diff options
Diffstat (limited to 'kernel/kfifo.c')
| -rw-r--r-- | kernel/kfifo.c | 408 |
1 files changed, 327 insertions, 81 deletions
diff --git a/kernel/kfifo.c b/kernel/kfifo.c index 3765ff3c1bbe..32c5c15d750d 100644 --- a/kernel/kfifo.c +++ b/kernel/kfifo.c @@ -1,6 +1,7 @@ /* - * A simple kernel FIFO implementation. + * 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 @@ -25,50 +26,48 @@ #include <linux/err.h> #include <linux/kfifo.h> #include <linux/log2.h> +#include <linux/uaccess.h> + +static void _kfifo_init(struct kfifo *fifo, void *buffer, + unsigned int size) +{ + fifo->buffer = buffer; + fifo->size = size; + + kfifo_reset(fifo); +} /** - * kfifo_init - allocates a new FIFO using a preallocated buffer + * 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. - * @gfp_mask: get_free_pages mask, passed to kmalloc() - * @lock: the lock to be used to protect the fifo buffer + * @size: the size of the internal buffer, this has to be a power of 2. * - * Do NOT pass the kfifo to kfifo_free() after use! Simply free the - * &struct kfifo with kfree(). */ -struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size, - gfp_t gfp_mask, spinlock_t *lock) +void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size) { - struct kfifo *fifo; - /* size must be a power of 2 */ BUG_ON(!is_power_of_2(size)); - fifo = kmalloc(sizeof(struct kfifo), gfp_mask); - if (!fifo) - return ERR_PTR(-ENOMEM); - - fifo->buffer = buffer; - fifo->size = size; - fifo->in = fifo->out = 0; - fifo->lock = lock; - - return fifo; + _kfifo_init(fifo, buffer, size); } EXPORT_SYMBOL(kfifo_init); /** - * kfifo_alloc - allocates a new FIFO and its internal buffer - * @size: the size of the internal buffer to be allocated. + * 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() - * @lock: the lock to be used to protect the fifo buffer + * + * 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 */ -struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock) +int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask) { unsigned char *buffer; - struct kfifo *ret; /* * round up to the next power of 2, since our 'let the indices @@ -80,48 +79,92 @@ struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock) } buffer = kmalloc(size, gfp_mask); - if (!buffer) - return ERR_PTR(-ENOMEM); - - ret = kfifo_init(buffer, size, gfp_mask, lock); + if (!buffer) { + _kfifo_init(fifo, 0, 0); + return -ENOMEM; + } - if (IS_ERR(ret)) - kfree(buffer); + _kfifo_init(fifo, buffer, size); - return ret; + return 0; } EXPORT_SYMBOL(kfifo_alloc); /** - * kfifo_free - frees the FIFO + * kfifo_free - frees the FIFO internal buffer * @fifo: the fifo to be freed. */ void kfifo_free(struct kfifo *fifo) { kfree(fifo->buffer); - kfree(fifo); } EXPORT_SYMBOL(kfifo_free); /** - * __kfifo_put - puts some data into the FIFO, no locking version + * kfifo_skip - skip output data * @fifo: the fifo to be used. - * @buffer: the data to be added. - * @len: the length of the data to be added. - * - * This function copies at most @len bytes from the @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. + * @len: number of bytes to skip */ -unsigned int __kfifo_put(struct kfifo *fifo, - const unsigned char *buffer, unsigned int len) +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; - 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 + 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 int __kfifo_from_user_data(struct kfifo *fifo, + const void __user *from, unsigned int len, unsigned int off, + unsigned *lenout) +{ + unsigned int l; + int ret; /* * Ensure that we sample the fifo->out index -before- we @@ -130,68 +173,271 @@ unsigned int __kfifo_put(struct kfifo *fifo, 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 - (fifo->in & (fifo->size - 1))); - memcpy(fifo->buffer + (fifo->in & (fifo->size - 1)), buffer, l); + l = min(len, fifo->size - off); + ret = copy_from_user(fifo->buffer + off, from, l); + if (unlikely(ret)) { + *lenout = ret; + return -EFAULT; + } + *lenout = l; /* then put the rest (if any) at the beginning of the buffer */ - memcpy(fifo->buffer, buffer + l, len - l); + ret = copy_from_user(fifo->buffer, from + l, len - l); + *lenout += ret ? ret : len - l; + return ret ? -EFAULT : 0; +} + +static inline int __kfifo_to_user_data(struct kfifo *fifo, + void __user *to, unsigned int len, unsigned int off, unsigned *lenout) +{ + unsigned int l; + int ret; /* - * Ensure that we add the bytes to the kfifo -before- - * we update the fifo->in index. + * Ensure that we sample the fifo->in index -before- we + * start removing bytes from the kfifo. */ - smp_wmb(); + 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); + *lenout = l; + if (unlikely(ret)) { + *lenout -= ret; + return -EFAULT; + } + + /* then get the rest (if any) from the beginning of the buffer */ + len -= l; + ret = copy_to_user(to + l, fifo->buffer, len); + if (unlikely(ret)) { + *lenout += len - ret; + return -EFAULT; + } + *lenout += len; + return 0; +} + +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); - fifo->in += len; +/** + * 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 void *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_put); +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_get - gets some data from the FIFO, no locking version + * kfifo_out - gets some data from the FIFO * @fifo: the fifo to be used. - * @buffer: where the data must be copied. + * @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 - * @buffer and returns the number of copied bytes. + * @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_get(struct kfifo *fifo, - unsigned char *buffer, unsigned int len) +unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len) { - unsigned int l; + len = min(kfifo_len(fifo), len); - len = min(len, fifo->in - fifo->out); + __kfifo_out_data(fifo, to, len, 0); + __kfifo_add_out(fifo, len); - /* - * Ensure that we sample the fifo->in index -before- we - * start removing bytes from the kfifo. - */ + return len; +} +EXPORT_SYMBOL(kfifo_out); - smp_rmb(); +/** + * kfifo_out_peek - copy some data from the FIFO, but do not remove it + * @fifo: the fifo to be used. + * @to: where the data must be copied. + * @len: the size of the destination buffer. + * @offset: offset into the fifo + * + * This function copies at most @len bytes at @offset from the FIFO + * into the @to buffer and returns the number of copied bytes. + * The data is not removed from the FIFO. + */ +unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len, + unsigned offset) +{ + len = min(kfifo_len(fifo), len + offset); - /* first get the data from fifo->out until the end of the buffer */ - l = min(len, fifo->size - (fifo->out & (fifo->size - 1))); - memcpy(buffer, fifo->buffer + (fifo->out & (fifo->size - 1)), l); + __kfifo_out_data(fifo, to, len, offset); + return len; +} +EXPORT_SYMBOL(kfifo_out_peek); - /* then get the rest (if any) from the beginning of the buffer */ - memcpy(buffer + l, fifo->buffer, len - l); +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); - /* - * Ensure that we remove the bytes from the kfifo -before- - * we update the fifo->out index. - */ +unsigned int __kfifo_from_user_n(struct kfifo *fifo, + const void __user *from, unsigned int len, unsigned int recsize) +{ + unsigned total; - smp_mb(); + if (kfifo_avail(fifo) < len + recsize) + return len + 1; - fifo->out += len; + __kfifo_from_user_data(fifo, from, len, recsize, &total); + return total; +} +EXPORT_SYMBOL(__kfifo_from_user_n); - return len; +/** + * 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 -EFAULT/0. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +int kfifo_from_user(struct kfifo *fifo, + const void __user *from, unsigned int len, unsigned *total) +{ + int ret; + len = min(kfifo_avail(fifo), len); + ret = __kfifo_from_user_data(fifo, from, len, 0, total); + if (ret) + return ret; + __kfifo_add_in(fifo, len); + return 0; } -EXPORT_SYMBOL(__kfifo_get); +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, total; + + if (kfifo_len(fifo) < reclen + recsize) + return len; + + ret = __kfifo_to_user_data(fifo, to, reclen, recsize, &total); + + if (likely(ret == 0)) + __kfifo_add_out(fifo, reclen + recsize); + + return total; +} +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. + @ @lenout: pointer to output variable with copied data + * + * This function copies at most @len bytes from the FIFO into the + * @to buffer and 0 or -EFAULT. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +int kfifo_to_user(struct kfifo *fifo, + void __user *to, unsigned int len, unsigned *lenout) +{ + int ret; + len = min(kfifo_len(fifo), len); + ret = __kfifo_to_user_data(fifo, to, len, 0, lenout); + __kfifo_add_out(fifo, *lenout); + return ret; +} +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); + |