---

yaml
---
r: 235079
b: refs/heads/master
c: 442a4ff
h: refs/heads/master
i:
  235077: 64680ca
  235075: c31ded3
  235071: b5b9cc9
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ce92136843cb6e14aba5fd7bc4e88dbe71e70c5a
+refs/heads/master: 442a4fffffa26fc3080350b4d50172f7589c3ac2

trunk/drivers/char/random.c

@@ -128,6 +128,7 @@
  * 	void add_input_randomness(unsigned int type, unsigned int code,
  *                                unsigned int value);
  * 	void add_interrupt_randomness(int irq);
+ * 	void add_disk_randomness(struct gendisk *disk);
  *
  * add_input_randomness() uses the input layer interrupt timing, as well as
  * the event type information from the hardware.
@@ -136,9 +137,15 @@
  * inputs to the entropy pool.  Note that not all interrupts are good
  * sources of randomness!  For example, the timer interrupts is not a
  * good choice, because the periodicity of the interrupts is too
- * regular, and hence predictable to an attacker.  Disk interrupts are
- * a better measure, since the timing of the disk interrupts are more
- * unpredictable.
+ * regular, and hence predictable to an attacker.  Network Interface
+ * Controller interrupts are a better measure, since the timing of the
+ * NIC interrupts are more unpredictable.
+ *
+ * add_disk_randomness() uses what amounts to the seek time of block
+ * layer request events, on a per-disk_devt basis, as input to the
+ * entropy pool. Note that high-speed solid state drives with very low
+ * seek times do not make for good sources of entropy, as their seek
+ * times are usually fairly consistent.
  *
  * All of these routines try to estimate how many bits of randomness a
  * particular randomness source.  They do this by keeping track of the