minstrel: simplify and fix debugfs code

This patch cleans up the debugfs read function for the statistics by
using simple_read_from_buffer instead of its own semi-broken hack.
Also removes a useless member of the minstrel debugfs info struct.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 11 insertions, 29 deletions

diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
index 38bf4168fc3a..9372656f3f5e 100644
--- a/net/mac80211/rc80211_minstrel.h
+++ b/net/mac80211/rc80211_minstrel.h
@@ -80,6 +80,11 @@ struct minstrel_priv {
         unsigned int lookaround_rate_mrr;
 };
 
+struct minstrel_debugfs_info {
+        size_t len;
+        char buf[];
+};
+
 void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
 void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);
 
diff --git a/net/mac80211/rc80211_minstrel_debugfs.c b/net/mac80211/rc80211_minstrel_debugfs.c
index a715d9454f64..3e83402ece17 100644
--- a/net/mac80211/rc80211_minstrel_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_debugfs.c
@@ -52,21 +52,15 @@
 #include <net/mac80211.h>
 #include "rc80211_minstrel.h"
 
-struct minstrel_stats_info {
-        struct minstrel_sta_info *mi;
-        char buf[4096];
-        size_t len;
-};
-
 static int
 minstrel_stats_open(struct inode *inode, struct file *file)
 {
         struct minstrel_sta_info *mi = inode->i_private;
-        struct minstrel_stats_info *ms;
+        struct minstrel_debugfs_info *ms;
         unsigned int i, tp, prob, eprob;
         char *p;
 
-        ms = kmalloc(sizeof(*ms), GFP_KERNEL);
+        ms = kmalloc(sizeof(*ms) + 4096, GFP_KERNEL);
         if (!ms)
                 return -ENOMEM;
 
@@ -107,35 +101,18 @@ minstrel_stats_open(struct inode *inode, struct file *file)
 }
 
 static ssize_t
-minstrel_stats_read(struct file *file, char __user *buf, size_t len, loff_t *o)
+minstrel_stats_read(struct file *file, char __user *buf, size_t len, loff_t *ppos)
 {
-        struct minstrel_stats_info *ms;
-        char *src;
+        struct minstrel_debugfs_info *ms;
 
         ms = file->private_data;
-        src = ms->buf;
-
-        len = min(len, ms->len);
-        if (len <= *o)
-                return 0;
-
-        src += *o;
-        len -= *o;
-        *o += len;
-
-        if (copy_to_user(buf, src, len))
-                return -EFAULT;
-
-        return len;
+        return simple_read_from_buffer(buf, len, ppos, ms->buf, ms->len);
 }
 
 static int
 minstrel_stats_release(struct inode *inode, struct file *file)
 {
-        struct minstrel_stats_info *ms = file->private_data;
-
-        kfree(ms);
-
+        kfree(file->private_data);
         return 0;
 }