| /* |
| * A generic kernel FIFO implementation. |
| * |
| * Copyright (C) 2009 Stefani Seibold <stefani@seibold.net> |
| * Copyright (C) 2004 Stelian Pop <stelian@popies.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/module.h> |
| #include <linux/slab.h> |
| #include <linux/err.h> |
| #include <linux/kfifo.h> |
| #include <linux/log2.h> |
| #include <linux/uaccess.h> |
| |
| static void _kfifo_init(struct kfifo *fifo, unsigned char *buffer, |
| unsigned int size) |
| { |
| fifo->buffer = buffer; |
| fifo->size = size; |
| |
| kfifo_reset(fifo); |
| } |
| |
| /** |
| * kfifo_init - initialize a FIFO using a preallocated buffer |
| * @fifo: the fifo to assign the buffer |
| * @buffer: the preallocated buffer to be used. |
| * @size: the size of the internal buffer, this have to be a power of 2. |
| * |
| */ |
| void kfifo_init(struct kfifo *fifo, unsigned char *buffer, unsigned int size) |
| { |
| /* size must be a power of 2 */ |
| BUG_ON(!is_power_of_2(size)); |
| |
| _kfifo_init(fifo, buffer, size); |
| } |
| EXPORT_SYMBOL(kfifo_init); |
| |
| /** |
| * kfifo_alloc - allocates a new FIFO internal buffer |
| * @fifo: the fifo to assign then new buffer |
| * @size: the size of the buffer to be allocated, this have to be a power of 2. |
| * @gfp_mask: get_free_pages mask, passed to kmalloc() |
| * |
| * This function dynamically allocates a new fifo internal buffer |
| * |
| * The size will be rounded-up to a power of 2. |
| * The buffer will be release with kfifo_free(). |
| * Return 0 if no error, otherwise the an error code |
| */ |
| int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask) |
| { |
| unsigned char *buffer; |
| |
| /* |
| * round up to the next power of 2, since our 'let the indices |
| * wrap' technique works only in this case. |
| */ |
| if (!is_power_of_2(size)) { |
| BUG_ON(size > 0x80000000); |
| size = roundup_pow_of_two(size); |
| } |
| |
| buffer = kmalloc(size, gfp_mask); |
| if (!buffer) { |
| _kfifo_init(fifo, 0, 0); |
| return -ENOMEM; |
| } |
| |
| _kfifo_init(fifo, buffer, size); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(kfifo_alloc); |
| |
| /** |
| * kfifo_free - frees the FIFO internal buffer |
| * @fifo: the fifo to be freed. |
| */ |
| void kfifo_free(struct kfifo *fifo) |
| { |
| kfree(fifo->buffer); |
| } |
| EXPORT_SYMBOL(kfifo_free); |
| |
| /** |
| * kfifo_skip - skip output data |
| * @fifo: the fifo to be used. |
| * @len: number of bytes to skip |
| */ |
| void kfifo_skip(struct kfifo *fifo, unsigned int len) |
| { |
| if (len < kfifo_len(fifo)) { |
| __kfifo_add_out(fifo, len); |
| return; |
| } |
| kfifo_reset_out(fifo); |
| } |
| 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. |
| * @from: the data to be added. |
| * @len: the length of the data to be added. |
| * |
| * This function copies at most @len bytes from the @from buffer into |
| * the FIFO depending on the free space, and returns the number of |
| * bytes copied. |
| * |
| * 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) |
| { |
| 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. |
| * @to: where the data must be copied. |
| * @len: the size of the destination buffer. |
| * |
| * This function copies at most @len bytes from the FIFO into the |
| * @to buffer and returns the number of copied bytes. |
| * |
| * 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) |
| { |
| 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. |
| * @from: pointer to the data to be added. |
| * @len: the length of the data to be added. |
| * |
| * This function copies at most @len bytes from the @from into the |
| * FIFO depending and returns the number of copied bytes. |
| * |
| * Note that with only one concurrent reader and one concurrent |
| * writer, you don't need extra locking to use these functions. |
| */ |
| unsigned int kfifo_from_user(struct kfifo *fifo, |
| const void __user *from, unsigned int len) |
| { |
| 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. |
| * @to: where the data must be copied. |
| * @len: the size of the destination buffer. |
| * |
| * This function copies at most @len bytes from the FIFO into the |
| * @to buffer and returns the number of copied bytes. |
| * |
| * Note that with only one concurrent reader and one concurrent |
| * writer, you don't need extra locking to use these functions. |
| */ |
| unsigned int kfifo_to_user(struct kfifo *fifo, |
| void __user *to, unsigned int len) |
| { |
| 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); |
| |