linux/lib/kfifo.c

596 lines
12 KiB
C
Raw Normal View 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/dma-mapping.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kfifo.h>
#include <linux/log2.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/uaccess.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;
}
treewide: kmalloc() -> kmalloc_array() The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12 20:55:00 +00:00
fifo->data = kmalloc_array(esize, size, gfp_mask);
if (!fifo->data) {
fifo->mask = 0;
kfifo: move struct kfifo in place This is a new generic kernel FIFO implementation. The current kernel fifo API is not very widely used, because it has to many constrains. Only 17 files in the current 2.6.31-rc5 used it. FIFO's are like list's a very basic thing and a kfifo API which handles the most use case would save a lot of development time and memory resources. I think this are the reasons why kfifo is not in use: - The API is to simple, important functions are missing - A fifo can be only allocated dynamically - There is a requirement of a spinlock whether you need it or not - There is no support for data records inside a fifo So I decided to extend the kfifo in a more generic way without blowing up the API to much. The new API has the following benefits: - Generic usage: For kernel internal use and/or device driver. - Provide an API for the most use case. - Slim API: The whole API provides 25 functions. - Linux style habit. - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros - Direct copy_to_user from the fifo and copy_from_user into the fifo. - The kfifo itself is an in place member of the using data structure, this save an indirection access and does not waste the kernel allocator. - Lockless access: if only one reader and one writer is active on the fifo, which is the common use case, no additional locking is necessary. - Remove spinlock - give the user the freedom of choice what kind of locking to use if one is required. - Ability to handle records. Three type of records are supported: - Variable length records between 0-255 bytes, with a record size field of 1 bytes. - Variable length records between 0-65535 bytes, with a record size field of 2 bytes. - Fixed size records, which no record size field. - Preserve memory resource. - Performance! - Easy to use! This patch: Since most users want to have the kfifo as part of another object, reorganize the code to allow including struct kfifo in another data structure. This requires changing the kfifo_alloc and kfifo_init prototypes so that we pass an existing kfifo pointer into them. This patch changes the implementation and all existing users. [akpm@linux-foundation.org: fix warning] Signed-off-by: Stefani Seibold <stefani@seibold.net> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 22:37:26 +00:00
return -ENOMEM;
}
fifo->mask = size - 1;
kfifo: move struct kfifo in place This is a new generic kernel FIFO implementation. The current kernel fifo API is not very widely used, because it has to many constrains. Only 17 files in the current 2.6.31-rc5 used it. FIFO's are like list's a very basic thing and a kfifo API which handles the most use case would save a lot of development time and memory resources. I think this are the reasons why kfifo is not in use: - The API is to simple, important functions are missing - A fifo can be only allocated dynamically - There is a requirement of a spinlock whether you need it or not - There is no support for data records inside a fifo So I decided to extend the kfifo in a more generic way without blowing up the API to much. The new API has the following benefits: - Generic usage: For kernel internal use and/or device driver. - Provide an API for the most use case. - Slim API: The whole API provides 25 functions. - Linux style habit. - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros - Direct copy_to_user from the fifo and copy_from_user into the fifo. - The kfifo itself is an in place member of the using data structure, this save an indirection access and does not waste the kernel allocator. - Lockless access: if only one reader and one writer is active on the fifo, which is the common use case, no additional locking is necessary. - Remove spinlock - give the user the freedom of choice what kind of locking to use if one is required. - Ability to handle records. Three type of records are supported: - Variable length records between 0-255 bytes, with a record size field of 1 bytes. - Variable length records between 0-65535 bytes, with a record size field of 2 bytes. - Fixed size records, which no record size field. - Preserve memory resource. - Performance! - Easy to use! This patch: Since most users want to have the kfifo as part of another object, reorganize the code to allow including struct kfifo in another data structure. This requires changing the kfifo_alloc and kfifo_init prototypes so that we pass an existing kfifo pointer into them. This patch changes the implementation and all existing users. [akpm@linux-foundation.org: fix warning] Signed-off-by: Stefani Seibold <stefani@seibold.net> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 22:37:26 +00:00
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;
if (!is_power_of_2(size))
size = rounddown_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_linear(struct __kfifo *fifo,
unsigned int *tail, unsigned int n)
{
unsigned int size = fifo->mask + 1;
unsigned int off = fifo->out & fifo->mask;
if (tail)
*tail = off;
return min3(n, fifo->in - fifo->out, size - off);
}
EXPORT_SYMBOL(__kfifo_out_linear);
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 unsigned int setup_sgl_buf(struct __kfifo *fifo, struct scatterlist *sgl,
unsigned int data_offset, int nents,
unsigned int len, dma_addr_t dma)
{
const void *buf = fifo->data + data_offset;
if (!nents || !len)
return 0;
sg_set_buf(sgl, buf, len);
if (dma != DMA_MAPPING_ERROR) {
sg_dma_address(sgl) = dma + data_offset;
sg_dma_len(sgl) = len;
}
return 1;
}
static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
int nents, unsigned int len, unsigned int off, dma_addr_t dma)
{
unsigned int size = fifo->mask + 1;
unsigned int esize = fifo->esize;
unsigned int len_to_end;
unsigned int n;
off &= fifo->mask;
if (esize != 1) {
off *= esize;
size *= esize;
len *= esize;
}
len_to_end = min(len, size - off);
n = setup_sgl_buf(fifo, sgl, off, nents, len_to_end, dma);
n += setup_sgl_buf(fifo, sgl + n, 0, nents - n, len - len_to_end, dma);
return n;
}
unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
struct scatterlist *sgl, int nents, unsigned int len,
dma_addr_t dma)
{
unsigned int l;
l = kfifo_unused(fifo);
if (len > l)
len = l;
return setup_sgl(fifo, sgl, nents, len, fifo->in, dma);
}
EXPORT_SYMBOL(__kfifo_dma_in_prepare);
unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
struct scatterlist *sgl, int nents, unsigned int len,
dma_addr_t dma)
{
unsigned int l;
l = fifo->in - fifo->out;
if (len > l)
len = l;
return setup_sgl(fifo, sgl, nents, len, fifo->out, dma);
}
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 storing 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_linear_r(struct __kfifo *fifo,
unsigned int *tail, unsigned int n, size_t recsize)
{
if (fifo->in == fifo->out)
return 0;
if (tail)
*tail = fifo->out + recsize;
return min(n, __kfifo_peek_n(fifo, recsize));
}
EXPORT_SYMBOL(__kfifo_out_linear_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,
dma_addr_t dma)
{
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, dma);
}
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,
dma_addr_t dma)
{
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, dma);
}
EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);