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kfifo: add record handling functions

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Add kfifo_in_rec() - puts some record data into the FIFO
 Add kfifo_out_rec() - gets some record data from the FIFO
 Add kfifo_from_user_rec() - puts some data from user space into the FIFO
 Add kfifo_to_user_rec() - gets data from the FIFO and write it to user space
 Add kfifo_peek_rec() - gets the size of the next FIFO record field
 Add kfifo_skip_rec() - skip the next fifo out record
 Add kfifo_avail_rec() - determinate the number of bytes available in a record FIFO

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stefani Seibold 2009-12-21 14:37:32 -08:00 committed by Linus Torvalds
parent a121f24acc
commit 86d4880313
2 changed files with 533 additions and 103 deletions
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330
include/linux/kfifo.h
View File

@ -278,4 +278,334 @@ static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off)
return off & (fifo->size - 1);
}
/**
* __kfifo_peek_n internal helper function for determinate the length of
* the next record in the fifo
*/
static inline unsigned int __kfifo_peek_n(struct kfifo *fifo,
unsigned int recsize)
{
#define __KFIFO_GET(fifo, off, shift) \
((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] << (shift))
unsigned int l;
l = __KFIFO_GET(fifo, 0, 0);
if (--recsize)
l |= __KFIFO_GET(fifo, 1, 8);
return l;
#undef __KFIFO_GET
}
/**
* __kfifo_poke_n internal helper function for storing the length of
* the next record into the fifo
*/
static inline void __kfifo_poke_n(struct kfifo *fifo,
unsigned int recsize, unsigned int n)
{
#define __KFIFO_PUT(fifo, off, val, shift) \
( \
(fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = \
(unsigned char)((val) >> (shift)) \
)
__KFIFO_PUT(fifo, 0, n, 0);
if (--recsize)
__KFIFO_PUT(fifo, 1, n, 8);
#undef __KFIFO_PUT
}
/**
* __kfifo_in_... internal functions for put date into the fifo
* do not call it directly, use kfifo_in_rec() instead
*/
extern unsigned int __kfifo_in_n(struct kfifo *fifo,
const void *from, unsigned int n, unsigned int recsize);
extern unsigned int __kfifo_in_generic(struct kfifo *fifo,
const void *from, unsigned int n, unsigned int recsize);
static inline unsigned int __kfifo_in_rec(struct kfifo *fifo,
const void *from, unsigned int n, unsigned int recsize)
{
unsigned int ret;
ret = __kfifo_in_n(fifo, from, n, recsize);
if (likely(ret == 0)) {
if (recsize)
__kfifo_poke_n(fifo, recsize, n);
__kfifo_add_in(fifo, n + recsize);
}
return ret;
}
/**
* kfifo_in_rec - puts some record data into the FIFO
* @fifo: the fifo to be used.
* @from: the data to be added.
* @n: the length of the data to be added.
* @recsize: size of record field
*
* This function copies @n bytes from the @from into the FIFO and returns
* the number of bytes which cannot be copied.
* A returned value greater than the @n value means that the record doesn't
* fit into the buffer.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned int kfifo_in_rec(struct kfifo *fifo,
void *from, unsigned int n, unsigned int recsize)
{
if (!__builtin_constant_p(recsize))
return __kfifo_in_generic(fifo, from, n, recsize);
return __kfifo_in_rec(fifo, from, n, recsize);
}
/**
* __kfifo_out_... internal functions for get date from the fifo
* do not call it directly, use kfifo_out_rec() instead
*/
extern unsigned int __kfifo_out_n(struct kfifo *fifo,
void *to, unsigned int reclen, unsigned int recsize);
extern unsigned int __kfifo_out_generic(struct kfifo *fifo,
void *to, unsigned int n,
unsigned int recsize, unsigned int *total);
static inline unsigned int __kfifo_out_rec(struct kfifo *fifo,
void *to, unsigned int n, unsigned int recsize,
unsigned int *total)
{
unsigned int l;
if (!recsize) {
l = n;
if (total)
*total = l;
} else {
l = __kfifo_peek_n(fifo, recsize);
if (total)
*total = l;
if (n < l)
return l;
}
return __kfifo_out_n(fifo, to, l, recsize);
}
/**
* kfifo_out_rec - gets some record data from the FIFO
* @fifo: the fifo to be used.
* @to: where the data must be copied.
* @n: the size of the destination buffer.
* @recsize: size of record field
* @total: pointer where the total number of to copied bytes should stored
*
* This function copies at most @n bytes from the FIFO to @to and returns the
* number of bytes which cannot be copied.
* A returned value greater than the @n value means that the record doesn't
* fit into the @to buffer.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned int kfifo_out_rec(struct kfifo *fifo,
void *to, unsigned int n, unsigned int recsize,
unsigned int *total)
{
if (!__builtin_constant_p(recsize))
return __kfifo_out_generic(fifo, to, n, recsize, total);
return __kfifo_out_rec(fifo, to, n, recsize, total);
}
/**
* __kfifo_from_user_... internal functions for transfer from user space into
* the fifo. do not call it directly, use kfifo_from_user_rec() instead
*/
extern unsigned int __kfifo_from_user_n(struct kfifo *fifo,
const void __user *from, unsigned int n, unsigned int recsize);
extern unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
const void __user *from, unsigned int n, unsigned int recsize);
static inline unsigned int __kfifo_from_user_rec(struct kfifo *fifo,
const void __user *from, unsigned int n, unsigned int recsize)
{
unsigned int ret;
ret = __kfifo_from_user_n(fifo, from, n, recsize);
if (likely(ret == 0)) {
if (recsize)
__kfifo_poke_n(fifo, recsize, n);
__kfifo_add_in(fifo, n + recsize);
}
return ret;
}
/**
* kfifo_from_user_rec - puts some data from user space into the FIFO
* @fifo: the fifo to be used.
* @from: pointer to the data to be added.
* @n: the length of the data to be added.
* @recsize: size of record field
*
* This function copies @n bytes from the @from into the
* FIFO and returns the number of bytes which cannot be copied.
*
* If the returned value is equal or less the @n value, the copy_from_user()
* functions has failed. Otherwise the record doesn't fit into the buffer.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned int kfifo_from_user_rec(struct kfifo *fifo,
const void __user *from, unsigned int n, unsigned int recsize)
{
if (!__builtin_constant_p(recsize))
return __kfifo_from_user_generic(fifo, from, n, recsize);
return __kfifo_from_user_rec(fifo, from, n, recsize);
}
/**
* __kfifo_to_user_... internal functions for transfer fifo data into user space
* do not call it directly, use kfifo_to_user_rec() instead
*/
extern unsigned int __kfifo_to_user_n(struct kfifo *fifo,
void __user *to, unsigned int n, unsigned int reclen,
unsigned int recsize);
extern unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
void __user *to, unsigned int n, unsigned int recsize,
unsigned int *total);
static inline unsigned int __kfifo_to_user_rec(struct kfifo *fifo,
void __user *to, unsigned int n,
unsigned int recsize, unsigned int *total)
{
unsigned int l;
if (!recsize) {
l = n;
if (total)
*total = l;
} else {
l = __kfifo_peek_n(fifo, recsize);
if (total)
*total = l;
if (n < l)
return l;
}
return __kfifo_to_user_n(fifo, to, n, l, recsize);
}
/**
* kfifo_to_user_rec - gets data from the FIFO and write it to user space
* @fifo: the fifo to be used.
* @to: where the data must be copied.
* @n: the size of the destination buffer.
* @recsize: size of record field
* @total: pointer where the total number of to copied bytes should stored
*
* This function copies at most @n bytes from the FIFO to the @to.
* In case of an error, the function returns the number of bytes which cannot
* be copied.
* If the returned value is equal or less the @n value, the copy_to_user()
* functions has failed. Otherwise the record doesn't fit into the @to buffer.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned int kfifo_to_user_rec(struct kfifo *fifo,
void __user *to, unsigned int n, unsigned int recsize,
unsigned int *total)
{
if (!__builtin_constant_p(recsize))
return __kfifo_to_user_generic(fifo, to, n, recsize, total);
return __kfifo_to_user_rec(fifo, to, n, recsize, total);
}
/**
* __kfifo_peek_... internal functions for peek into the next fifo record
* do not call it directly, use kfifo_peek_rec() instead
*/
extern unsigned int __kfifo_peek_generic(struct kfifo *fifo,
unsigned int recsize);
/**
* kfifo_peek_rec - gets the size of the next FIFO record data
* @fifo: the fifo to be used.
* @recsize: size of record field
*
* This function returns the size of the next FIFO record in number of bytes
*/
static inline __must_check unsigned int kfifo_peek_rec(struct kfifo *fifo,
unsigned int recsize)
{
if (!__builtin_constant_p(recsize))
return __kfifo_peek_generic(fifo, recsize);
if (!recsize)
return kfifo_len(fifo);
return __kfifo_peek_n(fifo, recsize);
}
/**
* __kfifo_skip_... internal functions for skip the next fifo record
* do not call it directly, use kfifo_skip_rec() instead
*/
extern void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize);
static inline void __kfifo_skip_rec(struct kfifo *fifo,
unsigned int recsize)
{
unsigned int l;
if (recsize) {
l = __kfifo_peek_n(fifo, recsize);
if (l + recsize <= kfifo_len(fifo)) {
__kfifo_add_out(fifo, l + recsize);
return;
}
}
kfifo_reset_out(fifo);
}
/**
* kfifo_skip_rec - skip the next fifo out record
* @fifo: the fifo to be used.
* @recsize: size of record field
*
* This function skips the next FIFO record
*/
static inline void kfifo_skip_rec(struct kfifo *fifo,
unsigned int recsize)
{
if (!__builtin_constant_p(recsize))
__kfifo_skip_generic(fifo, recsize);
else
__kfifo_skip_rec(fifo, recsize);
}
/**
* kfifo_avail_rec - returns the number of bytes available in a record FIFO
* @fifo: the fifo to be used.
* @recsize: size of record field
*/
static inline __must_check unsigned int kfifo_avail_rec(struct kfifo *fifo,
unsigned int recsize)
{
unsigned int l = kfifo_size(fifo) - kfifo_len(fifo);
return (l > recsize) ? l - recsize : 0;
}
#endif

306
kernel/kfifo.c
View File

@ -115,6 +115,113 @@ void kfifo_skip(struct kfifo *fifo, unsigned int len)
}
EXPORT_SYMBOL(kfifo_skip);
static inline void __kfifo_in_data(struct kfifo *fifo,
const void *from, unsigned int len, unsigned int off)
{
unsigned int l;
/*
* Ensure that we sample the fifo->out index -before- we
* start putting bytes into the kfifo.
*/
smp_mb();
off = __kfifo_off(fifo, fifo->in + off);
/* first put the data starting from fifo->in to buffer end */
l = min(len, fifo->size - off);
memcpy(fifo->buffer + off, from, l);
/* then put the rest (if any) at the beginning of the buffer */
memcpy(fifo->buffer, from + l, len - l);
}
static inline void __kfifo_out_data(struct kfifo *fifo,
void *to, unsigned int len, unsigned int off)
{
unsigned int l;
/*
* Ensure that we sample the fifo->in index -before- we
* start removing bytes from the kfifo.
*/
smp_rmb();
off = __kfifo_off(fifo, fifo->out + off);
/* first get the data from fifo->out until the end of the buffer */
l = min(len, fifo->size - off);
memcpy(to, fifo->buffer + off, l);
/* then get the rest (if any) from the beginning of the buffer */
memcpy(to + l, fifo->buffer, len - l);
}
static inline unsigned int __kfifo_from_user_data(struct kfifo *fifo,
const void __user *from, unsigned int len, unsigned int off)
{
unsigned int l;
int ret;
/*
* Ensure that we sample the fifo->out index -before- we
* start putting bytes into the kfifo.
*/
smp_mb();
off = __kfifo_off(fifo, fifo->in + off);
/* first put the data starting from fifo->in to buffer end */
l = min(len, fifo->size - off);
ret = copy_from_user(fifo->buffer + off, from, l);
if (unlikely(ret))
return ret + len - l;
/* then put the rest (if any) at the beginning of the buffer */
return copy_from_user(fifo->buffer, from + l, len - l);
}
static inline unsigned int __kfifo_to_user_data(struct kfifo *fifo,
void __user *to, unsigned int len, unsigned int off)
{
unsigned int l;
int ret;
/*
* Ensure that we sample the fifo->in index -before- we
* start removing bytes from the kfifo.
*/
smp_rmb();
off = __kfifo_off(fifo, fifo->out + off);
/* first get the data from fifo->out until the end of the buffer */
l = min(len, fifo->size - off);
ret = copy_to_user(to, fifo->buffer + off, l);
if (unlikely(ret))
return ret + len - l;
/* then get the rest (if any) from the beginning of the buffer */
return copy_to_user(to + l, fifo->buffer, len - l);
}
unsigned int __kfifo_in_n(struct kfifo *fifo,
const void *from, unsigned int len, unsigned int recsize)
{
if (kfifo_avail(fifo) < len + recsize)
return len + 1;
__kfifo_in_data(fifo, from, len, recsize);
return 0;
}
EXPORT_SYMBOL(__kfifo_in_n);
/**
* kfifo_in - puts some data into the FIFO
* @fifo: the fifo to be used.
@ -128,36 +235,36 @@ EXPORT_SYMBOL(kfifo_skip);
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
unsigned int kfifo_in(struct kfifo *fifo,
const unsigned char *from, unsigned int len)
unsigned int kfifo_in(struct kfifo *fifo, const unsigned char *from,
unsigned int len)
{
unsigned int off;
unsigned int l;
len = min(len, fifo->size - fifo->in + fifo->out);
/*
* Ensure that we sample the fifo->out index -before- we
* start putting bytes into the kfifo.
*/
smp_mb();
off = __kfifo_off(fifo, fifo->in);
/* first put the data starting from fifo->in to buffer end */
l = min(len, fifo->size - off);
memcpy(fifo->buffer + off, from, l);
/* then put the rest (if any) at the beginning of the buffer */
memcpy(fifo->buffer, from + l, len - l);
len = min(kfifo_avail(fifo), len);
__kfifo_in_data(fifo, from, len, 0);
__kfifo_add_in(fifo, len);
return len;
}
EXPORT_SYMBOL(kfifo_in);
unsigned int __kfifo_in_generic(struct kfifo *fifo,
const void *from, unsigned int len, unsigned int recsize)
{
return __kfifo_in_rec(fifo, from, len, recsize);
}
EXPORT_SYMBOL(__kfifo_in_generic);
unsigned int __kfifo_out_n(struct kfifo *fifo,
void *to, unsigned int len, unsigned int recsize)
{
if (kfifo_len(fifo) < len + recsize)
return len;
__kfifo_out_data(fifo, to, len, recsize);
__kfifo_add_out(fifo, len + recsize);
return 0;
}
EXPORT_SYMBOL(__kfifo_out_n);
/**
* kfifo_out - gets some data from the FIFO
* @fifo: the fifo to be used.
@ -170,36 +277,35 @@ EXPORT_SYMBOL(kfifo_in);
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
unsigned int kfifo_out(struct kfifo *fifo,
unsigned char *to, unsigned int len)
unsigned int kfifo_out(struct kfifo *fifo, unsigned char *to, unsigned int len)
{
unsigned int off;
unsigned int l;
len = min(len, fifo->in - fifo->out);
/*
* Ensure that we sample the fifo->in index -before- we
* start removing bytes from the kfifo.
*/
smp_rmb();
off = __kfifo_off(fifo, fifo->out);
/* first get the data from fifo->out until the end of the buffer */
l = min(len, fifo->size - off);
memcpy(to, fifo->buffer + off, l);
/* then get the rest (if any) from the beginning of the buffer */
memcpy(to + l, fifo->buffer, len - l);
len = min(kfifo_len(fifo), len);
__kfifo_out_data(fifo, to, len, 0);
__kfifo_add_out(fifo, len);
return len;
}
EXPORT_SYMBOL(kfifo_out);
unsigned int __kfifo_out_generic(struct kfifo *fifo,
void *to, unsigned int len, unsigned int recsize,
unsigned int *total)
{
return __kfifo_out_rec(fifo, to, len, recsize, total);
}
EXPORT_SYMBOL(__kfifo_out_generic);
unsigned int __kfifo_from_user_n(struct kfifo *fifo,
const void __user *from, unsigned int len, unsigned int recsize)
{
if (kfifo_avail(fifo) < len + recsize)
return len + 1;
return __kfifo_from_user_data(fifo, from, len, recsize);
}
EXPORT_SYMBOL(__kfifo_from_user_n);
/**
* kfifo_from_user - puts some data from user space into the FIFO
* @fifo: the fifo to be used.
@ -215,40 +321,38 @@ EXPORT_SYMBOL(kfifo_out);
unsigned int kfifo_from_user(struct kfifo *fifo,
const void __user *from, unsigned int len)
{
unsigned int off;
unsigned int l;
int ret;
len = min(len, fifo->size - fifo->in + fifo->out);
/*
* Ensure that we sample the fifo->out index -before- we
* start putting bytes into the kfifo.
*/
smp_mb();
off = __kfifo_off(fifo, fifo->in);
/* first put the data starting from fifo->in to buffer end */
l = min(len, fifo->size - off);
ret = copy_from_user(fifo->buffer + off, from, l);
if (unlikely(ret))
return l - ret;
/* then put the rest (if any) at the beginning of the buffer */
ret = copy_from_user(fifo->buffer, from + l, len - l);
if (unlikely(ret))
return len - ret;
len = min(kfifo_avail(fifo), len);
len -= __kfifo_from_user_data(fifo, from, len, 0);
__kfifo_add_in(fifo, len);
return len;
}
EXPORT_SYMBOL(kfifo_from_user);
unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
const void __user *from, unsigned int len, unsigned int recsize)
{
return __kfifo_from_user_rec(fifo, from, len, recsize);
}
EXPORT_SYMBOL(__kfifo_from_user_generic);
unsigned int __kfifo_to_user_n(struct kfifo *fifo,
void __user *to, unsigned int len, unsigned int reclen,
unsigned int recsize)
{
unsigned int ret;
if (kfifo_len(fifo) < reclen + recsize)
return len;
ret = __kfifo_to_user_data(fifo, to, reclen, recsize);
if (likely(ret == 0))
__kfifo_add_out(fifo, reclen + recsize);
return ret;
}
EXPORT_SYMBOL(__kfifo_to_user_n);
/**
* kfifo_to_user - gets data from the FIFO and write it to user space
* @fifo: the fifo to be used.
@ -264,37 +368,33 @@ EXPORT_SYMBOL(kfifo_from_user);
unsigned int kfifo_to_user(struct kfifo *fifo,
void __user *to, unsigned int len)
{
unsigned int off;
unsigned int l;
int ret;
len = min(len, fifo->in - fifo->out);
/*
* Ensure that we sample the fifo->in index -before- we
* start removing bytes from the kfifo.
*/
smp_rmb();
off = __kfifo_off(fifo, fifo->out);
/* first get the data from fifo->out until the end of the buffer */
l = min(len, fifo->size - off);
ret = copy_to_user(to, fifo->buffer + off, l);
if (unlikely(ret))
return l - ret;
/* then get the rest (if any) from the beginning of the buffer */
ret = copy_to_user(to + l, fifo->buffer, len - l);
if (unlikely(ret))
return len - ret;
len = min(kfifo_len(fifo), len);
len -= __kfifo_to_user_data(fifo, to, len, 0);
__kfifo_add_out(fifo, len);
return len;
}
EXPORT_SYMBOL(kfifo_to_user);
unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
void __user *to, unsigned int len, unsigned int recsize,
unsigned int *total)
{
return __kfifo_to_user_rec(fifo, to, len, recsize, total);
}
EXPORT_SYMBOL(__kfifo_to_user_generic);
unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize)
{
if (recsize == 0)
return kfifo_avail(fifo);
return __kfifo_peek_n(fifo, recsize);
}
EXPORT_SYMBOL(__kfifo_peek_generic);
void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize)
{
__kfifo_skip_rec(fifo, recsize);
}
EXPORT_SYMBOL(__kfifo_skip_generic);