svn commit: r339190 - stable/10/lib/libusb

[Hans Petter Selasky]

Author: hselasky
Date: Fri Oct  5 07:50:44 2018
New Revision: 339190
URL: https://svnweb.freebsd.org/changeset/base/339190

Log:
  MFC r338993:
  When multiple threads are involved receiving completion events in LibUSB
  make sure there is always a master polling thread, by setting the "ctx_handler"
  field in the context. Else the reception of completion events can stop.
  This happens if event threads are created and destroyed during runtime.
  
  Found by:		Ludovic Rousseau <ludovic.rousseau+freebsd at gmail.com>
  PR:			231742
  Sponsored by:		Mellanox Technologies

Modified:
  stable/10/lib/libusb/libusb10_io.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/lib/libusb/libusb10_io.c
==============================================================================
--- stable/10/lib/libusb/libusb10_io.c	Fri Oct  5 07:49:01 2018	(r339189)
+++ stable/10/lib/libusb/libusb10_io.c	Fri Oct  5 07:50:44 2018	(r339190)
@@ -310,6 +310,9 @@ libusb_wait_for_event(libusb_context *ctx, struct time
 	if (tv == NULL) {
 		pthread_cond_wait(&ctx->ctx_cond,
 		    &ctx->ctx_lock);
+		/* try to grab polling of actual events, if any */
+		if (ctx->ctx_handler == NO_THREAD)
+			ctx->ctx_handler = pthread_self();
 		return (0);
 	}
 	err = clock_gettime(CLOCK_MONOTONIC, &ts);
@@ -328,6 +331,9 @@ libusb_wait_for_event(libusb_context *ctx, struct time
 	}
 	err = pthread_cond_timedwait(&ctx->ctx_cond,
 	    &ctx->ctx_lock, &ts);
+	/* try to grab polling of actual events, if any */
+	if (ctx->ctx_handler == NO_THREAD)
+		ctx->ctx_handler = pthread_self();
 
 	if (err == ETIMEDOUT)
 		return (1);