Hello Johannes,
Please take a look at the patch below which handles all the
comments that have been discussed in this thread.
I will appreciate if you review the same and let me know your thoughts
before I send the final patch.
On Fri, Apr 15, 2011 at 04:01:44AM -0700, Johannes Berg wrote:
> On Fri, 2011-04-15 at 16:21 +0530, Yogesh Ashok Powar wrote:
>
> > > > Then Skip the code which expands the skb iff
> > > > IEEE80211_CRYPTO_NO_TAILROOM_NEEDED is set and the key is programmed
> > > > into the hardware (checking KEY_FLAG_UPLOADED_TO_HARDWARE).
> > >
> > > You don't know the key at this point, so you have to keep track of
> > > whether this is true for all keys, which depends on whether or not
> > > they're already programmed into the HW (since for SW crypto we need the
> > > tailroom)
> > From this it seems that we do not reserve tailroom iff
> > IEEE80211_KEY_FLAG_GENERATE_MMIC flag is unset for all keys and all the keys
> > are programmed into the hardware.
> >
> > Also, say in mixed mode if TKIP and CCMP keys are configured and this
> > flag is set for TKIP MMIC, we will end up reserving tailroom even for
> > CCMP. Is my understanding correct?
>
> Yes, correct.
>
> > Also, though I have not looked into this part of the code very closely,
> > how about deriving key information at this place? Will that be feasible?
>
> No, we can't do it here. I suppose we could postpone it for per key
> stuff, but that's more complex and probably good for a separate patch.
>
> johannes
>
Thanks
Yogesh
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a778499..20476ee 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -764,6 +764,9 @@ struct ieee80211_local {
/* device is started */
bool started;
+ /* count for keys needing tailroom space allocation */
+ int crypto_tx_tailroom_needed_cnt;
+
int tx_headroom; /* required headroom for hardware/radiotap */
/* Tasklet and skb queue to process calls from IRQ mode. All frames
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index af3c564..86b88fa 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -101,6 +101,9 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
if (!ret) {
key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
+ if (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)
+ key->local->crypto_tx_tailroom_needed_cnt++;
+
return 0;
}
@@ -117,6 +120,11 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
case WLAN_CIPHER_SUITE_CCMP:
case WLAN_CIPHER_SUITE_AES_CMAC:
/* all of these we can do in software */
+
+ /* SW encryption need tailroom reservation */
+ BUG_ON(!key->local);
+ key->local->crypto_tx_tailroom_needed_cnt++;
+
return 0;
default:
return -EINVAL;
@@ -156,6 +164,11 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
+
+ if ((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)
+ && key->local->crypto_tx_tailroom_needed_cnt)
+ key->local->crypto_tx_tailroom_needed_cnt--;
+
}
void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
@@ -370,8 +383,11 @@ struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
return key;
}
-static void __ieee80211_key_destroy(struct ieee80211_key *key)
+static void __ieee80211_key_destroy(struct ieee80211_local *local,
+ struct ieee80211_key *key)
{
+ bool key_sw_programmed = true;
+
if (!key)
return;
@@ -381,6 +397,8 @@ static void __ieee80211_key_destroy(struct ieee80211_key *key)
*/
synchronize_rcu();
+ key_sw_programmed = !(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE);
+
if (key->local)
ieee80211_key_disable_hw_accel(key);
@@ -391,6 +409,9 @@ static void __ieee80211_key_destroy(struct ieee80211_key *key)
if (key->local)
ieee80211_debugfs_key_remove(key);
+ if (key_sw_programmed && local->crypto_tx_tailroom_needed_cnt)
+ local->crypto_tx_tailroom_needed_cnt--;
+
kfree(key);
}
@@ -447,7 +468,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
old_key = sdata->keys[idx];
__ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
- __ieee80211_key_destroy(old_key);
+ __ieee80211_key_destroy(sdata->local, old_key);
ieee80211_debugfs_key_add(key);
@@ -458,7 +479,8 @@ int ieee80211_key_link(struct ieee80211_key *key,
return ret;
}
-static void __ieee80211_key_free(struct ieee80211_key *key)
+static void __ieee80211_key_free(struct ieee80211_local *local,
+ struct ieee80211_key *key)
{
/*
* Replace key with nothingness if it was ever used.
@@ -467,7 +489,7 @@ static void __ieee80211_key_free(struct ieee80211_key *key)
__ieee80211_key_replace(key->sdata, key->sta,
key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
key, NULL);
- __ieee80211_key_destroy(key);
+ __ieee80211_key_destroy(local, key);
}
void ieee80211_key_free(struct ieee80211_local *local,
@@ -477,7 +499,7 @@ void ieee80211_key_free(struct ieee80211_local *local,
return;
mutex_lock(&local->key_mtx);
- __ieee80211_key_free(key);
+ __ieee80211_key_free(local, key);
mutex_unlock(&local->key_mtx);
}
@@ -521,7 +543,7 @@ void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
ieee80211_debugfs_key_remove_mgmt_default(sdata);
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
- __ieee80211_key_free(key);
+ __ieee80211_key_free(sdata->local, key);
ieee80211_debugfs_key_update_default(sdata);
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 0ab2a8d..1f2aa4d 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -619,6 +619,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
local->user_power_level = -1;
local->uapsd_queues = IEEE80211_DEFAULT_UAPSD_QUEUES;
local->uapsd_max_sp_len = IEEE80211_DEFAULT_MAX_SP_LEN;
+ local->crypto_tx_tailroom_needed_cnt = 0;
INIT_LIST_HEAD(&local->interfaces);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 17b10be..39cdcf5 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1487,7 +1487,7 @@ static int ieee80211_skb_resize(struct ieee80211_local *local,
* crypto (including TKIP MMIC) need no tailroom... But we
* have no drivers for such devices currently.
*/
- if (may_encrypt) {
+ if (may_encrypt && local->crypto_tx_tailroom_needed_cnt) {
tail_need = IEEE80211_ENCRYPT_TAILROOM;
tail_need -= skb_tailroom(skb);
tail_need = max_t(int, tail_need, 0);
--
1.5.4.1
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