qcacmn: Lock rx_desc_pool to collect nbufs and delete later

When multi page alloc is activated, spinlock for rx_desc_pool
is being held for more than 2 seconds, resulting in QDF_BUG.
The major proportion of the time period is used in unmapping
the nbufs.
To fix this, lock rx_desc_pool only to collect nbufs from
rx_desc in a list and unmap and free the nbufs after releasing
the lock.

Change-Id: Iff2078a0de56b51712e2f9a7c5ace7a959e2445d
CRs-Fixed: 2779498

dp/wifi3.0/dp_rx.h

@@ -846,6 +846,12 @@ void dp_rx_process_mic_error(struct dp_soc *soc, qdf_nbuf_t nbuf,
 void dp_2k_jump_handle(struct dp_soc *soc, qdf_nbuf_t nbuf, uint8_t *rx_tlv_hdr,
 		       uint16_t peer_id, uint8_t tid);
 
+#define DP_RX_HEAD_APPEND(head, elem) \
+	do {                                                            \
+		qdf_nbuf_set_next((elem), (head));			\
+		(head) = (elem);                                        \
+	} while (0)
+
 
 #define DP_RX_LIST_APPEND(head, tail, elem) \
 	do {                                                          \

dp/wifi3.0/dp_rx_desc.c

@@ -148,22 +148,21 @@ union dp_rx_desc_list_elem_t *dp_rx_desc_find(uint16_t page_id, uint16_t offset,
 		rx_desc_pool->elem_size * offset;
 }
 
-static QDF_STATUS __dp_rx_desc_nbuf_free(struct dp_soc *soc,
-					 struct rx_desc_pool *rx_desc_pool)
+static QDF_STATUS dp_rx_desc_nbuf_collect(struct dp_soc *soc,
+					  struct rx_desc_pool *rx_desc_pool,
+					  qdf_nbuf_t *nbuf_unmap_list,
+					  qdf_nbuf_t *nbuf_free_list)
 {
 	uint32_t i, num_desc, page_id, offset, num_desc_per_page;
 	union dp_rx_desc_list_elem_t *rx_desc_elem;
 	struct dp_rx_desc *rx_desc;
-	qdf_nbuf_t nbuf;
 
-	if (qdf_unlikely(!(rx_desc_pool->
-					desc_pages.cacheable_pages))) {
+	if (qdf_unlikely(!(rx_desc_pool->desc_pages.cacheable_pages))) {
 		qdf_err("No pages found on this desc pool");
 		return QDF_STATUS_E_INVAL;
 	}
 	num_desc = rx_desc_pool->pool_size;
-	num_desc_per_page =
-		rx_desc_pool->desc_pages.num_element_per_page;
+	num_desc_per_page = rx_desc_pool->desc_pages.num_element_per_page;
 	for (i = 0; i < num_desc; i++) {
 		page_id = i / num_desc_per_page;
 		offset = i % num_desc_per_page;
@@ -171,47 +170,72 @@ static QDF_STATUS __dp_rx_desc_nbuf_free(struct dp_soc *soc,
 		rx_desc = &rx_desc_elem->rx_desc;
 		dp_rx_desc_free_dbg_info(rx_desc);
 		if (rx_desc->in_use) {
-			nbuf = rx_desc->nbuf;
 			if (!rx_desc->unmapped) {
-				dp_ipa_handle_rx_buf_smmu_mapping(
-							soc, nbuf,
-							rx_desc_pool->buf_size,
-							false);
-				qdf_nbuf_unmap_nbytes_single(
-							soc->osdev,
-							rx_desc->nbuf,
-							QDF_DMA_BIDIRECTIONAL,
-							rx_desc_pool->buf_size);
+				DP_RX_HEAD_APPEND(*nbuf_unmap_list,
+						  rx_desc->nbuf);
 				rx_desc->unmapped = 1;
+			} else {
+				DP_RX_HEAD_APPEND(*nbuf_free_list,
+						  rx_desc->nbuf);
 			}
-			qdf_nbuf_free(nbuf);
 		}
 	}
-
 	return QDF_STATUS_SUCCESS;
 }
 
+static void dp_rx_desc_nbuf_cleanup(struct dp_soc *soc,
+				    qdf_nbuf_t nbuf_unmap_list,
+				    qdf_nbuf_t nbuf_free_list,
+				    uint16_t buf_size)
+{
+	qdf_nbuf_t nbuf = nbuf_unmap_list;
+	qdf_nbuf_t next;
+
+	while (nbuf) {
+		next = nbuf->next;
+		if (dp_ipa_handle_rx_buf_smmu_mapping(soc, nbuf, buf_size,
+						      false))
+			dp_info_rl("Unable to unmap nbuf: %pK", nbuf);
+		qdf_nbuf_unmap_nbytes_single(soc->osdev, nbuf,
+					     QDF_DMA_BIDIRECTIONAL, buf_size);
+		qdf_nbuf_free(nbuf);
+		nbuf = next;
+	}
+
+	nbuf = nbuf_free_list;
+	while (nbuf) {
+		next = nbuf->next;
+		qdf_nbuf_free(nbuf);
+		nbuf = next;
+	}
+}
+
 void dp_rx_desc_nbuf_and_pool_free(struct dp_soc *soc, uint32_t pool_id,
 				   struct rx_desc_pool *rx_desc_pool)
 {
-	QDF_STATUS qdf_status;
+	qdf_nbuf_t nbuf_unmap_list = NULL;
+	qdf_nbuf_t nbuf_free_list = NULL;
 
 	qdf_spin_lock_bh(&rx_desc_pool->lock);
-	qdf_status = __dp_rx_desc_nbuf_free(soc, rx_desc_pool);
-	if (QDF_IS_STATUS_SUCCESS(qdf_status))
-		dp_rx_desc_pool_free(soc, rx_desc_pool);
-
+	dp_rx_desc_nbuf_collect(soc, rx_desc_pool,
+				&nbuf_unmap_list, &nbuf_free_list);
 	qdf_spin_unlock_bh(&rx_desc_pool->lock);
-
+	dp_rx_desc_nbuf_cleanup(soc, nbuf_unmap_list, nbuf_free_list,
+				rx_desc_pool->buf_size);
 	qdf_spinlock_destroy(&rx_desc_pool->lock);
 }
 
 void dp_rx_desc_nbuf_free(struct dp_soc *soc,
 			  struct rx_desc_pool *rx_desc_pool)
 {
+	qdf_nbuf_t nbuf_unmap_list = NULL;
+	qdf_nbuf_t nbuf_free_list = NULL;
 	qdf_spin_lock_bh(&rx_desc_pool->lock);
-	__dp_rx_desc_nbuf_free(soc, rx_desc_pool);
+	dp_rx_desc_nbuf_collect(soc, rx_desc_pool,
+				&nbuf_unmap_list, &nbuf_free_list);
 	qdf_spin_unlock_bh(&rx_desc_pool->lock);
+	dp_rx_desc_nbuf_cleanup(soc, nbuf_unmap_list, nbuf_free_list,
+				rx_desc_pool->buf_size);
 }
 
 void dp_rx_desc_pool_free(struct dp_soc *soc,