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Commit 7e6c57e2 authored by Gilad Broner's avatar Gilad Broner
Browse files

Revert "media: dvb: Use fill count for dvb_ringbuffer" 



This reverts commit f3ba3f6a.

In order to sync on buffer state with SDMX, demux manipulates the
read/write pointers of dvb_ringbuffer directly to account for new
data from SDMX. When dvb_ringbuffer is using fill count internally,
updating the read/write pointers does not affect the fill count
and so buffer is out of sync with SDMX.

Change-Id: I70828ba3337e49c53da67862b20d5f2c119f4271
Signed-off-by: default avatarGilad Broner <gbroner@codeaurora.org>
parent 5e741700

drivers/media/dvb-core/dvb_ringbuffer.c

+17 −19
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
 * Copyright (C) 2003 Oliver Endriss

 * Copyright (C) 2004 Andrew de Quincey

 *

 * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.

 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.

 *

 * based on code originally found in av7110.c & dvb_ci.c:

 * Copyright (C) 1999-2003 Ralph  Metzler
@@ -49,7 +49,6 @@ void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len) 
	rbuf->data=data;

	rbuf->size=len;

	rbuf->error=0;

	atomic_set(&rbuf->fill, 0);



	init_waitqueue_head(&rbuf->queue);
@@ -58,23 +57,33 @@ void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len) 






int dvb_ringbuffer_empty(const struct dvb_ringbuffer *rbuf)

int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)

{

	return (atomic_read(&rbuf->fill) == 0);

	return (rbuf->pread == rbuf->pwrite);

}







ssize_t dvb_ringbuffer_free(const struct dvb_ringbuffer *rbuf)

ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)

{

	return rbuf->size - atomic_read(&rbuf->fill);

	ssize_t free;



	free = rbuf->pread - rbuf->pwrite;

	if (free <= 0)

		free += rbuf->size;

	return free-1;

}







ssize_t dvb_ringbuffer_avail(const struct dvb_ringbuffer *rbuf)

ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)

{

	return atomic_read(&rbuf->fill);

	ssize_t avail;



	avail = rbuf->pwrite - rbuf->pread;

	if (avail < 0)

		avail += rbuf->size;

	return avail;

}
@@ -83,7 +92,6 @@ void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf) 
{

	rbuf->pread = rbuf->pwrite;

	rbuf->error = 0;

	atomic_set(&rbuf->fill, 0);

}

EXPORT_SYMBOL(dvb_ringbuffer_flush);
@@ -91,9 +99,7 @@ void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf) 
{

	rbuf->pread = rbuf->pwrite = 0;

	rbuf->error = 0;

	atomic_set(&rbuf->fill, 0);

}

EXPORT_SYMBOL(dvb_ringbuffer_reset);



void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)

{
@@ -118,13 +124,11 @@ ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, si 
		buf += split;

		todo -= split;

		rbuf->pread = 0;

		atomic_sub(split, &rbuf->fill);

	}

	if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))

		return -EFAULT;



	rbuf->pread = (rbuf->pread + todo) % rbuf->size;

	atomic_sub(todo, &rbuf->fill);



	return len;

}
@@ -140,12 +144,10 @@ void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len) 
		buf += split;

		todo -= split;

		rbuf->pread = 0;

		atomic_sub(split, &rbuf->fill);

	}

	memcpy(buf, rbuf->data+rbuf->pread, todo);



	rbuf->pread = (rbuf->pread + todo) % rbuf->size;

	atomic_sub(todo, &rbuf->fill);

}
@@ -161,11 +163,9 @@ ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t 
		buf += split;

		todo -= split;

		rbuf->pwrite = 0;

		atomic_add(split, &rbuf->fill);

	}

	memcpy(rbuf->data+rbuf->pwrite, buf, todo);

	rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;

	atomic_add(todo, &rbuf->fill);



	return len;

}
@@ -187,7 +187,6 @@ ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf, 
		buf += split;

		todo -= split;

		rbuf->pwrite = 0;

		atomic_add(split, &rbuf->fill);

	}



	if (copy_from_user(rbuf->data + rbuf->pwrite, buf, todo)) {
@@ -196,7 +195,6 @@ ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf, 
	}



	rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;

	atomic_add(todo, &rbuf->fill);



	return len;

}

drivers/media/dvb-core/dvb_ringbuffer.h

+12 −16
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
 * Copyright (C) 2003 Oliver Endriss

 * Copyright (C) 2004 Andrew de Quincey

 *

 * Copyright (c) 2012,2014, The Linux Foundation. All rights reserved.

 * Copyright (c) 2012, The Linux Foundation. All rights reserved.

 *

 * based on code originally found in av7110.c & dvb_ci.c:

 * Copyright (C) 1999-2003 Ralph Metzler & Marcus Metzler
@@ -37,7 +37,6 @@ struct dvb_ringbuffer { 
	ssize_t           size;

	ssize_t           pread;

	ssize_t           pwrite;

	atomic_t	fill;

	int               error;



	wait_queue_head_t queue;
@@ -80,13 +79,13 @@ struct dvb_ringbuffer { 
extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len);



/* test whether buffer is empty */

extern int dvb_ringbuffer_empty(const struct dvb_ringbuffer *rbuf);

extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);



/* return the number of free bytes in the buffer */

extern ssize_t dvb_ringbuffer_free(const struct dvb_ringbuffer *rbuf);

extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf);



/* return the number of bytes waiting in the buffer */

extern ssize_t dvb_ringbuffer_avail(const struct dvb_ringbuffer *rbuf);

extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);





/*
@@ -110,13 +109,11 @@ extern void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf); 


/* advance read ptr by <num> bytes */

#define DVB_RINGBUFFER_SKIP(rbuf,num)	\

	{ (rbuf)->pread = ((rbuf)->pread+(num))%(rbuf)->size;	\

	atomic_sub((num), &(rbuf)->fill); }

			(rbuf)->pread = ((rbuf)->pread+(num))%(rbuf)->size



/* advance write ptr by <num> bytes */

#define DVB_RINGBUFFER_PUSH(rbuf, num)	\

	{ ((rbuf)->pwrite = (((rbuf)->pwrite+(num))%(rbuf)->size));	\

	atomic_add((num), &(rbuf)->fill); }

			((rbuf)->pwrite = (((rbuf)->pwrite+(num))%(rbuf)->size))



/*

** read <len> bytes from ring buffer into <buf>
@@ -134,8 +131,7 @@ extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, 
/* write single byte to ring buffer */

#define DVB_RINGBUFFER_WRITE_BYTE(rbuf,byte)	\

			{ (rbuf)->data[(rbuf)->pwrite]=(byte); \

			(rbuf)->pwrite = ((rbuf)->pwrite+1)%(rbuf)->size; \

			atomic_inc(&(rbuf)->fill); }

			(rbuf)->pwrite = ((rbuf)->pwrite+1)%(rbuf)->size; }

/*

** write <len> bytes to ring buffer

** <usermem> specifies whether <buf> resides in user space

include/uapi/linux/dvb/dmx.h

+4 −1
Original line number Diff line number Diff line
@@ -183,7 +183,10 @@ struct dmx_buffer_status { 
	/* fullness of buffer in bytes */

	unsigned int fullness;



	/* How many bytes are free */

	/*

	 * How many bytes are free

	 * It's the same as: size-fullness-1

	 */

	unsigned int free_bytes;



	/* read pointer offset in bytes */