From: Greg Price <price@MIT.EDU>
To: "Theodore Ts'o" <tytso@MIT.EDU>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 5/9] random: fix comment on "account"
Date: Wed, 13 Nov 2013 03:08:14 -0500 [thread overview]
Message-ID: <20131113080814.GS16018@ringworld.MIT.EDU> (raw)
In-Reply-To: <cover.1384329436.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 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
next prev parent reply other threads:[~2013-11-13 8:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-13 8:07 [PATCH v2 0/9] random: code cleanups Greg Price
2013-11-13 8:07 ` [PATCH 1/9] random: fix typos / spelling errors in comments Greg Price
2013-11-29 19:56 ` Theodore Ts'o
2013-11-13 8:07 ` [PATCH 2/9] random: fix comment on proc_do_uuid Greg Price
2013-11-29 19:59 ` Theodore Ts'o
2013-11-13 8:07 ` [PATCH 3/9] random: fix description of get_random_bytes Greg Price
2013-11-29 20:00 ` Theodore Ts'o
2013-11-13 8:07 ` [PATCH 4/9] random: simplify loop in random_read Greg Price
2013-11-29 20:09 ` Theodore Ts'o
2013-11-30 5:30 ` Greg Price
2013-11-13 8:08 ` Greg Price [this message]
2013-11-29 20:53 ` [PATCH 5/9] random: fix comment on "account" Theodore Ts'o
2013-11-13 8:08 ` [PATCH 6/9] random: simplify accounting logic Greg Price
2013-11-30 1:04 ` Theodore Ts'o
2013-11-13 8:08 ` [PATCH 7/9] random: forget lock in lockless accounting Greg Price
2013-11-30 1:10 ` Theodore Ts'o
2013-11-13 8:08 ` [PATCH 8/9] random: tighten bound on random_read_wakeup_thresh Greg Price
2013-12-06 0:31 ` Theodore Ts'o
2013-11-13 8:08 ` [PATCH 9/9] random: simplify accounting code Greg Price
2013-12-06 1:13 ` Theodore Ts'o
2013-12-06 18:25 ` Greg Price
2013-12-07 14:48 ` Theodore Ts'o
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