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From: Greg Price <price@MIT.EDU>
To: "Theodore Ts'o" <tytso@MIT.EDU>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 06/11] random: fix comment on "account"
Date: Thu, 7 Nov 2013 18:58:54 -0500	[thread overview]
Message-ID: <20131107235853.GI16018@ringworld.MIT.EDU> (raw)
In-Reply-To: <cover.1383868558.git.price@mit.edu>

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@mit.edu>
Signed-off-by: Greg Price <price@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


  parent reply	other threads:[~2013-11-08  0:04 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-07 23:57 [PATCH 00/11] random: code cleanups Greg Price
2013-11-07 23:57 ` [PATCH 01/11] random: fix typos / spelling errors in comments Greg Price
2013-11-07 23:58 ` [PATCH 02/11] random: fix comment on proc_do_uuid Greg Price
2013-11-07 23:58 ` [PATCH 03/11] random: fix description of get_random_bytes Greg Price
2013-11-07 23:58 ` [PATCH 04/11] random: simplify loop in random_read Greg Price
2013-11-07 23:58 ` [PATCH 05/11] random: declare trickle_count unsigned Greg Price
2013-11-07 23:58 ` Greg Price [this message]
2013-11-07 23:58 ` [PATCH 07/11] random: simplify accounting code slightly Greg Price
2013-11-07 23:59 ` [PATCH 08/11] random: simplify accounting logic Greg Price
2013-11-07 23:59 ` [PATCH 09/11] random: forget lock in lockless accounting Greg Price
2013-11-07 23:59 ` [PATCH 10/11] random: pull 'min' check in accounting to inside lockless update Greg Price
2013-11-07 23:59 ` [PATCH 11/11] random: simplify accounting code Greg Price
2013-11-12  4:24 ` [PATCH 00/11] random: code cleanups Theodore Ts'o
2013-11-12 22:40   ` Greg Price
2013-11-13  3:32     ` Theodore Ts'o
2013-11-13  4:02       ` H. Peter Anvin
2013-11-13  4:37         ` Greg Price
2013-11-13  4:51           ` H. Peter Anvin
2013-11-13  6:06             ` Greg Price
2013-11-13  4:23       ` Greg Price
2013-11-13  6:08         ` Theodore Ts'o
2013-11-13  6:28           ` Greg Price

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