2 files changed, 24 insertions, 0 deletions

diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 86ad50a900c..7ad6d32dd67 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -113,6 +113,9 @@ extern unsigned int kfifo_in(struct kfifo *fifo,
                                 const void *from, unsigned int len);
 extern __must_check unsigned int kfifo_out(struct kfifo *fifo,
                                 void *to, unsigned int len);
+extern __must_check unsigned int kfifo_out_peek(struct kfifo *fifo,
+                                void *to, unsigned int len, unsigned offset);
+
 
 /**
  * kfifo_reset - removes the entire FIFO contents
diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index b50bb622e8b..7384f120be8 100644
--- a/kernel/kfifo.c
+++ b/kernel/kfifo.c
@@ -302,6 +302,27 @@ unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len)
 }
 EXPORT_SYMBOL(kfifo_out);
 
+/**
+ * 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);
+
+        __kfifo_out_data(fifo, to, len, offset);
+        return len;
+}
+EXPORT_SYMBOL(kfifo_out_peek);
+
 unsigned int __kfifo_out_generic(struct kfifo *fifo,
         void *to, unsigned int len, unsigned int recsize,
         unsigned int *total)