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linux/lib/kfifo.c
Thomas Gleixner 74ba9207e1 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 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 general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  675 mass ave cambridge ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:36:45 +02:00

592 lines
12 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* A generic kernel FIFO implementation
*
* Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/log2.h>
#include <linux/uaccess.h>
#include <linux/kfifo.h>
/*
* internal helper to calculate the unused elements in a fifo
*/
static inline unsigned int kfifo_unused(struct __kfifo *fifo)
{
return (fifo->mask + 1) - (fifo->in - fifo->out);
}
int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
size_t esize, gfp_t gfp_mask)
{
/*
* round up to the next power of 2, since our 'let the indices
* wrap' technique works only in this case.
*/
size = roundup_pow_of_two(size);
fifo->in = 0;
fifo->out = 0;
fifo->esize = esize;
if (size < 2) {
fifo->data = NULL;
fifo->mask = 0;
return -EINVAL;
}
fifo->data = kmalloc_array(esize, size, gfp_mask);
if (!fifo->data) {
fifo->mask = 0;
return -ENOMEM;
}
fifo->mask = size - 1;
return 0;
}
EXPORT_SYMBOL(__kfifo_alloc);
void __kfifo_free(struct __kfifo *fifo)
{
kfree(fifo->data);
fifo->in = 0;
fifo->out = 0;
fifo->esize = 0;
fifo->data = NULL;
fifo->mask = 0;
}
EXPORT_SYMBOL(__kfifo_free);
int __kfifo_init(struct __kfifo *fifo, void *buffer,
unsigned int size, size_t esize)
{
size /= esize;
size = roundup_pow_of_two(size);
fifo->in = 0;
fifo->out = 0;
fifo->esize = esize;
fifo->data = buffer;
if (size < 2) {
fifo->mask = 0;
return -EINVAL;
}
fifo->mask = size - 1;
return 0;
}
EXPORT_SYMBOL(__kfifo_init);
static void kfifo_copy_in(struct __kfifo *fifo, const void *src,
unsigned int len, unsigned int off)
{
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
unsigned int l;
off &= fifo->mask;
if (esize != 1) {
off *= esize;
size *= esize;
len *= esize;
}
l = min(len, size - off);
memcpy(fifo->data + off, src, l);
memcpy(fifo->data, src + l, len - l);
/*
* make sure that the data in the fifo is up to date before
* incrementing the fifo->in index counter
*/
smp_wmb();
}
unsigned int __kfifo_in(struct __kfifo *fifo,
const void *buf, unsigned int len)
{
unsigned int l;
l = kfifo_unused(fifo);
if (len > l)
len = l;
kfifo_copy_in(fifo, buf, len, fifo->in);
fifo->in += len;
return len;
}
EXPORT_SYMBOL(__kfifo_in);
static void kfifo_copy_out(struct __kfifo *fifo, void *dst,
unsigned int len, unsigned int off)
{
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
unsigned int l;
off &= fifo->mask;
if (esize != 1) {
off *= esize;
size *= esize;
len *= esize;
}
l = min(len, size - off);
memcpy(dst, fifo->data + off, l);
memcpy(dst + l, fifo->data, len - l);
/*
* make sure that the data is copied before
* incrementing the fifo->out index counter
*/
smp_wmb();
}
unsigned int __kfifo_out_peek(struct __kfifo *fifo,
void *buf, unsigned int len)
{
unsigned int l;
l = fifo->in - fifo->out;
if (len > l)
len = l;
kfifo_copy_out(fifo, buf, len, fifo->out);
return len;
}
EXPORT_SYMBOL(__kfifo_out_peek);
unsigned int __kfifo_out(struct __kfifo *fifo,
void *buf, unsigned int len)
{
len = __kfifo_out_peek(fifo, buf, len);
fifo->out += len;
return len;
}
EXPORT_SYMBOL(__kfifo_out);
static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,
const void __user *from, unsigned int len, unsigned int off,
unsigned int *copied)
{
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
unsigned int l;
unsigned long ret;
off &= fifo->mask;
if (esize != 1) {
off *= esize;
size *= esize;
len *= esize;
}
l = min(len, size - off);
ret = copy_from_user(fifo->data + off, from, l);
if (unlikely(ret))
ret = DIV_ROUND_UP(ret + len - l, esize);
else {
ret = copy_from_user(fifo->data, from + l, len - l);
if (unlikely(ret))
ret = DIV_ROUND_UP(ret, esize);
}
/*
* make sure that the data in the fifo is up to date before
* incrementing the fifo->in index counter
*/
smp_wmb();
*copied = len - ret * esize;
/* return the number of elements which are not copied */
return ret;
}
int __kfifo_from_user(struct __kfifo *fifo, const void __user *from,
unsigned long len, unsigned int *copied)
{
unsigned int l;
unsigned long ret;
unsigned int esize = fifo->esize;
int err;
if (esize != 1)
len /= esize;
l = kfifo_unused(fifo);
if (len > l)
len = l;
ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);
if (unlikely(ret)) {
len -= ret;
err = -EFAULT;
} else
err = 0;
fifo->in += len;
return err;
}
EXPORT_SYMBOL(__kfifo_from_user);
static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to,
unsigned int len, unsigned int off, unsigned int *copied)
{
unsigned int l;
unsigned long ret;
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
off &= fifo->mask;
if (esize != 1) {
off *= esize;
size *= esize;
len *= esize;
}
l = min(len, size - off);
ret = copy_to_user(to, fifo->data + off, l);
if (unlikely(ret))
ret = DIV_ROUND_UP(ret + len - l, esize);
else {
ret = copy_to_user(to + l, fifo->data, len - l);
if (unlikely(ret))
ret = DIV_ROUND_UP(ret, esize);
}
/*
* make sure that the data is copied before
* incrementing the fifo->out index counter
*/
smp_wmb();
*copied = len - ret * esize;
/* return the number of elements which are not copied */
return ret;
}
int __kfifo_to_user(struct __kfifo *fifo, void __user *to,
unsigned long len, unsigned int *copied)
{
unsigned int l;
unsigned long ret;
unsigned int esize = fifo->esize;
int err;
if (esize != 1)
len /= esize;
l = fifo->in - fifo->out;
if (len > l)
len = l;
ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);
if (unlikely(ret)) {
len -= ret;
err = -EFAULT;
} else
err = 0;
fifo->out += len;
return err;
}
EXPORT_SYMBOL(__kfifo_to_user);
static int setup_sgl_buf(struct scatterlist *sgl, void *buf,
int nents, unsigned int len)
{
int n;
unsigned int l;
unsigned int off;
struct page *page;
if (!nents)
return 0;
if (!len)
return 0;
n = 0;
page = virt_to_page(buf);
off = offset_in_page(buf);
l = 0;
while (len >= l + PAGE_SIZE - off) {
struct page *npage;
l += PAGE_SIZE;
buf += PAGE_SIZE;
npage = virt_to_page(buf);
if (page_to_phys(page) != page_to_phys(npage) - l) {
sg_set_page(sgl, page, l - off, off);
sgl = sg_next(sgl);
if (++n == nents || sgl == NULL)
return n;
page = npage;
len -= l - off;
l = off = 0;
}
}
sg_set_page(sgl, page, len, off);
return n + 1;
}
static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
int nents, unsigned int len, unsigned int off)
{
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
unsigned int l;
unsigned int n;
off &= fifo->mask;
if (esize != 1) {
off *= esize;
size *= esize;
len *= esize;
}
l = min(len, size - off);
n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
return n;
}
unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
struct scatterlist *sgl, int nents, unsigned int len)
{
unsigned int l;
l = kfifo_unused(fifo);
if (len > l)
len = l;
return setup_sgl(fifo, sgl, nents, len, fifo->in);
}
EXPORT_SYMBOL(__kfifo_dma_in_prepare);
unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
struct scatterlist *sgl, int nents, unsigned int len)
{
unsigned int l;
l = fifo->in - fifo->out;
if (len > l)
len = l;
return setup_sgl(fifo, sgl, nents, len, fifo->out);
}
EXPORT_SYMBOL(__kfifo_dma_out_prepare);
unsigned int __kfifo_max_r(unsigned int len, size_t recsize)
{
unsigned int max = (1 << (recsize << 3)) - 1;
if (len > max)
return max;
return len;
}
EXPORT_SYMBOL(__kfifo_max_r);
#define __KFIFO_PEEK(data, out, mask) \
((data)[(out) & (mask)])
/*
* __kfifo_peek_n internal helper function for determinate the length of
* the next record in the fifo
*/
static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize)
{
unsigned int l;
unsigned int mask = fifo->mask;
unsigned char *data = fifo->data;
l = __KFIFO_PEEK(data, fifo->out, mask);
if (--recsize)
l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;
return l;
}
#define __KFIFO_POKE(data, in, mask, val) \
( \
(data)[(in) & (mask)] = (unsigned char)(val) \
)
/*
* __kfifo_poke_n internal helper function for storeing the length of
* the record into the fifo
*/
static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize)
{
unsigned int mask = fifo->mask;
unsigned char *data = fifo->data;
__KFIFO_POKE(data, fifo->in, mask, n);
if (recsize > 1)
__KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);
}
unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize)
{
return __kfifo_peek_n(fifo, recsize);
}
EXPORT_SYMBOL(__kfifo_len_r);
unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf,
unsigned int len, size_t recsize)
{
if (len + recsize > kfifo_unused(fifo))
return 0;
__kfifo_poke_n(fifo, len, recsize);
kfifo_copy_in(fifo, buf, len, fifo->in + recsize);
fifo->in += len + recsize;
return len;
}
EXPORT_SYMBOL(__kfifo_in_r);
static unsigned int kfifo_out_copy_r(struct __kfifo *fifo,
void *buf, unsigned int len, size_t recsize, unsigned int *n)
{
*n = __kfifo_peek_n(fifo, recsize);
if (len > *n)
len = *n;
kfifo_copy_out(fifo, buf, len, fifo->out + recsize);
return len;
}
unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,
unsigned int len, size_t recsize)
{
unsigned int n;
if (fifo->in == fifo->out)
return 0;
return kfifo_out_copy_r(fifo, buf, len, recsize, &n);
}
EXPORT_SYMBOL(__kfifo_out_peek_r);
unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
unsigned int len, size_t recsize)
{
unsigned int n;
if (fifo->in == fifo->out)
return 0;
len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);
fifo->out += n + recsize;
return len;
}
EXPORT_SYMBOL(__kfifo_out_r);
void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)
{
unsigned int n;
n = __kfifo_peek_n(fifo, recsize);
fifo->out += n + recsize;
}
EXPORT_SYMBOL(__kfifo_skip_r);
int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,
unsigned long len, unsigned int *copied, size_t recsize)
{
unsigned long ret;
len = __kfifo_max_r(len, recsize);
if (len + recsize > kfifo_unused(fifo)) {
*copied = 0;
return 0;
}
__kfifo_poke_n(fifo, len, recsize);
ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);
if (unlikely(ret)) {
*copied = 0;
return -EFAULT;
}
fifo->in += len + recsize;
return 0;
}
EXPORT_SYMBOL(__kfifo_from_user_r);
int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
unsigned long len, unsigned int *copied, size_t recsize)
{
unsigned long ret;
unsigned int n;
if (fifo->in == fifo->out) {
*copied = 0;
return 0;
}
n = __kfifo_peek_n(fifo, recsize);
if (len > n)
len = n;
ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);
if (unlikely(ret)) {
*copied = 0;
return -EFAULT;
}
fifo->out += n + recsize;
return 0;
}
EXPORT_SYMBOL(__kfifo_to_user_r);
unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
{
BUG_ON(!nents);
len = __kfifo_max_r(len, recsize);
if (len + recsize > kfifo_unused(fifo))
return 0;
return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
}
EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);
void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
unsigned int len, size_t recsize)
{
len = __kfifo_max_r(len, recsize);
__kfifo_poke_n(fifo, len, recsize);
fifo->in += len + recsize;
}
EXPORT_SYMBOL(__kfifo_dma_in_finish_r);
unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
{
BUG_ON(!nents);
len = __kfifo_max_r(len, recsize);
if (len + recsize > fifo->in - fifo->out)
return 0;
return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
}
EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);
void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize)
{
unsigned int len;
len = __kfifo_peek_n(fifo, recsize);
fifo->out += len + recsize;
}
EXPORT_SYMBOL(__kfifo_dma_out_finish_r);
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