rc80211-pid: add debugging

This adds a new debugfs file from which rate control relevant events can be
read one event per line. The output includes the current time, so graphs can be
created showing the rate control parameters. This helps in evaluating and
tuning rate control parameters. While at it, we split headers and code for
better readability.

Signed-off-by: Mattias Nissler <mattias.nissler@gmx.de>
Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 223 insertions, 0 deletions

diff --git a/net/mac80211/rc80211_pid_debugfs.c b/net/mac80211/rc80211_pid_debugfs.c
new file mode 100644
index 000000000000..91818e4ff002
--- /dev/null
+++ b/net/mac80211/rc80211_pid_debugfs.c
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2007, Mattias Nissler <mattias.nissler@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/poll.h>
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+
+#include <net/mac80211.h>
+#include "ieee80211_rate.h"
+
+#include "rc80211_pid.h"
+
+static void rate_control_pid_event(struct rc_pid_event_buffer *buf,
+                                   enum rc_pid_event_type type,
+                                   union rc_pid_event_data *data)
+{
+        struct rc_pid_event *ev;
+        unsigned long status;
+
+        spin_lock_irqsave(&buf->lock, status);
+        ev = &(buf->ring[buf->next_entry]);
+        buf->next_entry = (buf->next_entry + 1) % RC_PID_EVENT_RING_SIZE;
+
+        ev->timestamp = jiffies;
+        ev->id = buf->ev_count++;
+        ev->type = type;
+        ev->data = *data;
+
+        spin_unlock_irqrestore(&buf->lock, status);
+
+        wake_up_all(&buf->waitqueue);
+}
+
+void rate_control_pid_event_tx_status(struct rc_pid_event_buffer *buf,
+                                             struct ieee80211_tx_status *stat)
+{
+        union rc_pid_event_data evd;
+
+        memcpy(&evd.tx_status, stat, sizeof(struct ieee80211_tx_status));
+        rate_control_pid_event(buf, RC_PID_EVENT_TYPE_TX_STATUS, &evd);
+}
+
+void rate_control_pid_event_rate_change(struct rc_pid_event_buffer *buf,
+                                               int index, int rate)
+{
+        union rc_pid_event_data evd;
+
+        evd.index = index;
+        evd.rate = rate;
+        rate_control_pid_event(buf, RC_PID_EVENT_TYPE_RATE_CHANGE, &evd);
+}
+
+void rate_control_pid_event_tx_rate(struct rc_pid_event_buffer *buf,
+                                           int index, int rate)
+{
+        union rc_pid_event_data evd;
+
+        evd.index = index;
+        evd.rate = rate;
+        rate_control_pid_event(buf, RC_PID_EVENT_TYPE_TX_RATE, &evd);
+}
+
+void rate_control_pid_event_pf_sample(struct rc_pid_event_buffer *buf,
+                                             s32 pf_sample, s32 prop_err,
+                                             s32 int_err, s32 der_err)
+{
+        union rc_pid_event_data evd;
+
+        evd.pf_sample = pf_sample;
+        evd.prop_err = prop_err;
+        evd.int_err = int_err;
+        evd.der_err = der_err;
+        rate_control_pid_event(buf, RC_PID_EVENT_TYPE_PF_SAMPLE, &evd);
+}
+
+static int rate_control_pid_events_open(struct inode *inode, struct file *file)
+{
+        struct rc_pid_sta_info *sinfo = inode->i_private;
+        struct rc_pid_event_buffer *events = &sinfo->events;
+        struct rc_pid_events_file_info *file_info;
+        unsigned int status;
+
+        /* Allocate a state struct */
+        file_info = kmalloc(sizeof(*file_info), GFP_KERNEL);
+        if (file_info == NULL)
+                return -ENOMEM;
+
+        spin_lock_irqsave(&events->lock, status);
+
+        file_info->next_entry = events->next_entry;
+        file_info->events = events;
+
+        spin_unlock_irqrestore(&events->lock, status);
+
+        file->private_data = file_info;
+
+        return 0;
+}
+
+static int rate_control_pid_events_release(struct inode *inode,
+                                           struct file *file)
+{
+        struct rc_pid_events_file_info *file_info = file->private_data;
+
+        kfree(file_info);
+
+        return 0;
+}
+
+static unsigned int rate_control_pid_events_poll(struct file *file,
+                                                 poll_table *wait)
+{
+        struct rc_pid_events_file_info *file_info = file->private_data;
+
+        poll_wait(file, &file_info->events->waitqueue, wait);
+
+        return POLLIN | POLLRDNORM;
+}
+
+#define RC_PID_PRINT_BUF_SIZE 64
+
+static ssize_t rate_control_pid_events_read(struct file *file, char __user *buf,
+                                            size_t length, loff_t *offset)
+{
+        struct rc_pid_events_file_info *file_info = file->private_data;
+        struct rc_pid_event_buffer *events = file_info->events;
+        struct rc_pid_event *ev;
+        char pb[RC_PID_PRINT_BUF_SIZE];
+        int ret;
+        int p;
+        unsigned int status;
+
+        /* Check if there is something to read. */
+        if (events->next_entry == file_info->next_entry) {
+                if (file->f_flags & O_NONBLOCK)
+                        return -EAGAIN;
+
+                /* Wait */
+                ret = wait_event_interruptible(events->waitqueue,
+                                events->next_entry != file_info->next_entry);
+
+                if (ret)
+                        return ret;
+        }
+
+        /* Write out one event per call. I don't care whether it's a little
+         * inefficient, this is debugging code anyway. */
+        spin_lock_irqsave(&events->lock, status);
+
+        /* Get an event */
+        ev = &(events->ring[file_info->next_entry]);
+        file_info->next_entry = (file_info->next_entry + 1) %
+                                RC_PID_EVENT_RING_SIZE;
+
+        /* Print information about the event. Note that userpace needs to
+         * provide large enough buffers. */
+        length = length < RC_PID_PRINT_BUF_SIZE ?
+                 length : RC_PID_PRINT_BUF_SIZE;
+        p = snprintf(pb, length, "%u %lu ", ev->id, ev->timestamp);
+        switch (ev->type) {
+        case RC_PID_EVENT_TYPE_TX_STATUS:
+                p += snprintf(pb + p, length - p, "tx_status %u %u",
+                              ev->data.tx_status.excessive_retries,
+                              ev->data.tx_status.retry_count);
+                break;
+        case RC_PID_EVENT_TYPE_RATE_CHANGE:
+                p += snprintf(pb + p, length - p, "rate_change %d %d",
+                              ev->data.index, ev->data.rate);
+                break;
+        case RC_PID_EVENT_TYPE_TX_RATE:
+                p += snprintf(pb + p, length - p, "tx_rate %d %d",
+                              ev->data.index, ev->data.rate);
+                break;
+        case RC_PID_EVENT_TYPE_PF_SAMPLE:
+                p += snprintf(pb + p, length - p,
+                              "pf_sample %d %d %d %d",
+                              ev->data.pf_sample, ev->data.prop_err,
+                              ev->data.int_err, ev->data.der_err);
+                break;
+        }
+        p += snprintf(pb + p, length - p, "\n");
+
+        spin_unlock_irqrestore(&events->lock, status);
+
+        if (copy_to_user(buf, pb, p))
+                return -EFAULT;
+
+        return p;
+}
+
+#undef RC_PID_PRINT_BUF_SIZE
+
+struct file_operations rc_pid_fop_events = {
+        .owner = THIS_MODULE,
+        .read = rate_control_pid_events_read,
+        .poll = rate_control_pid_events_poll,
+        .open = rate_control_pid_events_open,
+        .release = rate_control_pid_events_release,
+};
+
+void rate_control_pid_add_sta_debugfs(void *priv, void *priv_sta,
+                                             struct dentry *dir)
+{
+        struct rc_pid_sta_info *spinfo = priv_sta;
+
+        spinfo->events_entry = debugfs_create_file("rc_pid_events", S_IRUGO,
+                                                   dir, spinfo,
+                                                   &rc_pid_fop_events);
+}
+
+void rate_control_pid_remove_sta_debugfs(void *priv, void *priv_sta)
+{
+        struct rc_pid_sta_info *spinfo = priv_sta;
+
+        debugfs_remove(spinfo->events_entry);
+}