V4L/DVB (7711): pvrusb2: Fix race on module unload
The pvrusb2 driver - for basically forever - was not enforcing a
proper module tear-down. Kernel threads are used inside the driver
and all must be gone before the module can be safely removed. This
changeset reimplements a chunk of pvrusb2-context.c to enforce this
correctly. Unfortunately this is not a simple fix. The new
implementation also cuts back on kernel thread usage; instead of there
being 1 control thread per instance now it's just 1 control thread
shared by all instances. (By dropping to a single thread then the
module exit function can block on its shutdown and the thread itself
can monitor and cleanly shut down all of the other instances first.)
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/pvrusb2/pvrusb2-main.c b/drivers/media/video/pvrusb2/pvrusb2-main.c
index 54d9f16..332aced 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-main.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-main.c
@@ -125,6 +125,12 @@
pvr2_trace(PVR2_TRACE_INIT,"pvr_init");
+ ret = pvr2_context_global_init();
+ if (ret != 0) {
+ pvr2_trace(PVR2_TRACE_INIT,"pvr_init failure code=%d",ret);
+ return ret;
+ }
+
#ifdef CONFIG_VIDEO_PVRUSB2_SYSFS
class_ptr = pvr2_sysfs_class_create();
#endif /* CONFIG_VIDEO_PVRUSB2_SYSFS */
@@ -136,6 +142,8 @@
if (pvrusb2_debug) info("Debug mask is %d (0x%x)",
pvrusb2_debug,pvrusb2_debug);
+ pvr2_trace(PVR2_TRACE_INIT,"pvr_init complete");
+
return ret;
}
@@ -148,6 +156,10 @@
#ifdef CONFIG_VIDEO_PVRUSB2_SYSFS
pvr2_sysfs_class_destroy(class_ptr);
#endif /* CONFIG_VIDEO_PVRUSB2_SYSFS */
+
+ pvr2_context_global_done();
+
+ pvr2_trace(PVR2_TRACE_INIT,"pvr_exit complete");
}
module_init(pvr_init);