cregit-Linux how code gets into the kernel

Release 4.14 lib/kfifo.c

Directory: lib
/*
 * A generic kernel FIFO implementation
 *
 * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
 *
 * 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.
 *
 */

#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); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold2268.75%266.67%
Stelian Pop1031.25%133.33%
Total32100.00%3100.00%


int __kfifo_alloc(struct __kfifo *fifo, unsigned int size, size_t esize, gfp_t gfp_mask) { /* * round down 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(size * esize, gfp_mask); if (!fifo->data) { fifo->mask = 0; return -ENOMEM; } fifo->mask = size - 1; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold7566.37%350.00%
Stelian Pop3631.86%116.67%
Martin Waitz10.88%116.67%
Al Viro10.88%116.67%
Total113100.00%6100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold3165.96%250.00%
Stelian Pop1429.79%125.00%
Anton Vorontsov24.26%125.00%
Total47100.00%4100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold6272.94%466.67%
Stelian Pop2225.88%116.67%
Paul E. McKenney11.18%116.67%
Total85100.00%6100.00%

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(); }

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PersonTokensPropCommitsCommitProp
Stefani Seibold9380.87%375.00%
Stelian Pop2219.13%125.00%
Total115100.00%4100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold5384.13%360.00%
Andi Kleen812.70%120.00%
Stelian Pop23.17%120.00%
Total63100.00%5100.00%

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(); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold9684.21%360.00%
Stelian Pop1513.16%120.00%
Andi Kleen32.63%120.00%
Total114100.00%5100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold59100.00%2100.00%
Total59100.00%2100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold3897.44%266.67%
Andi Kleen12.56%133.33%
Total39100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold18098.90%266.67%
Lars-Peter Clausen21.10%133.33%
Total182100.00%3100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold120100.00%1100.00%
Total120100.00%1100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold17998.90%150.00%
Lars-Peter Clausen21.10%150.00%
Total181100.00%2100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold122100.00%1100.00%
Total122100.00%1100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold190100.00%2100.00%
Total190100.00%2100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold132100.00%1100.00%
Total132100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold60100.00%1100.00%
Total60100.00%1100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold63100.00%1100.00%
Total63100.00%1100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold41100.00%1100.00%
Total41100.00%1100.00%

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; }

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PersonTokensPropCommitsCommitProp
Stefani Seibold74100.00%1100.00%
Total74100.00%1100.00%

#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); }

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PersonTokensPropCommitsCommitProp
Stefani Seibold71100.00%2100.00%
Total71100.00%2100.00%


unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize) { return __kfifo_peek_n(fifo, recsize); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold22100.00%2100.00%
Total22100.00%2100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold7198.61%266.67%
Andi Kleen11.39%133.33%
Total72100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Andi Kleen3551.47%150.00%
Stefani Seibold3348.53%150.00%
Total68100.00%2100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold54100.00%2100.00%
Total54100.00%2100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold6090.91%266.67%
Andi Kleen69.09%133.33%
Total66100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Andrea Righi34100.00%1100.00%
Total34100.00%1100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold11193.28%266.67%
Andi Kleen86.72%133.33%
Total119100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold12199.18%266.67%
Andi Kleen10.82%133.33%
Total122100.00%3100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold6893.15%250.00%
Himangi Saraogi34.11%125.00%
Andi Kleen22.74%125.00%
Total73100.00%4100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold43100.00%2100.00%
Total43100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold7396.05%266.67%
Himangi Saraogi33.95%133.33%
Total76100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold34100.00%2100.00%
Total34100.00%2100.00%

EXPORT_SYMBOL(__kfifo_dma_out_finish_r);

Overall Contributors

PersonTokensPropCommitsCommitProp
Stefani Seibold258090.62%630.00%
Stelian Pop1404.92%15.00%
Andi Kleen652.28%315.00%
Andrea Righi391.37%15.00%
Himangi Saraogi60.21%15.00%
Srinivas Kandagatla50.18%15.00%
Lars-Peter Clausen40.14%15.00%
Vignesh Babu20.07%15.00%
Anton Vorontsov20.07%15.00%
Al Viro10.04%15.00%
Paul Gortmaker10.04%15.00%
Paul E. McKenney10.04%15.00%
Martin Waitz10.04%15.00%
Total2847100.00%20100.00%
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