1 files changed, 25 insertions, 19 deletions

diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 3d44e9c65a8e..6f6c5f300af6 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -67,7 +67,7 @@ struct kfifo {
 /**
  * DECLARE_KFIFO - macro to declare a kfifo and the associated buffer
  * @name: name of the declared kfifo datatype
- * @size: size of the fifo buffer
+ * @size: size of the fifo buffer. Must be a power of two.
  *
  * Note1: the macro can be used inside struct or union declaration
  * Note2: the macro creates two objects:
@@ -81,7 +81,7 @@ union { \
 }
 
 /**
- * INIT_KFIFO - Initialize a kfifo declared by DECLARED_KFIFO
+ * INIT_KFIFO - Initialize a kfifo declared by DECLARE_KFIFO
  * @name: name of the declared kfifo datatype
  */
 #define INIT_KFIFO(name) \
@@ -91,7 +91,7 @@ union { \
 /**
  * DEFINE_KFIFO - macro to define and initialize a kfifo
  * @name: name of the declared kfifo datatype
- * @size: size of the fifo buffer
+ * @size: size of the fifo buffer. Must be a power of two.
  *
  * Note1: the macro can be used for global and local kfifo data type variables
  * Note2: the macro creates two objects:
@@ -104,15 +104,28 @@ union { \
 
 #undef __kfifo_initializer
 
-extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer,
+extern void kfifo_init(struct kfifo *fifo, void *buffer,
                         unsigned int size);
 extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size,
                         gfp_t gfp_mask);
 extern void kfifo_free(struct kfifo *fifo);
 extern unsigned int kfifo_in(struct kfifo *fifo,
-                                const unsigned char *from, unsigned int len);
+                                const void *from, unsigned int len);
 extern __must_check unsigned int kfifo_out(struct kfifo *fifo,
-                                unsigned char *to, unsigned int len);
+                                void *to, unsigned int len);
+extern __must_check unsigned int kfifo_out_peek(struct kfifo *fifo,
+                                void *to, unsigned int len, unsigned offset);
+
+/**
+ * kfifo_initialized - Check if kfifo is initialized.
+ * @fifo: fifo to check
+ * Return %true if FIFO is initialized, otherwise %false.
+ * Assumes the fifo was 0 before.
+ */
+static inline bool kfifo_initialized(struct kfifo *fifo)
+{
+        return fifo->buffer != 0;
+}
 
 /**
  * kfifo_reset - removes the entire FIFO contents
@@ -194,7 +207,7 @@ static inline __must_check unsigned int kfifo_avail(struct kfifo *fifo)
  * bytes copied.
  */
 static inline unsigned int kfifo_in_locked(struct kfifo *fifo,
-                const unsigned char *from, unsigned int n, spinlock_t *lock)
+                const void *from, unsigned int n, spinlock_t *lock)
 {
         unsigned long flags;
         unsigned int ret;
@@ -219,7 +232,7 @@ static inline unsigned int kfifo_in_locked(struct kfifo *fifo,
  * @to buffer and returns the number of copied bytes.
  */
 static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo,
-        unsigned char *to, unsigned int n, spinlock_t *lock)
+        void *to, unsigned int n, spinlock_t *lock)
 {
         unsigned long flags;
         unsigned int ret;
@@ -228,13 +241,6 @@ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo,
 
         ret = kfifo_out(fifo, to, n);
 
-        /*
-         * optimization: if the FIFO is empty, set the indices to 0
-         * so we don't wrap the next time
-         */
-        if (kfifo_is_empty(fifo))
-                kfifo_reset(fifo);
-
         spin_unlock_irqrestore(lock, flags);
 
         return ret;
@@ -242,11 +248,11 @@ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo,
 
 extern void kfifo_skip(struct kfifo *fifo, unsigned int len);
 
-extern __must_check unsigned int kfifo_from_user(struct kfifo *fifo,
-        const void __user *from, unsigned int n);
+extern __must_check int kfifo_from_user(struct kfifo *fifo,
+        const void __user *from, unsigned int n, unsigned *lenout);
 
-extern __must_check unsigned int kfifo_to_user(struct kfifo *fifo,
-        void __user *to, unsigned int n);
+extern __must_check int kfifo_to_user(struct kfifo *fifo,
+        void __user *to, unsigned int n, unsigned *lenout);
 
 /*
  * __kfifo_add_out internal helper function for updating the out offset