mac80211: use a counter for remain-on-channel cookie

Instead of using the pointer which can be re-used
fairly quickly due to allocator patterns and then
makes debugging difficult, maintain a counter and
use its value. Since it's a 64-bit value it can't
really wrap, but catch that case anyway since it
most likely points to a bug somewhere.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 986e9a1..eebb70b 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2382,13 +2382,22 @@ static int ieee80211_start_roc_work(struct ieee80211_local *local,
                list_add_tail(&roc->list, &local->roc_list);
 
        /*
-        * cookie is either the roc (for normal roc)
+        * cookie is either the roc cookie (for normal roc)
         * or the SKB (for mgmt TX)
         */
-       if (txskb)
+       if (!txskb) {
+               /* local->mtx protects this */
+               local->roc_cookie_counter++;
+               roc->cookie = local->roc_cookie_counter;
+               /* wow, you wrapped 64 bits ... more likely a bug */
+               if (WARN_ON(roc->cookie == 0)) {
+                       roc->cookie = 1;
+                       local->roc_cookie_counter++;
+               }
+               *cookie = roc->cookie;
+       } else {
                *cookie = (unsigned long)txskb;
-       else
-               *cookie = (unsigned long)roc;
+       }
 
        return 0;
 }
@@ -2423,7 +2432,7 @@ static int ieee80211_cancel_roc(struct ieee80211_local *local,
                struct ieee80211_roc_work *dep, *tmp2;
 
                list_for_each_entry_safe(dep, tmp2, &roc->dependents, list) {
-                       if (!mgmt_tx && (unsigned long)dep != cookie)
+                       if (!mgmt_tx && dep->cookie != cookie)
                                continue;
                        else if (mgmt_tx && dep->mgmt_tx_cookie != cookie)
                                continue;
@@ -2435,7 +2444,7 @@ static int ieee80211_cancel_roc(struct ieee80211_local *local,
                        return 0;
                }
 
-               if (!mgmt_tx && (unsigned long)roc != cookie)
+               if (!mgmt_tx && roc->cookie != cookie)
                        continue;
                else if (mgmt_tx && roc->mgmt_tx_cookie != cookie)
                        continue;

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a1f7c13..d272e0c 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -356,7 +356,7 @@ struct ieee80211_roc_work {
 
        u32 duration, req_duration;
        struct sk_buff *frame;
-       u64 mgmt_tx_cookie;
+       u64 cookie, mgmt_tx_cookie;
 };
 
 /* flags used in struct ieee80211_if_managed.flags */
@@ -1142,6 +1142,7 @@ struct ieee80211_local {
        struct list_head roc_list;
        struct work_struct hw_roc_start, hw_roc_done;
        unsigned long hw_roc_start_time;
+       u64 roc_cookie_counter;
 
        struct idr ack_status_frames;
        spinlock_t ack_status_lock;

diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index c349f3a..0cd42d5 100644 (file)
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -204,7 +204,7 @@ void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
                        roc->frame = NULL;
                }
        } else {
-               cfg80211_ready_on_channel(&roc->sdata->wdev, (unsigned long)roc,
+               cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
                                          roc->chan, roc->chan_type,
                                          roc->req_duration, GFP_KERNEL);
        }
@@ -320,9 +320,8 @@ void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
 
        if (!roc->mgmt_tx_cookie)
                cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
-                                                  (unsigned long)roc,
-                                                  roc->chan, roc->chan_type,
-                                                  GFP_KERNEL);
+                                                  roc->cookie, roc->chan,
+                                                  roc->chan_type, GFP_KERNEL);
 
        list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
                ieee80211_roc_notify_destroy(dep);