net: ipa: use IDs exclusively for last transaction

Always use transaction IDs when finding the "last" transaction to
await when quiescing a channel.  This basically extends what was
done in the previous patch to all other transaction state IDs.

As a result we are no longer updating any transaction lists inside
gsi_channel_trans_last(), so there's no need to take the spinlock.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 135e51980d793efa76760bf56d633ef708790621..0983a11409f2d1797a4eaecf540074ce754415f0 100644 (file)
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -714,8 +714,6 @@ static struct gsi_trans *gsi_channel_trans_last(struct gsi_channel *channel)
        u16 trans_index;
        u16 trans_id;
 
-       spin_lock_bh(&trans_info->spinlock);
-
        /* There is a small chance a TX transaction got allocated just
         * before we disabled transmits, so check for that.
         */
@@ -728,32 +726,46 @@ static struct gsi_trans *gsi_channel_trans_last(struct gsi_channel *channel)
                        goto done;
                }
 
-               trans = list_last_entry_or_null(&trans_info->committed,
-                                               struct gsi_trans, links);
-               if (trans)
+               /* Last committed transaction precedes the first allocated */
+               if (trans_info->committed_id != trans_info->allocated_id) {
+                       trans_id = trans_info->allocated_id - 1;
+                       trans_index = trans_id % channel->tre_count;
+                       trans = &trans_info->trans[trans_index];
                        goto done;
-               trans = list_last_entry_or_null(&trans_info->pending,
-                                               struct gsi_trans, links);
-               if (trans)
+               }
+
+               /* Last pending transaction precedes the first committed */
+               if (trans_info->pending_id != trans_info->committed_id) {
+                       trans_id = trans_info->committed_id - 1;
+                       trans_index = trans_id % channel->tre_count;
+                       trans = &trans_info->trans[trans_index];
                        goto done;
+               }
        }
 
        /* Otherwise (TX or RX) we want to wait for anything that
         * has completed, or has been polled but not released yet.
+        *
+        * The last pending transaction precedes the first committed.
         */
-       trans = list_last_entry_or_null(&trans_info->complete,
-                                       struct gsi_trans, links);
-       if (trans)
+       if (trans_info->completed_id != trans_info->pending_id) {
+               trans_id = trans_info->pending_id - 1;
+               trans_index = trans_id % channel->tre_count;
+               trans = &trans_info->trans[trans_index];
                goto done;
-       trans = list_last_entry_or_null(&trans_info->polled,
-                                       struct gsi_trans, links);
+       }
+       if (trans_info->polled_id != trans_info->completed_id) {
+               trans_id = trans_info->completed_id - 1;
+               trans_index = trans_id % channel->tre_count;
+               trans = &trans_info->trans[trans_index];
+       } else {
+               trans = NULL;
+       }
 done:
        /* Caller will wait for this, so take a reference */
        if (trans)
                refcount_inc(&trans->refcount);
 
-       spin_unlock_bh(&trans_info->spinlock);
-
        return trans;
 }