net: ipa: use IDs for last allocated transaction

Use the allocated and free transaction IDs to determine whether the
"last" transaction used for quiescing a channel is in allocated
state.  The last allocated transaction that has not been committed
(if any) immediately precedes the first free transaction in the
transaction array.

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 0ea98fa5dee56b95e66339edf49d6317bf5462f1..135e51980d793efa76760bf56d633ef708790621 100644 (file)
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -711,6 +711,8 @@ static struct gsi_trans *gsi_channel_trans_last(struct gsi_channel *channel)
 {
        struct gsi_trans_info *trans_info = &channel->trans_info;
        struct gsi_trans *trans;
+       u16 trans_index;
+       u16 trans_id;
 
        spin_lock_bh(&trans_info->spinlock);
 
@@ -718,10 +720,14 @@ static struct gsi_trans *gsi_channel_trans_last(struct gsi_channel *channel)
         * before we disabled transmits, so check for that.
         */
        if (channel->toward_ipa) {
-               trans = list_last_entry_or_null(&trans_info->alloc,
-                                               struct gsi_trans, links);
-               if (trans)
+               /* The last allocated transaction precedes the first free */
+               if (trans_info->allocated_id != trans_info->free_id) {
+                       trans_id = trans_info->free_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->committed,
                                                struct gsi_trans, links);
                if (trans)