Release 4.11 drivers/media/dvb-core/dvb_ringbuffer.c

Directory: drivers/media/dvb-core
/*
 *
 * dvb_ringbuffer.c: ring buffer implementation for the dvb driver
 *
 * Copyright (C) 2003 Oliver Endriss
 * Copyright (C) 2004 Andrew de Quincey
 *
 * based on code originally found in av7110.c & dvb_ci.c:
 * Copyright (C) 1999-2003 Ralph  Metzler
 *                       & Marcus Metzler for convergence integrated media GmbH
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 */



#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/uaccess.h>

#include "dvb_ringbuffer.h"


#define PKT_READY 0

#define PKT_DISPOSED 1




void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
{
	rbuf->pread=rbuf->pwrite=0;
	rbuf->data=data;
	rbuf->size=len;
	rbuf->error=0;

	init_waitqueue_head(&rbuf->queue);

	spin_lock_init(&(rbuf->lock));
}



Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 55 87.30% 1 33.33%
Andreas Oberritter 6 9.52% 1 33.33%
Michael Hunold 2 3.17% 1 33.33%
Total 63 100.00% 3 100.00%



int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
{
	/* smp_load_acquire() to load write pointer on reader side
         * this pairs with smp_store_release() in dvb_ringbuffer_write(),
         * dvb_ringbuffer_write_user(), or dvb_ringbuffer_reset()
         *
         * for memory barriers also see Documentation/circular-buffers.txt
         */
	return (rbuf->pread == smp_load_acquire(&rbuf->pwrite));
}



Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 19 73.08% 1 33.33%
Soeren Moch 5 19.23% 1 33.33%
Michael Hunold 2 7.69% 1 33.33%
Total 26 100.00% 3 100.00%



ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
{
	ssize_t free;

	/* ACCESS_ONCE() to load read pointer on writer side
         * this pairs with smp_store_release() in dvb_ringbuffer_read(),
         * dvb_ringbuffer_read_user(), dvb_ringbuffer_flush(),
         * or dvb_ringbuffer_reset()
         */
	free = ACCESS_ONCE(rbuf->pread) - rbuf->pwrite;
	if (free <= 0)
		free += rbuf->size;
	return free-1;
}



Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 38 86.36% 1 33.33%
Soeren Moch 4 9.09% 1 33.33%
Michael Hunold 2 4.55% 1 33.33%
Total 44 100.00% 3 100.00%



ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
{
	ssize_t avail;

	/* smp_load_acquire() to load write pointer on reader side
         * this pairs with smp_store_release() in dvb_ringbuffer_write(),
         * dvb_ringbuffer_write_user(), or dvb_ringbuffer_reset()
         */
	avail = smp_load_acquire(&rbuf->pwrite) - rbuf->pread;
	if (avail < 0)
		avail += rbuf->size;
	return avail;
}



Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 36 83.72% 1 33.33%
Soeren Moch 5 11.63% 1 33.33%
Michael Hunold 2 4.65% 1 33.33%
Total 43 100.00% 3 100.00%



void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
{
	/* dvb_ringbuffer_flush() counts as read operation
         * smp_load_acquire() to load write pointer
         * smp_store_release() to update read pointer, this ensures that the
         * correct pointer is visible for subsequent dvb_ringbuffer_free()
         * calls on other cpu cores
         */
	smp_store_release(&rbuf->pread, smp_load_acquire(&rbuf->pwrite));
	rbuf->error = 0;
}
Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 15 45.45% 1 25.00%
Soeren Moch 10 30.30% 1 25.00%
Andreas Oberritter 6 18.18% 1 25.00%
Michael Hunold 2 6.06% 1 25.00%
Total 33 100.00% 4 100.00%


EXPORT_SYMBOL(dvb_ringbuffer_flush);



void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
{
	/* dvb_ringbuffer_reset() counts as read and write operation
         * smp_store_release() to update read pointer
         */
	smp_store_release(&rbuf->pread, 0);
	/* smp_store_release() to update write pointer */
	smp_store_release(&rbuf->pwrite, 0);
	rbuf->error = 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Andrea Odetti 24 63.16% 1 50.00%
Soeren Moch 14 36.84% 1 50.00%
Total 38 100.00% 2 100.00%



void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
{
	unsigned long flags;

	spin_lock_irqsave(&rbuf->lock, flags);
	dvb_ringbuffer_flush(rbuf);
	spin_unlock_irqrestore(&rbuf->lock, flags);

	wake_up(&rbuf->queue);
}

Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 45 95.74% 1 50.00%
Michael Hunold 2 4.26% 1 50.00%
Total 47 100.00% 2 100.00%



ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len)
{
	size_t todo = len;
	size_t split;

	split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
	if (split > 0) {
		if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
			return -EFAULT;
		buf += split;
		todo -= split;
		/* smp_store_release() for read pointer update to ensure
                 * that buf is not overwritten until read is complete,
                 * this pairs with ACCESS_ONCE() in dvb_ringbuffer_free()
                 */
		smp_store_release(&rbuf->pread, 0);
	}
	if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
		return -EFAULT;

	/* smp_store_release() to update read pointer, see above */
	smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size);

	return len;
}

Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 89 62.24% 1 25.00%
Al Viro 40 27.97% 1 25.00%
Soeren Moch 12 8.39% 1 25.00%
Michael Hunold 2 1.40% 1 25.00%
Total 143 100.00% 4 100.00%



void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len)
{
	size_t todo = len;
	size_t split;

	split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
	if (split > 0) {
		memcpy(buf, rbuf->data+rbuf->pread, split);
		buf += split;
		todo -= split;
		/* smp_store_release() for read pointer update to ensure
                 * that buf is not overwritten until read is complete,
                 * this pairs with ACCESS_ONCE() in dvb_ringbuffer_free()
                 */
		smp_store_release(&rbuf->pread, 0);
	}
	memcpy(buf, rbuf->data+rbuf->pread, todo);

	/* smp_store_release() to update read pointer, see above */
	smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size);
}


Contributors
Person Tokens Prop Commits CommitProp
Al Viro 62 48.82% 1 25.00%
Alan Cox 52 40.94% 1 25.00%
Soeren Moch 12 9.45% 1 25.00%
Andrew Morton 1 0.79% 1 25.00%
Total 127 100.00% 4 100.00%



ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
{
	size_t todo = len;
	size_t split;

	split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;

	if (split > 0) {
		memcpy(rbuf->data+rbuf->pwrite, buf, split);
		buf += split;
		todo -= split;
		/* smp_store_release() for write pointer update to ensure that
                 * written data is visible on other cpu cores before the pointer
                 * update, this pairs with smp_load_acquire() in
                 * dvb_ringbuffer_empty() or dvb_ringbuffer_avail()
                 */
		smp_store_release(&rbuf->pwrite, 0);
	}
	memcpy(rbuf->data+rbuf->pwrite, buf, todo);
	/* smp_store_release() for write pointer update, see above */
	smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size);

	return len;
}

Contributors
Person Tokens Prop Commits CommitProp
Alan Cox 116 88.55% 1 25.00%
Soeren Moch 12 9.16% 1 25.00%
Michael Hunold 2 1.53% 1 25.00%
Andrew Morton 1 0.76% 1 25.00%
Total 131 100.00% 4 100.00%



ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
				  const u8 __user *buf, size_t len)
{
	int status;
	size_t todo = len;
	size_t split;

	split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;

	if (split > 0) {
		status = copy_from_user(rbuf->data+rbuf->pwrite, buf, split);
		if (status)
			return len - todo;
		buf += split;
		todo -= split;
		/* smp_store_release() for write pointer update to ensure that
                 * written data is visible on other cpu cores before the pointer
                 * update, this pairs with smp_load_acquire() in
                 * dvb_ringbuffer_empty() or dvb_ringbuffer_avail()
                 */
		smp_store_release(&rbuf->pwrite, 0);
	}
	status = copy_from_user(rbuf->data+rbuf->pwrite, buf, todo);
	if (status)
		return len - todo;
	/* smp_store_release() for write pointer update, see above */
	smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size);

	return len;
}

Contributors
Person Tokens Prop Commits CommitProp
Mauro Carvalho Chehab 145 92.36% 1 50.00%
Soeren Moch 12 7.64% 1 50.00%
Total 157 100.00% 2 100.00%



ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
{
	int status;
	ssize_t oldpwrite = rbuf->pwrite;

	DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
	DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
	DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
	status = dvb_ringbuffer_write(rbuf, buf, len);

	if (status < 0) rbuf->pwrite = oldpwrite;
	return status;
}

Contributors
Person Tokens Prop Commits CommitProp
Michael Hunold 78 100.00% 1 100.00%
Total 78 100.00% 1 100.00%



ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx,
				int offset, u8 __user *buf, size_t len)
{
	size_t todo;
	size_t split;
	size_t pktlen;

	pktlen = rbuf->data[idx] << 8;
	pktlen |= rbuf->data[(idx + 1) % rbuf->size];
	if (offset > pktlen) return -EINVAL;
	if ((offset + len) > pktlen) len = pktlen - offset;

	idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
	todo = len;
	split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
	if (split > 0) {
		if (copy_to_user(buf, rbuf->data+idx, split))
			return -EFAULT;
		buf += split;
		todo -= split;
		idx = 0;
	}
	if (copy_to_user(buf, rbuf->data+idx, todo))
		return -EFAULT;

	return len;
}

Contributors
Person Tokens Prop Commits CommitProp
Michael Hunold 163 86.70% 1 50.00%
Al Viro 25 13.30% 1 50.00%
Total 188 100.00% 2 100.00%



ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
				int offset, u8* buf, size_t len)
{
	size_t todo;
	size_t split;
	size_t pktlen;

	pktlen = rbuf->data[idx] << 8;
	pktlen |= rbuf->data[(idx + 1) % rbuf->size];
	if (offset > pktlen) return -EINVAL;
	if ((offset + len) > pktlen) len = pktlen - offset;

	idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
	todo = len;
	split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
	if (split > 0) {
		memcpy(buf, rbuf->data+idx, split);
		buf += split;
		todo -= split;
		idx = 0;
	}
	memcpy(buf, rbuf->data+idx, todo);
	return len;
}

Contributors
Person Tokens Prop Commits CommitProp
Al Viro 137 78.29% 1 50.00%
Michael Hunold 38 21.71% 1 50.00%
Total 175 100.00% 2 100.00%



void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
{
	size_t pktlen;

	rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;

	// clean up disposed packets
	while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
		if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
			pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
			pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
			DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
		} else {
			// first packet is not disposed, so we stop cleaning now
			break;
		}
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Michael Hunold 92 100.00% 1 100.00%
Total 92 100.00% 1 100.00%



ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
{
	int consumed;
	int curpktlen;
	int curpktstatus;

	if (idx == -1) {
	       idx = rbuf->pread;
	} else {
		curpktlen = rbuf->data[idx] << 8;
		curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
		idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
	}

	consumed = (idx - rbuf->pread) % rbuf->size;

	while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {

		curpktlen = rbuf->data[idx] << 8;
		curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
		curpktstatus = rbuf->data[(idx + 2) % rbuf->size];

		if (curpktstatus == PKT_READY) {
			*pktlen = curpktlen;
			return idx;
		}

		consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
		idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
	}

	// no packets available
	return -1;
}



Contributors
Person Tokens Prop Commits CommitProp
Michael Hunold 201 100.00% 1 100.00%
Total 201 100.00% 1 100.00%


EXPORT_SYMBOL(dvb_ringbuffer_init);

EXPORT_SYMBOL(dvb_ringbuffer_empty);

EXPORT_SYMBOL(dvb_ringbuffer_free);

EXPORT_SYMBOL(dvb_ringbuffer_avail);

EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);

EXPORT_SYMBOL(dvb_ringbuffer_read_user);

EXPORT_SYMBOL(dvb_ringbuffer_read);

EXPORT_SYMBOL(dvb_ringbuffer_write);

EXPORT_SYMBOL(dvb_ringbuffer_write_user);
Overall Contributors
Person Tokens Prop Commits CommitProp
Michael Hunold 606 36.37% 3 21.43%
Alan Cox 503 30.19% 1 7.14%
Al Viro 269 16.15% 1 7.14%
Mauro Carvalho Chehab 150 9.00% 1 7.14%
Soeren Moch 86 5.16% 1 7.14%
Andrea Odetti 24 1.44% 1 7.14%
Andreas Oberritter 12 0.72% 1 7.14%
Andrew Morton 9 0.54% 2 14.29%
Oliver Endriss 5 0.30% 1 7.14%
Linus Torvalds 1 0.06% 1 7.14%
Sakari Ailus 1 0.06% 1 7.14%
Total 1666 100.00% 14 100.00%
Directory: drivers/media/dvb-core

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Person	Tokens	Prop	Commits	CommitProp
Alan Cox	55	87.30%	1	33.33%
Andreas Oberritter	6	9.52%	1	33.33%
Michael Hunold	2	3.17%	1	33.33%
Total	63	100.00%	3	100.00%
cregit-Linux how code gets into the kernel

Release 4.11 drivers/media/dvb-core/dvb_ringbuffer.c

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