linux-kernel - [PATCH 5/9] random: fix comment on "account"

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Date:	Wed, 13 Nov 2013 03:08:14 -0500
From:	Greg Price <price@....EDU>
To:	"Theodore Ts'o" <tytso@....edu>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH 5/9] random: fix comment on "account"

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" <tytso@....edu>
Signed-off-by: Greg Price <price@....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 cf1357b..fe7ecdd 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -962,17 +962,9 @@ static void push_to_pool(struct work_struct *work)
 }
 
 /*
- * 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)
 {
@@ -1022,6 +1014,12 @@ retry:
 	return ibytes;
 }
 
+/*
+ * 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;
@@ -1083,6 +1081,15 @@ 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)
 {
@@ -1133,6 +1140,10 @@ 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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