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![Anton Vorontsov](/assets/img/avatar_default.png)
This patch fixes following sparse warnings: include/linux/kfifo.h:127:25: warning: Using plain integer as NULL pointer kernel/kfifo.c:83:21: warning: Using plain integer as NULL pointer Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Acked-by: Stefani Seibold <stefani@seibold.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
445 lines
11 KiB
C
445 lines
11 KiB
C
/*
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* A generic kernel FIFO implementation.
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*
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* Copyright (C) 2009 Stefani Seibold <stefani@seibold.net>
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* Copyright (C) 2004 Stelian Pop <stelian@popies.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/kfifo.h>
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#include <linux/log2.h>
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#include <linux/uaccess.h>
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static void _kfifo_init(struct kfifo *fifo, void *buffer,
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unsigned int size)
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{
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fifo->buffer = buffer;
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fifo->size = size;
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kfifo_reset(fifo);
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}
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/**
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* kfifo_init - initialize a FIFO using a preallocated buffer
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* @fifo: the fifo to assign the buffer
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* @buffer: the preallocated buffer to be used.
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* @size: the size of the internal buffer, this has to be a power of 2.
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*
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*/
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void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size)
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{
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/* size must be a power of 2 */
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BUG_ON(!is_power_of_2(size));
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_kfifo_init(fifo, buffer, size);
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}
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EXPORT_SYMBOL(kfifo_init);
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/**
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* kfifo_alloc - allocates a new FIFO internal buffer
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* @fifo: the fifo to assign then new buffer
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* @size: the size of the buffer to be allocated, this have to be a power of 2.
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* @gfp_mask: get_free_pages mask, passed to kmalloc()
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*
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* This function dynamically allocates a new fifo internal buffer
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*
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* The size will be rounded-up to a power of 2.
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* The buffer will be release with kfifo_free().
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* Return 0 if no error, otherwise the an error code
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*/
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int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask)
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{
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unsigned char *buffer;
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/*
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* round up to the next power of 2, since our 'let the indices
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* wrap' technique works only in this case.
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*/
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if (!is_power_of_2(size)) {
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BUG_ON(size > 0x80000000);
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size = roundup_pow_of_two(size);
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}
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buffer = kmalloc(size, gfp_mask);
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if (!buffer) {
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_kfifo_init(fifo, NULL, 0);
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return -ENOMEM;
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}
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_kfifo_init(fifo, buffer, size);
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return 0;
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}
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EXPORT_SYMBOL(kfifo_alloc);
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/**
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* kfifo_free - frees the FIFO internal buffer
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* @fifo: the fifo to be freed.
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*/
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void kfifo_free(struct kfifo *fifo)
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{
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kfree(fifo->buffer);
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_kfifo_init(fifo, NULL, 0);
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}
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EXPORT_SYMBOL(kfifo_free);
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/**
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* kfifo_skip - skip output data
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* @fifo: the fifo to be used.
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* @len: number of bytes to skip
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*/
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void kfifo_skip(struct kfifo *fifo, unsigned int len)
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{
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if (len < kfifo_len(fifo)) {
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__kfifo_add_out(fifo, len);
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return;
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}
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kfifo_reset_out(fifo);
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}
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EXPORT_SYMBOL(kfifo_skip);
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static inline void __kfifo_in_data(struct kfifo *fifo,
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const void *from, unsigned int len, unsigned int off)
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{
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unsigned int l;
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/*
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* Ensure that we sample the fifo->out index -before- we
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* start putting bytes into the kfifo.
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*/
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smp_mb();
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off = __kfifo_off(fifo, fifo->in + off);
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/* first put the data starting from fifo->in to buffer end */
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l = min(len, fifo->size - off);
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memcpy(fifo->buffer + off, from, l);
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/* then put the rest (if any) at the beginning of the buffer */
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memcpy(fifo->buffer, from + l, len - l);
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}
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static inline void __kfifo_out_data(struct kfifo *fifo,
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void *to, unsigned int len, unsigned int off)
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{
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unsigned int l;
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/*
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* Ensure that we sample the fifo->in index -before- we
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* start removing bytes from the kfifo.
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*/
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smp_rmb();
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off = __kfifo_off(fifo, fifo->out + off);
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/* first get the data from fifo->out until the end of the buffer */
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l = min(len, fifo->size - off);
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memcpy(to, fifo->buffer + off, l);
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/* then get the rest (if any) from the beginning of the buffer */
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memcpy(to + l, fifo->buffer, len - l);
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}
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static inline int __kfifo_from_user_data(struct kfifo *fifo,
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const void __user *from, unsigned int len, unsigned int off,
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unsigned *lenout)
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{
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unsigned int l;
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int ret;
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/*
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* Ensure that we sample the fifo->out index -before- we
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* start putting bytes into the kfifo.
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*/
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smp_mb();
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off = __kfifo_off(fifo, fifo->in + off);
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/* first put the data starting from fifo->in to buffer end */
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l = min(len, fifo->size - off);
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ret = copy_from_user(fifo->buffer + off, from, l);
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if (unlikely(ret)) {
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*lenout = ret;
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return -EFAULT;
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}
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*lenout = l;
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/* then put the rest (if any) at the beginning of the buffer */
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ret = copy_from_user(fifo->buffer, from + l, len - l);
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*lenout += ret ? ret : len - l;
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return ret ? -EFAULT : 0;
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}
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static inline int __kfifo_to_user_data(struct kfifo *fifo,
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void __user *to, unsigned int len, unsigned int off, unsigned *lenout)
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{
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unsigned int l;
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int ret;
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/*
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* Ensure that we sample the fifo->in index -before- we
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* start removing bytes from the kfifo.
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*/
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smp_rmb();
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off = __kfifo_off(fifo, fifo->out + off);
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/* first get the data from fifo->out until the end of the buffer */
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l = min(len, fifo->size - off);
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ret = copy_to_user(to, fifo->buffer + off, l);
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*lenout = l;
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if (unlikely(ret)) {
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*lenout -= ret;
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return -EFAULT;
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}
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/* then get the rest (if any) from the beginning of the buffer */
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len -= l;
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ret = copy_to_user(to + l, fifo->buffer, len);
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if (unlikely(ret)) {
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*lenout += len - ret;
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return -EFAULT;
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}
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*lenout += len;
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return 0;
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}
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unsigned int __kfifo_in_n(struct kfifo *fifo,
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const void *from, unsigned int len, unsigned int recsize)
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{
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if (kfifo_avail(fifo) < len + recsize)
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return len + 1;
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__kfifo_in_data(fifo, from, len, recsize);
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return 0;
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}
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EXPORT_SYMBOL(__kfifo_in_n);
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/**
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* kfifo_in - puts some data into the FIFO
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* @fifo: the fifo to be used.
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* @from: the data to be added.
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* @len: the length of the data to be added.
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*
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* This function copies at most @len bytes from the @from buffer into
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* the FIFO depending on the free space, and returns the number of
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* bytes copied.
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*
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* Note that with only one concurrent reader and one concurrent
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* writer, you don't need extra locking to use these functions.
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*/
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unsigned int kfifo_in(struct kfifo *fifo, const void *from,
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unsigned int len)
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{
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len = min(kfifo_avail(fifo), len);
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__kfifo_in_data(fifo, from, len, 0);
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__kfifo_add_in(fifo, len);
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return len;
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}
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EXPORT_SYMBOL(kfifo_in);
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unsigned int __kfifo_in_generic(struct kfifo *fifo,
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const void *from, unsigned int len, unsigned int recsize)
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{
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return __kfifo_in_rec(fifo, from, len, recsize);
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}
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EXPORT_SYMBOL(__kfifo_in_generic);
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unsigned int __kfifo_out_n(struct kfifo *fifo,
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void *to, unsigned int len, unsigned int recsize)
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{
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if (kfifo_len(fifo) < len + recsize)
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return len;
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__kfifo_out_data(fifo, to, len, recsize);
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__kfifo_add_out(fifo, len + recsize);
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return 0;
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}
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EXPORT_SYMBOL(__kfifo_out_n);
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/**
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* kfifo_out - gets some data from the FIFO
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* @fifo: the fifo to be used.
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* @to: where the data must be copied.
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* @len: the size of the destination buffer.
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*
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* This function copies at most @len bytes from the FIFO into the
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* @to buffer and returns the number of copied bytes.
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*
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* Note that with only one concurrent reader and one concurrent
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* writer, you don't need extra locking to use these functions.
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*/
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unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len)
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{
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len = min(kfifo_len(fifo), len);
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__kfifo_out_data(fifo, to, len, 0);
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__kfifo_add_out(fifo, len);
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return len;
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}
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EXPORT_SYMBOL(kfifo_out);
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/**
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* kfifo_out_peek - copy some data from the FIFO, but do not remove it
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* @fifo: the fifo to be used.
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* @to: where the data must be copied.
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* @len: the size of the destination buffer.
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* @offset: offset into the fifo
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*
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* This function copies at most @len bytes at @offset from the FIFO
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* into the @to buffer and returns the number of copied bytes.
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* The data is not removed from the FIFO.
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*/
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unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len,
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unsigned offset)
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{
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len = min(kfifo_len(fifo), len + offset);
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__kfifo_out_data(fifo, to, len, offset);
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return len;
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}
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EXPORT_SYMBOL(kfifo_out_peek);
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unsigned int __kfifo_out_generic(struct kfifo *fifo,
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void *to, unsigned int len, unsigned int recsize,
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unsigned int *total)
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{
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return __kfifo_out_rec(fifo, to, len, recsize, total);
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}
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EXPORT_SYMBOL(__kfifo_out_generic);
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unsigned int __kfifo_from_user_n(struct kfifo *fifo,
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const void __user *from, unsigned int len, unsigned int recsize)
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{
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unsigned total;
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if (kfifo_avail(fifo) < len + recsize)
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return len + 1;
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__kfifo_from_user_data(fifo, from, len, recsize, &total);
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return total;
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}
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EXPORT_SYMBOL(__kfifo_from_user_n);
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/**
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* kfifo_from_user - puts some data from user space into the FIFO
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* @fifo: the fifo to be used.
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* @from: pointer to the data to be added.
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* @len: the length of the data to be added.
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* @total: the actual returned data length.
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*
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* This function copies at most @len bytes from the @from into the
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* FIFO depending and returns -EFAULT/0.
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*
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* Note that with only one concurrent reader and one concurrent
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* writer, you don't need extra locking to use these functions.
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*/
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int kfifo_from_user(struct kfifo *fifo,
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const void __user *from, unsigned int len, unsigned *total)
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{
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int ret;
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len = min(kfifo_avail(fifo), len);
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ret = __kfifo_from_user_data(fifo, from, len, 0, total);
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if (ret)
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return ret;
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__kfifo_add_in(fifo, len);
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return 0;
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}
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EXPORT_SYMBOL(kfifo_from_user);
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unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
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const void __user *from, unsigned int len, unsigned int recsize)
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{
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return __kfifo_from_user_rec(fifo, from, len, recsize);
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}
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EXPORT_SYMBOL(__kfifo_from_user_generic);
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unsigned int __kfifo_to_user_n(struct kfifo *fifo,
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void __user *to, unsigned int len, unsigned int reclen,
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unsigned int recsize)
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{
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unsigned int ret, total;
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if (kfifo_len(fifo) < reclen + recsize)
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return len;
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ret = __kfifo_to_user_data(fifo, to, reclen, recsize, &total);
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if (likely(ret == 0))
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__kfifo_add_out(fifo, reclen + recsize);
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return total;
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}
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EXPORT_SYMBOL(__kfifo_to_user_n);
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/**
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* kfifo_to_user - gets data from the FIFO and write it to user space
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* @fifo: the fifo to be used.
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* @to: where the data must be copied.
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* @len: the size of the destination buffer.
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* @lenout: pointer to output variable with copied data
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*
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* This function copies at most @len bytes from the FIFO into the
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* @to buffer and 0 or -EFAULT.
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*
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* Note that with only one concurrent reader and one concurrent
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* writer, you don't need extra locking to use these functions.
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*/
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int kfifo_to_user(struct kfifo *fifo,
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void __user *to, unsigned int len, unsigned *lenout)
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{
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int ret;
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len = min(kfifo_len(fifo), len);
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ret = __kfifo_to_user_data(fifo, to, len, 0, lenout);
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__kfifo_add_out(fifo, *lenout);
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return ret;
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}
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EXPORT_SYMBOL(kfifo_to_user);
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unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
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void __user *to, unsigned int len, unsigned int recsize,
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unsigned int *total)
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{
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return __kfifo_to_user_rec(fifo, to, len, recsize, total);
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}
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EXPORT_SYMBOL(__kfifo_to_user_generic);
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unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize)
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{
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if (recsize == 0)
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return kfifo_avail(fifo);
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return __kfifo_peek_n(fifo, recsize);
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}
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EXPORT_SYMBOL(__kfifo_peek_generic);
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void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize)
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{
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__kfifo_skip_rec(fifo, recsize);
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}
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EXPORT_SYMBOL(__kfifo_skip_generic);
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