Re: [PATCH v2] rc80211_pid: Fix fast_start parameter handling

[Mattias Nissler <mattias.nissler@gmx.de>]

This removes the fast_start parameter from the rc_pid parameters information
and instead uses the parameter macro when initializing the rc_pid state. Since
the parameter is only used on initialization, there is no point of making
exporting it via debugfs. This also fixes uninitialized memory references to
the fast_start and norm_offset parameters detected by the kmemcheck utility.
Thanks to Vegard Nossum for reporting the bug.

Signed-off-by: Mattias Nissler <mattias.nissler@gmx.de>
---

Updated patch description. Any more comments? Stefano? John?

Mattias


 net/mac80211/rc80211_pid.h      |    5 -----
 net/mac80211/rc80211_pid_algo.c |   31 +++++++++++++------------------
 2 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/net/mac80211/rc80211_pid.h b/net/mac80211/rc80211_pid.h
index 04afc13..4ea7b97 100644
--- a/net/mac80211/rc80211_pid.h
+++ b/net/mac80211/rc80211_pid.h
@@ -141,7 +141,6 @@ struct rc_pid_events_file_info {
  *	rate behaviour values (lower means we should trust more what we learnt
  *	about behaviour of rates, higher means we should trust more the natural
  *	ordering of rates)
- * @fast_start: if Y, push high rates right after initialization
  */
 struct rc_pid_debugfs_entries {
 	struct dentry *dir;
@@ -154,7 +153,6 @@ struct rc_pid_debugfs_entries {
 	struct dentry *sharpen_factor;
 	struct dentry *sharpen_duration;
 	struct dentry *norm_offset;
-	struct dentry *fast_start;
 };
 
 void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf,
@@ -267,9 +265,6 @@ struct rc_pid_info {
 	/* Normalization offset. */
 	unsigned int norm_offset;
 
-	/* Fast starst parameter. */
-	unsigned int fast_start;
-
 	/* Rates information. */
 	struct rc_pid_rateinfo *rinfo;
 
diff --git a/net/mac80211/rc80211_pid_algo.c b/net/mac80211/rc80211_pid_algo.c
index a849b74..bcd27c1 100644
--- a/net/mac80211/rc80211_pid_algo.c
+++ b/net/mac80211/rc80211_pid_algo.c
@@ -398,13 +398,25 @@ static void *rate_control_pid_alloc(struct ieee80211_local *local)
 		return NULL;
 	}
 
+	pinfo->target = RC_PID_TARGET_PF;
+	pinfo->sampling_period = RC_PID_INTERVAL;
+	pinfo->coeff_p = RC_PID_COEFF_P;
+	pinfo->coeff_i = RC_PID_COEFF_I;
+	pinfo->coeff_d = RC_PID_COEFF_D;
+	pinfo->smoothing_shift = RC_PID_SMOOTHING_SHIFT;
+	pinfo->sharpen_factor = RC_PID_SHARPENING_FACTOR;
+	pinfo->sharpen_duration = RC_PID_SHARPENING_DURATION;
+	pinfo->norm_offset = RC_PID_NORM_OFFSET;
+	pinfo->rinfo = rinfo;
+	pinfo->oldrate = 0;
+
 	/* Sort the rates. This is optimized for the most common case (i.e.
 	 * almost-sorted CCK+OFDM rates). Kind of bubble-sort with reversed
 	 * mapping too. */
 	for (i = 0; i < sband->n_bitrates; i++) {
 		rinfo[i].index = i;
 		rinfo[i].rev_index = i;
-		if (pinfo->fast_start)
+		if (RC_PID_FAST_START)
 			rinfo[i].diff = 0;
 		else
 			rinfo[i].diff = i * pinfo->norm_offset;
@@ -425,19 +437,6 @@ static void *rate_control_pid_alloc(struct ieee80211_local *local)
 			break;
 	}
 
-	pinfo->target = RC_PID_TARGET_PF;
-	pinfo->sampling_period = RC_PID_INTERVAL;
-	pinfo->coeff_p = RC_PID_COEFF_P;
-	pinfo->coeff_i = RC_PID_COEFF_I;
-	pinfo->coeff_d = RC_PID_COEFF_D;
-	pinfo->smoothing_shift = RC_PID_SMOOTHING_SHIFT;
-	pinfo->sharpen_factor = RC_PID_SHARPENING_FACTOR;
-	pinfo->sharpen_duration = RC_PID_SHARPENING_DURATION;
-	pinfo->norm_offset = RC_PID_NORM_OFFSET;
-	pinfo->fast_start = RC_PID_FAST_START;
-	pinfo->rinfo = rinfo;
-	pinfo->oldrate = 0;
-
 #ifdef CONFIG_MAC80211_DEBUGFS
 	de = &pinfo->dentries;
 	de->dir = debugfs_create_dir("rc80211_pid",
@@ -465,9 +464,6 @@ static void *rate_control_pid_alloc(struct ieee80211_local *local)
 	de->norm_offset = debugfs_create_u32("norm_offset",
 					     S_IRUSR | S_IWUSR, de->dir,
 					     &pinfo->norm_offset);
-	de->fast_start = debugfs_create_bool("fast_start",
-					     S_IRUSR | S_IWUSR, de->dir,
-					     &pinfo->fast_start);
 #endif
 
 	return pinfo;
@@ -479,7 +475,6 @@ static void rate_control_pid_free(void *priv)
 #ifdef CONFIG_MAC80211_DEBUGFS
 	struct rc_pid_debugfs_entries *de = &pinfo->dentries;
 
-	debugfs_remove(de->fast_start);
 	debugfs_remove(de->norm_offset);
 	debugfs_remove(de->sharpen_duration);
 	debugfs_remove(de->sharpen_factor);
-- 
1.5.6.1