1 files changed, 329 insertions, 81 deletions

diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 3765ff3c1bbe..35edbe22e9a9 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 +79,93 @@ 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, NULL, 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);
+        _kfifo_init(fifo, NULL, 0);
 }
 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 +174,272 @@ 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.
+ * @total: the actual returned data length.
+ *
+ * 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);
+