staging/easycap: Make code re-entrant

In order to allow multiple EasyCAP dongles to operate simultaneously
without mutual interference all static variables have been eliminated
except for a persistent inventory of plugged-in dongles at module level.
Signed-off-by: NMike Thomas <rmthomas@sciolus.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/easycap/easycap.h

@@ -121,7 +121,7 @@
 #define EASYCAP_DRIVER_DESCRIPTION "easycapdc60"
 
 #define USB_SKEL_MINOR_BASE     192
-#define VIDEO_DEVICE_MANY 8
+#define DONGLE_MANY 8
 
 /*---------------------------------------------------------------------------*/
 /*
@@ -264,6 +264,17 @@ struct v4l2_format v4l2_format;
  */
 /*---------------------------------------------------------------------------*/
 struct easycap {
+int isdongle;
+
+/*vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv*/
+#if defined(EASYCAP_IS_VIDEODEV_CLIENT)
+struct video_device video_device;
+#if defined(EASYCAP_NEEDS_V4L2_DEVICE_H)
+struct v4l2_device v4l2_device;
+#endif /*EASYCAP_NEEDS_V4L2_DEVICE_H*/
+#endif /*EASYCAP_IS_VIDEODEV_CLIENT*/
+/*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^*/
+
 unsigned int audio_pages_per_fragment;
 unsigned int audio_bytes_per_fragment;
 unsigned int audio_buffer_page_many;
@@ -276,12 +287,6 @@ __s16 oldaudio;
 int ilk;
 bool microphone;
 
-/*vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv*/
-#if defined(EASYCAP_IS_VIDEODEV_CLIENT)
-struct video_device *pvideo_device;
-#endif /*EASYCAP_IS_VIDEODEV_CLIENT*/
-/*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^*/
-
 struct usb_device *pusb_device;
 struct usb_interface *pusb_interface;
 
@@ -306,7 +311,10 @@ int merit[180];
 struct timeval timeval0;
 struct timeval timeval1;
 struct timeval timeval2;
+struct timeval timeval3;
+struct timeval timeval6;
 struct timeval timeval7;
+struct timeval timeval8;
 long long int dnbydt;
 
 int    video_interface;
@@ -332,6 +340,13 @@ struct data_buffer \
 struct list_head urb_video_head;
 struct list_head *purb_video_head;
 
+__u8 cache[8];
+__u8 *pcache;
+int video_mt;
+int audio_mt;
+long long audio_bytes;
+__u32 isequence;
+
 int vma_many;
 
 /*---------------------------------------------------------------------------*/
@@ -530,6 +545,7 @@ int              set2to93(struct usb_device *);
 
 int              regset(struct usb_device *, __u16, __u16);
 int              regget(struct usb_device *, __u16, void *);
+int		isdongle(struct easycap *);
 /*---------------------------------------------------------------------------*/
 struct signed_div_result {
 long long int quotient;
@@ -557,20 +573,39 @@ unsigned long long int remainder;
 	} \
 } while (0)
 /*---------------------------------------------------------------------------*/
-
+/*
+ *  MACROS SAM(...) AND JOM(...) ALLOW DIAGNOSTIC OUTPUT TO BE TAGGED WITH
+ *  THE IDENTITY OF THE DONGLE TO WHICH IT APPLIES, BUT IF INVOKED WHEN THE
+ *  POINTER peasycap IS INVALID AN Oops IS LIKELY, AND ITS CAUSE MAY NOT BE
+ *  IMMEDIATELY OBVIOUS FROM A CASUAL READING OF THE SOURCE CODE.  BEWARE.
+*/
+/*---------------------------------------------------------------------------*/
 #define SAY(format, args...) do { \
-	printk(KERN_DEBUG "easycap: %s: " format, __func__, ##args); \
+	printk(KERN_DEBUG "easycap:: %s: " \
+			format, __func__, ##args); \
+} while (0)
+#define SAM(format, args...) do { \
+	printk(KERN_DEBUG "easycap::%i%s: " \
+			format, peasycap->isdongle, __func__, ##args);\
 } while (0)
-
 
 #if defined(EASYCAP_DEBUG)
 #define JOT(n, format, args...) do { \
 	if (n <= debug) { \
-		printk(KERN_DEBUG "easycap: %s: " format, __func__, ##args); \
+		printk(KERN_DEBUG "easycap:: %s: " \
+			format, __func__, ##args);\
 	} \
 } while (0)
+#define JOM(n, format, args...) do { \
+	if (n <= debug) { \
+		printk(KERN_DEBUG "easycap::%i%s: " \
+			format, peasycap->isdongle, __func__, ##args);\
+	} \
+} while (0)
+
 #else
 #define JOT(n, format, args...) do {} while (0)
+#define JOM(n, format, args...) do {} while (0)
 #endif /*EASYCAP_DEBUG*/
 
 #define MICROSECONDS(X, Y) \

drivers/staging/easycap/easycap_debug.h

 /*****************************************************************************
 *                                                                            *
-*  debug.h                                                           *
+*  easycap_debug.h                                                           *
 *                                                                            *
 *****************************************************************************/
 /*

drivers/staging/easycap/easycap_low.c

@@ -783,6 +783,12 @@ return usb_control_msg(pusb_device, usb_sndctrlpipe(pusb_device, 0), \
 		(int)50000);
 }
 /*****************************************************************************/
+int
+audio_setup(struct easycap *peasycap)
+{
+struct usb_device *pusb_device;
+unsigned char buffer[1];
+int rc, id1, id2;
 /*---------------------------------------------------------------------------*/
 /*
  *                                IMPORTANT:
@@ -791,20 +797,12 @@ return usb_control_msg(pusb_device, usb_sndctrlpipe(pusb_device, 0), \
  *  TO ENABLE AUDIO  THE VALUE 0x0200 MUST BE SENT.
  */
 /*---------------------------------------------------------------------------*/
-int
-audio_setup(struct easycap *peasycap)
-{
-struct usb_device *pusb_device;
-static __u8 request = 0x01;
-static __u8 requesttype = \
+const __u8 request = 0x01;
+const __u8 requesttype = \
 		(__u8)(USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
-
-static __u16 value_unmute = 0x0200;
-static __u16 index = 0x0301;
-
-static unsigned char buffer[1];
-static __u16 length = 1;
-int rc, id1, id2;
+const __u16 value_unmute = 0x0200;
+const __u16 index = 0x0301;
+const __u16 length = 1;
 
 if (NULL == peasycap)
 	return -EFAULT;

drivers/staging/easycap/easycap_testcard.c

@@ -157,7 +157,7 @@ for (i1 = 0;  i1 <= last;  i1++)
 		printf("%6i, ", i2);  printf("%6i\n};\n", i2);
 		}
 	}
-return(0);
+return 0;
 }
 -----------------------------------------------------------------------------*/
 int tones[2048] = {