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592 lines
12 KiB
592 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* A generic kernel FIFO implementation |
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* |
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* Copyright (C) 2009/2010 Stefani Seibold <[email protected]> |
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*/ |
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|
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#include <linux/kernel.h> |
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#include <linux/export.h> |
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#include <linux/slab.h> |
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#include <linux/err.h> |
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#include <linux/log2.h> |
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#include <linux/uaccess.h> |
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#include <linux/kfifo.h> |
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|
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/* |
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* internal helper to calculate the unused elements in a fifo |
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*/ |
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static inline unsigned int kfifo_unused(struct __kfifo *fifo) |
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{ |
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return (fifo->mask + 1) - (fifo->in - fifo->out); |
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} |
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int __kfifo_alloc(struct __kfifo *fifo, unsigned int size, |
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size_t esize, gfp_t gfp_mask) |
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{ |
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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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size = roundup_pow_of_two(size); |
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fifo->in = 0; |
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fifo->out = 0; |
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fifo->esize = esize; |
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if (size < 2) { |
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fifo->data = NULL; |
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fifo->mask = 0; |
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return -EINVAL; |
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} |
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fifo->data = kmalloc_array(esize, size, gfp_mask); |
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if (!fifo->data) { |
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fifo->mask = 0; |
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return -ENOMEM; |
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} |
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fifo->mask = size - 1; |
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return 0; |
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} |
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EXPORT_SYMBOL(__kfifo_alloc); |
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void __kfifo_free(struct __kfifo *fifo) |
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{ |
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kfree(fifo->data); |
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fifo->in = 0; |
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fifo->out = 0; |
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fifo->esize = 0; |
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fifo->data = NULL; |
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fifo->mask = 0; |
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} |
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EXPORT_SYMBOL(__kfifo_free); |
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int __kfifo_init(struct __kfifo *fifo, void *buffer, |
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unsigned int size, size_t esize) |
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{ |
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size /= esize; |
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if (!is_power_of_2(size)) |
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size = rounddown_pow_of_two(size); |
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fifo->in = 0; |
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fifo->out = 0; |
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fifo->esize = esize; |
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fifo->data = buffer; |
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if (size < 2) { |
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fifo->mask = 0; |
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return -EINVAL; |
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} |
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fifo->mask = size - 1; |
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return 0; |
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} |
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EXPORT_SYMBOL(__kfifo_init); |
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static void kfifo_copy_in(struct __kfifo *fifo, const void *src, |
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unsigned int len, unsigned int off) |
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{ |
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unsigned int size = fifo->mask + 1; |
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unsigned int esize = fifo->esize; |
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unsigned int l; |
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off &= fifo->mask; |
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if (esize != 1) { |
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off *= esize; |
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size *= esize; |
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len *= esize; |
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} |
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l = min(len, size - off); |
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memcpy(fifo->data + off, src, l); |
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memcpy(fifo->data, src + l, len - l); |
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/* |
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* make sure that the data in the fifo is up to date before |
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* incrementing the fifo->in index counter |
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*/ |
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smp_wmb(); |
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} |
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unsigned int __kfifo_in(struct __kfifo *fifo, |
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const void *buf, unsigned int len) |
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{ |
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unsigned int l; |
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l = kfifo_unused(fifo); |
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if (len > l) |
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len = l; |
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kfifo_copy_in(fifo, buf, len, fifo->in); |
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fifo->in += len; |
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return len; |
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} |
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EXPORT_SYMBOL(__kfifo_in); |
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static void kfifo_copy_out(struct __kfifo *fifo, void *dst, |
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unsigned int len, unsigned int off) |
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{ |
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unsigned int size = fifo->mask + 1; |
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unsigned int esize = fifo->esize; |
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unsigned int l; |
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off &= fifo->mask; |
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if (esize != 1) { |
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off *= esize; |
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size *= esize; |
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len *= esize; |
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} |
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l = min(len, size - off); |
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memcpy(dst, fifo->data + off, l); |
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memcpy(dst + l, fifo->data, len - l); |
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/* |
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* make sure that the data is copied before |
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* incrementing the fifo->out index counter |
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*/ |
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smp_wmb(); |
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} |
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unsigned int __kfifo_out_peek(struct __kfifo *fifo, |
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void *buf, unsigned int len) |
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{ |
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unsigned int l; |
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l = fifo->in - fifo->out; |
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if (len > l) |
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len = l; |
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kfifo_copy_out(fifo, buf, len, fifo->out); |
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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(struct __kfifo *fifo, |
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void *buf, unsigned int len) |
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{ |
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len = __kfifo_out_peek(fifo, buf, len); |
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fifo->out += len; |
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return len; |
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} |
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EXPORT_SYMBOL(__kfifo_out); |
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static unsigned long kfifo_copy_from_user(struct __kfifo *fifo, |
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const void __user *from, unsigned int len, unsigned int off, |
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unsigned int *copied) |
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{ |
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unsigned int size = fifo->mask + 1; |
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unsigned int esize = fifo->esize; |
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unsigned int l; |
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unsigned long ret; |
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off &= fifo->mask; |
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if (esize != 1) { |
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off *= esize; |
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size *= esize; |
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len *= esize; |
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} |
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l = min(len, size - off); |
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ret = copy_from_user(fifo->data + off, from, l); |
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if (unlikely(ret)) |
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ret = DIV_ROUND_UP(ret + len - l, esize); |
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else { |
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ret = copy_from_user(fifo->data, from + l, len - l); |
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if (unlikely(ret)) |
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ret = DIV_ROUND_UP(ret, esize); |
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} |
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/* |
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* make sure that the data in the fifo is up to date before |
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* incrementing the fifo->in index counter |
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*/ |
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smp_wmb(); |
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*copied = len - ret * esize; |
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/* return the number of elements which are not copied */ |
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return ret; |
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} |
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int __kfifo_from_user(struct __kfifo *fifo, const void __user *from, |
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unsigned long len, unsigned int *copied) |
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{ |
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unsigned int l; |
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unsigned long ret; |
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unsigned int esize = fifo->esize; |
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int err; |
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if (esize != 1) |
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len /= esize; |
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l = kfifo_unused(fifo); |
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if (len > l) |
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len = l; |
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ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied); |
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if (unlikely(ret)) { |
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len -= ret; |
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err = -EFAULT; |
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} else |
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err = 0; |
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fifo->in += len; |
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return err; |
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} |
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EXPORT_SYMBOL(__kfifo_from_user); |
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static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to, |
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unsigned int len, unsigned int off, unsigned int *copied) |
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{ |
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unsigned int l; |
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unsigned long ret; |
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unsigned int size = fifo->mask + 1; |
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unsigned int esize = fifo->esize; |
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off &= fifo->mask; |
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if (esize != 1) { |
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off *= esize; |
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size *= esize; |
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len *= esize; |
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} |
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l = min(len, size - off); |
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ret = copy_to_user(to, fifo->data + off, l); |
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if (unlikely(ret)) |
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ret = DIV_ROUND_UP(ret + len - l, esize); |
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else { |
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ret = copy_to_user(to + l, fifo->data, len - l); |
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if (unlikely(ret)) |
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ret = DIV_ROUND_UP(ret, esize); |
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} |
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/* |
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* make sure that the data is copied before |
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* incrementing the fifo->out index counter |
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*/ |
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smp_wmb(); |
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*copied = len - ret * esize; |
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/* return the number of elements which are not copied */ |
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return ret; |
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} |
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int __kfifo_to_user(struct __kfifo *fifo, void __user *to, |
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unsigned long len, unsigned int *copied) |
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{ |
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unsigned int l; |
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unsigned long ret; |
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unsigned int esize = fifo->esize; |
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int err; |
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if (esize != 1) |
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len /= esize; |
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l = fifo->in - fifo->out; |
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if (len > l) |
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len = l; |
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ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied); |
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if (unlikely(ret)) { |
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len -= ret; |
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err = -EFAULT; |
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} else |
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err = 0; |
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fifo->out += len; |
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return err; |
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} |
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EXPORT_SYMBOL(__kfifo_to_user); |
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static int setup_sgl_buf(struct scatterlist *sgl, void *buf, |
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int nents, unsigned int len) |
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{ |
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int n; |
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unsigned int l; |
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unsigned int off; |
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struct page *page; |
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if (!nents) |
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return 0; |
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if (!len) |
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return 0; |
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n = 0; |
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page = virt_to_page(buf); |
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off = offset_in_page(buf); |
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l = 0; |
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while (len >= l + PAGE_SIZE - off) { |
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struct page *npage; |
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l += PAGE_SIZE; |
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buf += PAGE_SIZE; |
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npage = virt_to_page(buf); |
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if (page_to_phys(page) != page_to_phys(npage) - l) { |
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sg_set_page(sgl, page, l - off, off); |
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sgl = sg_next(sgl); |
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if (++n == nents || sgl == NULL) |
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return n; |
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page = npage; |
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len -= l - off; |
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l = off = 0; |
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} |
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} |
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sg_set_page(sgl, page, len, off); |
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return n + 1; |
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} |
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static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl, |
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int nents, unsigned int len, unsigned int off) |
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{ |
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unsigned int size = fifo->mask + 1; |
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unsigned int esize = fifo->esize; |
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unsigned int l; |
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unsigned int n; |
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off &= fifo->mask; |
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if (esize != 1) { |
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off *= esize; |
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size *= esize; |
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len *= esize; |
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} |
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l = min(len, size - off); |
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n = setup_sgl_buf(sgl, fifo->data + off, nents, l); |
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n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l); |
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return n; |
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} |
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unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo, |
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struct scatterlist *sgl, int nents, unsigned int len) |
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{ |
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unsigned int l; |
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l = kfifo_unused(fifo); |
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if (len > l) |
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len = l; |
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return setup_sgl(fifo, sgl, nents, len, fifo->in); |
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} |
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EXPORT_SYMBOL(__kfifo_dma_in_prepare); |
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unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo, |
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struct scatterlist *sgl, int nents, unsigned int len) |
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{ |
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unsigned int l; |
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l = fifo->in - fifo->out; |
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if (len > l) |
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len = l; |
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return setup_sgl(fifo, sgl, nents, len, fifo->out); |
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} |
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EXPORT_SYMBOL(__kfifo_dma_out_prepare); |
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unsigned int __kfifo_max_r(unsigned int len, size_t recsize) |
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{ |
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unsigned int max = (1 << (recsize << 3)) - 1; |
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if (len > max) |
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return max; |
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return len; |
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} |
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EXPORT_SYMBOL(__kfifo_max_r); |
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#define __KFIFO_PEEK(data, out, mask) \ |
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((data)[(out) & (mask)]) |
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/* |
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* __kfifo_peek_n internal helper function for determinate the length of |
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* the next record in the fifo |
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*/ |
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static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize) |
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{ |
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unsigned int l; |
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unsigned int mask = fifo->mask; |
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unsigned char *data = fifo->data; |
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l = __KFIFO_PEEK(data, fifo->out, mask); |
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if (--recsize) |
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l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8; |
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return l; |
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} |
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#define __KFIFO_POKE(data, in, mask, val) \ |
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( \ |
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(data)[(in) & (mask)] = (unsigned char)(val) \ |
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) |
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/* |
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* __kfifo_poke_n internal helper function for storing the length of |
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* the record into the fifo |
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*/ |
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static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize) |
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{ |
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unsigned int mask = fifo->mask; |
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unsigned char *data = fifo->data; |
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__KFIFO_POKE(data, fifo->in, mask, n); |
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if (recsize > 1) |
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__KFIFO_POKE(data, fifo->in + 1, mask, n >> 8); |
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} |
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unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize) |
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{ |
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return __kfifo_peek_n(fifo, recsize); |
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} |
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EXPORT_SYMBOL(__kfifo_len_r); |
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unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf, |
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unsigned int len, size_t recsize) |
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{ |
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if (len + recsize > kfifo_unused(fifo)) |
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return 0; |
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__kfifo_poke_n(fifo, len, recsize); |
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kfifo_copy_in(fifo, buf, len, fifo->in + recsize); |
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fifo->in += len + recsize; |
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return len; |
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} |
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EXPORT_SYMBOL(__kfifo_in_r); |
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static unsigned int kfifo_out_copy_r(struct __kfifo *fifo, |
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void *buf, unsigned int len, size_t recsize, unsigned int *n) |
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{ |
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*n = __kfifo_peek_n(fifo, recsize); |
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if (len > *n) |
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len = *n; |
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kfifo_copy_out(fifo, buf, len, fifo->out + recsize); |
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return len; |
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} |
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unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf, |
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unsigned int len, size_t recsize) |
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{ |
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unsigned int n; |
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if (fifo->in == fifo->out) |
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return 0; |
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return kfifo_out_copy_r(fifo, buf, len, recsize, &n); |
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} |
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EXPORT_SYMBOL(__kfifo_out_peek_r); |
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unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf, |
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unsigned int len, size_t recsize) |
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{ |
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unsigned int n; |
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if (fifo->in == fifo->out) |
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return 0; |
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len = kfifo_out_copy_r(fifo, buf, len, recsize, &n); |
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fifo->out += n + recsize; |
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return len; |
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} |
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EXPORT_SYMBOL(__kfifo_out_r); |
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void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize) |
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{ |
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unsigned int n; |
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n = __kfifo_peek_n(fifo, recsize); |
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fifo->out += n + recsize; |
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} |
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EXPORT_SYMBOL(__kfifo_skip_r); |
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int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from, |
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unsigned long len, unsigned int *copied, size_t recsize) |
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{ |
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unsigned long ret; |
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len = __kfifo_max_r(len, recsize); |
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if (len + recsize > kfifo_unused(fifo)) { |
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*copied = 0; |
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return 0; |
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} |
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__kfifo_poke_n(fifo, len, recsize); |
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ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied); |
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if (unlikely(ret)) { |
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*copied = 0; |
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return -EFAULT; |
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} |
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fifo->in += len + recsize; |
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return 0; |
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} |
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EXPORT_SYMBOL(__kfifo_from_user_r); |
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int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to, |
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unsigned long len, unsigned int *copied, size_t recsize) |
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{ |
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unsigned long ret; |
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unsigned int n; |
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if (fifo->in == fifo->out) { |
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*copied = 0; |
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return 0; |
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} |
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n = __kfifo_peek_n(fifo, recsize); |
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if (len > n) |
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len = n; |
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ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied); |
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if (unlikely(ret)) { |
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*copied = 0; |
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return -EFAULT; |
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} |
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fifo->out += n + recsize; |
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return 0; |
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} |
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EXPORT_SYMBOL(__kfifo_to_user_r); |
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unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo, |
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struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) |
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{ |
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BUG_ON(!nents); |
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len = __kfifo_max_r(len, recsize); |
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if (len + recsize > kfifo_unused(fifo)) |
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return 0; |
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return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize); |
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} |
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EXPORT_SYMBOL(__kfifo_dma_in_prepare_r); |
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void __kfifo_dma_in_finish_r(struct __kfifo *fifo, |
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unsigned int len, size_t recsize) |
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{ |
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len = __kfifo_max_r(len, recsize); |
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__kfifo_poke_n(fifo, len, recsize); |
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fifo->in += len + recsize; |
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} |
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EXPORT_SYMBOL(__kfifo_dma_in_finish_r); |
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unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo, |
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struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) |
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{ |
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BUG_ON(!nents); |
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len = __kfifo_max_r(len, recsize); |
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if (len + recsize > fifo->in - fifo->out) |
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return 0; |
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return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize); |
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} |
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EXPORT_SYMBOL(__kfifo_dma_out_prepare_r); |
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void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize) |
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{ |
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unsigned int len; |
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len = __kfifo_peek_n(fifo, recsize); |
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fifo->out += len + recsize; |
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} |
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EXPORT_SYMBOL(__kfifo_dma_out_finish_r);
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