This comment didn't quite keep up as extract_entropy() was split into
four functions. Put each bit by the function it describes.
Cc: "Theodore Ts'o" <ty...@mit.edu>
Signed-off-by: Greg Price <pr...@mit.edu>
---
drivers/char/random.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 04a117a..8ec4a9a 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -834,17 +834,9 @@ static void xfer_secondary_pool(struct entropy_store *r,
size_t nbytes)
}
/*
- * These functions extracts randomness from the "entropy pool", and
- * returns it in a buffer.
- *
- * The min parameter specifies the minimum amount we can pull before
- * failing to avoid races that defeat catastrophic reseeding while the
- * reserved parameter indicates how much entropy we must leave in the
- * pool after each pull to avoid starving other readers.
- *
- * Note: extract_entropy() assumes that .poolwords is a multiple of 16 words.
+ * This function decides how many bytes to actually take from the
+ * given pool, and also debits the entropy count accordingly.
*/
-
static size_t account(struct entropy_store *r, size_t nbytes, int min,
int reserved)
{
@@ -896,6 +888,12 @@ retry:
return nbytes;
}
+/*
+ * This function does the actual extraction for extract_entropy and
+ * extract_entropy_user.
+ *
+ * Note: we assume that .poolwords is a multiple of 16 words.
+ */
static void extract_buf(struct entropy_store *r, __u8 *out)
{
int i;
@@ -957,6 +955,15 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
memset(&hash, 0, sizeof(hash));
}
+/*
+ * This function extracts randomness from the "entropy pool", and
+ * returns it in a buffer.
+ *
+ * The min parameter specifies the minimum amount we can pull before
+ * failing to avoid races that defeat catastrophic reseeding while the
+ * reserved parameter indicates how much entropy we must leave in the
+ * pool after each pull to avoid starving other readers.
+ */
static ssize_t extract_entropy(struct entropy_store *r, void *buf,
size_t nbytes, int min, int reserved)
{
@@ -1007,6 +1014,10 @@ static ssize_t extract_entropy(struct entropy_store *r,
void *buf,
return ret;
}
+/*
+ * This function extracts randomness from the "entropy pool", and
+ * returns it in a userspace buffer.
+ */
static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf,
size_t nbytes)
{
--
1.8.3.2
--
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