!(flags & FLAG_NOTHROTTLE) && (child_c >= max_child_c)) {
++				/* log the packet and process it later */
++				if (backlog_tail)
++					backlog_tail->next = tmpevent;
++				else
++					backlog = tmpevent;
++				tmpevent->next = NULL;
++				backlog_tail = tmpevent;
++				n_backlog++;
++				continue;
+ 			}
+ 			
+ 			sigemptyset(&block_mask);
+--- a/hotplug2.h
++++ b/hotplug2.h
+@@ -45,9 +45,9 @@
+ #define DBG(action, fmt, arg...)
+ #endif
+ 
++#define HOTPLUG2_MSG_BACKLOG	64
+ #define UEVENT_BUFFER_SIZE		2048
+-#define HOTPLUG2_POLL_INTERVAL		20000
+-#define HOTPLUG2_THROTTLE_INTERVAL	10000
++#define HOTPLUG2_THROTTLE_INTERVAL	50
+ #define HOTPLUG2_RULE_PATH		"/etc/hotplug2.rules"
+ 
+ #define ACTION_ADD			0
+@@ -76,6 +76,7 @@
+ 	int env_vars_c;
+ 	char *plain;
+ 	int plain_s;
++	struct hotplug2_event_t *next;
+ };
+ 
+ struct options_t {