X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fkfifo.c;h=5d1d907378a299ad6c6aab16b15d55d1248f296e;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=2fbe06a4a6eb83e8d0b17d1363236c1030ad92e0;hpb=87fc8d1bb10cd459024a742c6a10961fefcef18f;p=linux-2.6.git

diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 2fbe06a4a..5d1d90737 100644
--- a/kernel/kfifo.c
+++ b/kernel/kfifo.c
@@ -25,7 +25,7 @@
 #include <linux/err.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.
@@ -36,7 +36,7 @@
  * struct kfifo with kfree().
  */
 struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size,
-			 int gfp_mask, spinlock_t *lock)
+			 gfp_t gfp_mask, spinlock_t *lock)
 {
 	struct kfifo *fifo;
 
@@ -56,7 +56,7 @@ struct kfifo *kfifo_init(unsigned char *buffer, unsigned int 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.
  * @gfp_mask: get_free_pages mask, passed to kmalloc()
@@ -64,7 +64,7 @@ EXPORT_SYMBOL(kfifo_init);
  *
  * The size will be rounded-up to a power of 2.
  */
-struct kfifo *kfifo_alloc(unsigned int size, int gfp_mask, spinlock_t *lock)
+struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock)
 {
 	unsigned char *buffer;
 	struct kfifo *ret;
@@ -91,7 +91,7 @@ struct kfifo *kfifo_alloc(unsigned int size, int gfp_mask, spinlock_t *lock)
 }
 EXPORT_SYMBOL(kfifo_alloc);
 
-/*
+/**
  * kfifo_free - frees the FIFO
  * @fifo: the fifo to be freed.
  */
@@ -102,7 +102,7 @@ void kfifo_free(struct kfifo *fifo)
 }
 EXPORT_SYMBOL(kfifo_free);
 
-/*
+/**
  * __kfifo_put - puts some data into the FIFO, no locking version
  * @fifo: the fifo to be used.
  * @buffer: the data to be added.
@@ -122,6 +122,13 @@ unsigned int __kfifo_put(struct kfifo *fifo,
 
 	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();
+
 	/* 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);
@@ -129,13 +136,20 @@ unsigned int __kfifo_put(struct kfifo *fifo,
 	/* then put the rest (if any) at the beginning of the buffer */
 	memcpy(fifo->buffer, buffer + l, len - l);
 
+	/*
+	 * Ensure that we add the bytes to the kfifo -before-
+	 * we update the fifo->in index.
+	 */
+
+	smp_wmb();
+
 	fifo->in += len;
 
 	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.
@@ -154,6 +168,13 @@ unsigned int __kfifo_get(struct kfifo *fifo,
 
 	len = min(len, fifo->in - fifo->out);
 
+	/*
+	 * Ensure that we sample the fifo->in index -before- we
+	 * start removing bytes from the kfifo.
+	 */
+
+	smp_rmb();
+
 	/* 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);
@@ -161,6 +182,13 @@ unsigned int __kfifo_get(struct kfifo *fifo,
 	/* then get the rest (if any) from the beginning of the buffer */
 	memcpy(buffer + l, fifo->buffer, len - l);
 
+	/*
+	 * Ensure that we remove the bytes from the kfifo -before-
+	 * we update the fifo->out index.
+	 */
+
+	smp_mb();
+
 	fifo->out += len;
 
 	return len;