/*
- * A simple kernel FIFO implementation.
+ * A generic kernel FIFO implementation
*
- * Copyright (C) 2004 Stelian Pop <stelian@popies.net>
+ * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
*
* 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
+ * 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
*/
#include <linux/kernel.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/slab.h>
#include <linux/err.h>
-#include <linux/kfifo.h>
#include <linux/log2.h>
+#include <linux/uaccess.h>
+#include <linux/kfifo.h>
-/**
- * kfifo_init - allocates a new FIFO using a preallocated 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
- *
- * Do NOT pass the kfifo to kfifo_free() after use! Simply free the
- * &struct kfifo with kfree().
+/*
+ * internal helper to calculate the unused elements in a fifo
*/
-struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size,
- gfp_t gfp_mask, spinlock_t *lock)
+static inline unsigned int kfifo_unused(struct __kfifo *fifo)
+{
+ return (fifo->mask + 1) - (fifo->in - fifo->out);
+}
+
+int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
+ size_t esize, gfp_t gfp_mask)
{
- struct kfifo *fifo;
+ /*
+ * round down to the next power of 2, since our 'let the indices
+ * wrap' technique works only in this case.
+ */
+ if (!is_power_of_2(size))
+ size = rounddown_pow_of_two(size);
- /* size must be a power of 2 */
- BUG_ON(!is_power_of_2(size));
+ fifo->in = 0;
+ fifo->out = 0;
+ fifo->esize = esize;
- fifo = kmalloc(sizeof(struct kfifo), gfp_mask);
- if (!fifo)
- return ERR_PTR(-ENOMEM);
+ if (size < 2) {
+ fifo->data = NULL;
+ fifo->mask = 0;
+ return -EINVAL;
+ }
+
+ fifo->data = kmalloc(size * esize, gfp_mask);
- fifo->buffer = buffer;
- fifo->size = size;
- fifo->in = fifo->out = 0;
- fifo->lock = lock;
+ if (!fifo->data) {
+ fifo->mask = 0;
+ return -ENOMEM;
+ }
+ fifo->mask = size - 1;
- return fifo;
+ return 0;
}
-EXPORT_SYMBOL(kfifo_init);
+EXPORT_SYMBOL(__kfifo_alloc);
-/**
- * kfifo_alloc - allocates a new FIFO and its internal buffer
- * @size: the size of the internal buffer to be allocated.
- * @gfp_mask: get_free_pages mask, passed to kmalloc()
- * @lock: the lock to be used to protect the fifo buffer
- *
- * The size will be rounded-up to a power of 2.
- */
-struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock)
+void __kfifo_free(struct __kfifo *fifo)
{
- unsigned char *buffer;
- struct kfifo *ret;
+ kfree(fifo->data);
+ fifo->in = 0;
+ fifo->out = 0;
+ fifo->esize = 0;
+ fifo->data = NULL;
+ fifo->mask = 0;
+}
+EXPORT_SYMBOL(__kfifo_free);
- /*
- * round up to the next power of 2, since our 'let the indices
- * wrap' tachnique works only in this case.
- */
- if (size & (size - 1)) {
- BUG_ON(size > 0x80000000);
- size = roundup_pow_of_two(size);
+int __kfifo_init(struct __kfifo *fifo, void *buffer,
+ unsigned int size, size_t esize)
+{
+ size /= esize;
+
+ if (!is_power_of_2(size))
+ size = rounddown_pow_of_two(size);
+
+ fifo->in = 0;
+ fifo->out = 0;
+ fifo->esize = esize;
+ fifo->data = buffer;
+
+ if (size < 2) {
+ fifo->mask = 0;
+ return -EINVAL;
}
+ fifo->mask = size - 1;
- buffer = kmalloc(size, gfp_mask);
- if (!buffer)
- return ERR_PTR(-ENOMEM);
+ return 0;
+}
+EXPORT_SYMBOL(__kfifo_init);
- ret = kfifo_init(buffer, size, gfp_mask, lock);
+static void kfifo_copy_in(struct __kfifo *fifo, const void *src,
+ unsigned int len, unsigned int off)
+{
+ unsigned int size = fifo->mask + 1;
+ unsigned int esize = fifo->esize;
+ unsigned int l;
- if (IS_ERR(ret))
- kfree(buffer);
+ off &= fifo->mask;
+ if (esize != 1) {
+ off *= esize;
+ size *= esize;
+ len *= esize;
+ }
+ l = min(len, size - off);
- return ret;
+ memcpy(fifo->data + off, src, l);
+ memcpy(fifo->data, src + l, len - l);
+ /*
+ * make sure that the data in the fifo is up to date before
+ * incrementing the fifo->in index counter
+ */
+ smp_wmb();
}
-EXPORT_SYMBOL(kfifo_alloc);
-/**
- * kfifo_free - frees the FIFO
- * @fifo: the fifo to be freed.
- */
-void kfifo_free(struct kfifo *fifo)
+unsigned int __kfifo_in(struct __kfifo *fifo,
+ const void *buf, unsigned int len)
{
- kfree(fifo->buffer);
- kfree(fifo);
+ unsigned int l;
+
+ l = kfifo_unused(fifo);
+ if (len > l)
+ len = l;
+
+ kfifo_copy_in(fifo, buf, len, fifo->in);
+ fifo->in += len;
+ return len;
}
-EXPORT_SYMBOL(kfifo_free);
+EXPORT_SYMBOL(__kfifo_in);
-/**
- * __kfifo_put - puts some data into the FIFO, no locking version
- * @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.
- */
-unsigned int __kfifo_put(struct kfifo *fifo,
- unsigned char *buffer, unsigned int len)
+static void kfifo_copy_out(struct __kfifo *fifo, void *dst,
+ unsigned int len, unsigned int off)
{
+ unsigned int size = fifo->mask + 1;
+ unsigned int esize = fifo->esize;
unsigned int l;
- len = min(len, fifo->size - fifo->in + fifo->out);
+ off &= fifo->mask;
+ if (esize != 1) {
+ off *= esize;
+ size *= esize;
+ len *= esize;
+ }
+ l = min(len, size - off);
+ memcpy(dst, fifo->data + off, l);
+ memcpy(dst + l, fifo->data, len - l);
/*
- * Ensure that we sample the fifo->out index -before- we
- * start putting bytes into the kfifo.
+ * make sure that the data is copied before
+ * incrementing the fifo->out index counter
*/
+ smp_wmb();
+}
- smp_mb();
+unsigned int __kfifo_out_peek(struct __kfifo *fifo,
+ void *buf, unsigned int len)
+{
+ unsigned int l;
- /* 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 = fifo->in - fifo->out;
+ if (len > l)
+ len = l;
- /* then put the rest (if any) at the beginning of the buffer */
- memcpy(fifo->buffer, buffer + l, len - l);
+ kfifo_copy_out(fifo, buf, len, fifo->out);
+ return len;
+}
+EXPORT_SYMBOL(__kfifo_out_peek);
+unsigned int __kfifo_out(struct __kfifo *fifo,
+ void *buf, unsigned int len)
+{
+ len = __kfifo_out_peek(fifo, buf, len);
+ fifo->out += len;
+ return len;
+}
+EXPORT_SYMBOL(__kfifo_out);
+
+static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,
+ const void __user *from, unsigned int len, unsigned int off,
+ unsigned int *copied)
+{
+ unsigned int size = fifo->mask + 1;
+ unsigned int esize = fifo->esize;
+ unsigned int l;
+ unsigned long ret;
+
+ off &= fifo->mask;
+ if (esize != 1) {
+ off *= esize;
+ size *= esize;
+ len *= esize;
+ }
+ l = min(len, size - off);
+
+ ret = copy_from_user(fifo->data + off, from, l);
+ if (unlikely(ret))
+ ret = DIV_ROUND_UP(ret + len - l, esize);
+ else {
+ ret = copy_from_user(fifo->data, from + l, len - l);
+ if (unlikely(ret))
+ ret = DIV_ROUND_UP(ret, esize);
+ }
/*
- * Ensure that we add the bytes to the kfifo -before-
- * we update the fifo->in index.
+ * make sure that the data in the fifo is up to date before
+ * incrementing the fifo->in index counter
*/
-
smp_wmb();
+ *copied = len - ret;
+ /* return the number of elements which are not copied */
+ return ret;
+}
+int __kfifo_from_user(struct __kfifo *fifo, const void __user *from,
+ unsigned long len, unsigned int *copied)
+{
+ unsigned int l;
+ unsigned long ret;
+ unsigned int esize = fifo->esize;
+ int err;
+
+ if (esize != 1)
+ len /= esize;
+
+ l = kfifo_unused(fifo);
+ if (len > l)
+ len = l;
+
+ ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);
+ if (unlikely(ret)) {
+ len -= ret;
+ err = -EFAULT;
+ } else
+ err = 0;
fifo->in += len;
+ return err;
+}
+EXPORT_SYMBOL(__kfifo_from_user);
+
+static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to,
+ unsigned int len, unsigned int off, unsigned int *copied)
+{
+ unsigned int l;
+ unsigned long ret;
+ unsigned int size = fifo->mask + 1;
+ unsigned int esize = fifo->esize;
+
+ off &= fifo->mask;
+ if (esize != 1) {
+ off *= esize;
+ size *= esize;
+ len *= esize;
+ }
+ l = min(len, size - off);
+
+ ret = copy_to_user(to, fifo->data + off, l);
+ if (unlikely(ret))
+ ret = DIV_ROUND_UP(ret + len - l, esize);
+ else {
+ ret = copy_to_user(to + l, fifo->data, len - l);
+ if (unlikely(ret))
+ ret = DIV_ROUND_UP(ret, esize);
+ }
+ /*
+ * make sure that the data is copied before
+ * incrementing the fifo->out index counter
+ */
+ smp_wmb();
+ *copied = len - ret;
+ /* return the number of elements which are not copied */
+ return ret;
+}
+
+int __kfifo_to_user(struct __kfifo *fifo, void __user *to,
+ unsigned long len, unsigned int *copied)
+{
+ unsigned int l;
+ unsigned long ret;
+ unsigned int esize = fifo->esize;
+ int err;
+
+ if (esize != 1)
+ len /= esize;
+
+ l = fifo->in - fifo->out;
+ if (len > l)
+ len = l;
+ ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);
+ if (unlikely(ret)) {
+ len -= ret;
+ err = -EFAULT;
+ } else
+ err = 0;
+ fifo->out += len;
+ return err;
+}
+EXPORT_SYMBOL(__kfifo_to_user);
+
+static int setup_sgl_buf(struct scatterlist *sgl, void *buf,
+ int nents, unsigned int len)
+{
+ int n;
+ unsigned int l;
+ unsigned int off;
+ struct page *page;
+
+ if (!nents)
+ return 0;
+
+ if (!len)
+ return 0;
+
+ n = 0;
+ page = virt_to_page(buf);
+ off = offset_in_page(buf);
+ l = 0;
+
+ while (len >= l + PAGE_SIZE - off) {
+ struct page *npage;
+
+ l += PAGE_SIZE;
+ buf += PAGE_SIZE;
+ npage = virt_to_page(buf);
+ if (page_to_phys(page) != page_to_phys(npage) - l) {
+ sg_set_page(sgl, page, l - off, off);
+ sgl = sg_next(sgl);
+ if (++n == nents || sgl == NULL)
+ return n;
+ page = npage;
+ len -= l - off;
+ l = off = 0;
+ }
+ }
+ sg_set_page(sgl, page, len, off);
+ return n + 1;
+}
+
+static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
+ int nents, unsigned int len, unsigned int off)
+{
+ unsigned int size = fifo->mask + 1;
+ unsigned int esize = fifo->esize;
+ unsigned int l;
+ unsigned int n;
+
+ off &= fifo->mask;
+ if (esize != 1) {
+ off *= esize;
+ size *= esize;
+ len *= esize;
+ }
+ l = min(len, size - off);
+
+ n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
+ n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
+
+ return n;
+}
+unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
+ struct scatterlist *sgl, int nents, unsigned int len)
+{
+ unsigned int l;
+
+ l = kfifo_unused(fifo);
+ if (len > l)
+ len = l;
+
+ return setup_sgl(fifo, sgl, nents, len, fifo->in);
+}
+EXPORT_SYMBOL(__kfifo_dma_in_prepare);
+
+unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
+ struct scatterlist *sgl, int nents, unsigned int len)
+{
+ unsigned int l;
+
+ l = fifo->in - fifo->out;
+ if (len > l)
+ len = l;
+
+ return setup_sgl(fifo, sgl, nents, len, fifo->out);
+}
+EXPORT_SYMBOL(__kfifo_dma_out_prepare);
+
+unsigned int __kfifo_max_r(unsigned int len, size_t recsize)
+{
+ unsigned int max = (1 << (recsize << 3)) - 1;
+
+ if (len > max)
+ return max;
return len;
}
-EXPORT_SYMBOL(__kfifo_put);
-/**
- * __kfifo_get - gets some data from the FIFO, no locking version
- * @fifo: the fifo to be used.
- * @buffer: 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.
- *
- * Note that with only one concurrent reader and one concurrent
- * writer, you don't need extra locking to use these functions.
+#define __KFIFO_PEEK(data, out, mask) \
+ ((data)[(out) & (mask)])
+/*
+ * __kfifo_peek_n internal helper function for determinate the length of
+ * the next record in the fifo
*/
-unsigned int __kfifo_get(struct kfifo *fifo,
- unsigned char *buffer, unsigned int len)
+static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize)
{
unsigned int l;
+ unsigned int mask = fifo->mask;
+ unsigned char *data = fifo->data;
- len = min(len, fifo->in - fifo->out);
+ l = __KFIFO_PEEK(data, fifo->out, mask);
- /*
- * Ensure that we sample the fifo->in index -before- we
- * start removing bytes from the kfifo.
- */
+ if (--recsize)
+ l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;
- smp_rmb();
+ return l;
+}
- /* 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);
+#define __KFIFO_POKE(data, in, mask, val) \
+ ( \
+ (data)[(in) & (mask)] = (unsigned char)(val) \
+ )
- /* then get the rest (if any) from the beginning of the buffer */
- memcpy(buffer + l, fifo->buffer, len - l);
+/*
+ * __kfifo_poke_n internal helper function for storeing the length of
+ * the record into the fifo
+ */
+static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize)
+{
+ unsigned int mask = fifo->mask;
+ unsigned char *data = fifo->data;
- /*
- * Ensure that we remove the bytes from the kfifo -before-
- * we update the fifo->out index.
- */
+ __KFIFO_POKE(data, fifo->in, mask, n);
- smp_mb();
+ if (recsize > 1)
+ __KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);
+}
- fifo->out += len;
+unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize)
+{
+ return __kfifo_peek_n(fifo, recsize);
+}
+EXPORT_SYMBOL(__kfifo_len_r);
+
+unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf,
+ unsigned int len, size_t recsize)
+{
+ if (len + recsize > kfifo_unused(fifo))
+ return 0;
+
+ __kfifo_poke_n(fifo, len, recsize);
+
+ kfifo_copy_in(fifo, buf, len, fifo->in + recsize);
+ fifo->in += len + recsize;
+ return len;
+}
+EXPORT_SYMBOL(__kfifo_in_r);
+
+static unsigned int kfifo_out_copy_r(struct __kfifo *fifo,
+ void *buf, unsigned int len, size_t recsize, unsigned int *n)
+{
+ *n = __kfifo_peek_n(fifo, recsize);
+ if (len > *n)
+ len = *n;
+
+ kfifo_copy_out(fifo, buf, len, fifo->out + recsize);
return len;
}
-EXPORT_SYMBOL(__kfifo_get);
+
+unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,
+ unsigned int len, size_t recsize)
+{
+ unsigned int n;
+
+ if (fifo->in == fifo->out)
+ return 0;
+
+ return kfifo_out_copy_r(fifo, buf, len, recsize, &n);
+}
+EXPORT_SYMBOL(__kfifo_out_peek_r);
+
+unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
+ unsigned int len, size_t recsize)
+{
+ unsigned int n;
+
+ if (fifo->in == fifo->out)
+ return 0;
+
+ len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);
+ fifo->out += n + recsize;
+ return len;
+}
+EXPORT_SYMBOL(__kfifo_out_r);
+
+void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)
+{
+ unsigned int n;
+
+ n = __kfifo_peek_n(fifo, recsize);
+ fifo->out += n + recsize;
+}
+EXPORT_SYMBOL(__kfifo_skip_r);
+
+int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,
+ unsigned long len, unsigned int *copied, size_t recsize)
+{
+ unsigned long ret;
+
+ len = __kfifo_max_r(len, recsize);
+
+ if (len + recsize > kfifo_unused(fifo)) {
+ *copied = 0;
+ return 0;
+ }
+
+ __kfifo_poke_n(fifo, len, recsize);
+
+ ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);
+ if (unlikely(ret)) {
+ *copied = 0;
+ return -EFAULT;
+ }
+ fifo->in += len + recsize;
+ return 0;
+}
+EXPORT_SYMBOL(__kfifo_from_user_r);
+
+int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
+ unsigned long len, unsigned int *copied, size_t recsize)
+{
+ unsigned long ret;
+ unsigned int n;
+
+ if (fifo->in == fifo->out) {
+ *copied = 0;
+ return 0;
+ }
+
+ n = __kfifo_peek_n(fifo, recsize);
+ if (len > n)
+ len = n;
+
+ ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);
+ if (unlikely(ret)) {
+ *copied = 0;
+ return -EFAULT;
+ }
+ fifo->out += n + recsize;
+ return 0;
+}
+EXPORT_SYMBOL(__kfifo_to_user_r);
+
+unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
+ struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
+{
+ if (!nents)
+ BUG();
+
+ len = __kfifo_max_r(len, recsize);
+
+ if (len + recsize > kfifo_unused(fifo))
+ return 0;
+
+ return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
+}
+EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);
+
+void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
+ unsigned int len, size_t recsize)
+{
+ len = __kfifo_max_r(len, recsize);
+ __kfifo_poke_n(fifo, len, recsize);
+ fifo->in += len + recsize;
+}
+EXPORT_SYMBOL(__kfifo_dma_in_finish_r);
+
+unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
+ struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
+{
+ if (!nents)
+ BUG();
+
+ len = __kfifo_max_r(len, recsize);
+
+ if (len + recsize > fifo->in - fifo->out)
+ return 0;
+
+ return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
+}
+EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);
+
+void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize)
+{
+ unsigned int len;
+
+ len = __kfifo_peek_n(fifo, recsize);
+ fifo->out += len + recsize;
+}
+EXPORT_SYMBOL(__kfifo_dma_out_finish_r);
projects / linux-flexiantxendom0-3.2.10.git / blobdiff