1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/net/wimax/i2400m/tx.c b/drivers/net/wimax/i2400m/tx.c
index 1725f2b022a2..101550a2f5a2 100644
--- a/drivers/net/wimax/i2400m/tx.c
+++ b/drivers/net/wimax/i2400m/tx.c
@@ -396,8 +396,20 @@ void *i2400m_tx_fifo_push(struct i2400m *i2400m, size_t size, size_t padding)
         /* Is there space at the tail? */
         tail_room = __i2400m_tx_tail_room(i2400m);
         if (tail_room < needed_size) {
-                if (i2400m->tx_out % I2400M_TX_BUF_SIZE
-                    < i2400m->tx_in % I2400M_TX_BUF_SIZE) {
+                /*
+                 * If the tail room space is not enough to push the message
+                 * in the TX FIFO, then there are two possibilities:
+                 * 1. There is enough head room space to accommodate
+                 * this message in the TX FIFO.
+                 * 2. There is not enough space in the head room and
+                 * in tail room of the TX FIFO to accommodate the message.
+                 * In the case (1), return TAIL_FULL so that the caller
+                 * can figure out, if the caller wants to push the message
+                 * into the head room space.
+                 * In the case (2), return NULL, indicating that the TX FIFO
+                 * cannot accommodate the message.
+                 */
+                if (room - tail_room >= needed_size) {
                         d_printf(2, dev, "fifo push %zu/%zu: tail full\n",
                                  size, padding);
                         return TAIL_FULL;       /* There might be head space */