1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 72a4fcb17745..5e29e8031bbc 100644
@@ -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