Revert "iwlwifi: pcie: New RBD allocation model"

This reverts commit 5f175703.

This patch introduced a high latency in buffer allocation
under extreme load. This latency caused a firmwre crash.
The same scenario works fine with this patch reverted.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/iwl-fh.h

@@ -438,6 +438,12 @@ static inline unsigned int FH_MEM_CBBC_QUEUE(unsigned int chnl)
 #define RX_QUEUE_MASK                         255
 #define RX_QUEUE_SIZE_LOG                     8
 
+/*
+ * RX related structures and functions
+ */
+#define RX_FREE_BUFFERS 64
+#define RX_LOW_WATERMARK 8
+
 /**
  * struct iwl_rb_status - reserve buffer status
  * 	host memory mapped FH registers

drivers/net/wireless/iwlwifi/pcie/internal.h

@@ -44,15 +44,6 @@
 #include "iwl-io.h"
 #include "iwl-op-mode.h"
 
-/*
- * RX related structures and functions
- */
-#define RX_NUM_QUEUES 1
-#define RX_POST_REQ_ALLOC 2
-#define RX_CLAIM_REQ_ALLOC 8
-#define RX_POOL_SIZE ((RX_CLAIM_REQ_ALLOC - RX_POST_REQ_ALLOC) * RX_NUM_QUEUES)
-#define RX_LOW_WATERMARK 8
-
 struct iwl_host_cmd;
 
 /*This file includes the declaration that are internal to the
@@ -86,29 +77,29 @@ struct isr_statistics {
  * struct iwl_rxq - Rx queue
  * @bd: driver's pointer to buffer of receive buffer descriptors (rbd)
  * @bd_dma: bus address of buffer of receive buffer descriptors (rbd)
+ * @pool:
+ * @queue:
  * @read: Shared index to newest available Rx buffer
  * @write: Shared index to oldest written Rx packet
  * @free_count: Number of pre-allocated buffers in rx_free
- * @used_count: Number of RBDs handled to allocator to use for allocation
  * @write_actual:
- * @rx_free: list of RBDs with allocated RB ready for use
- * @rx_used: list of RBDs with no RB attached
+ * @rx_free: list of free SKBs for use
+ * @rx_used: List of Rx buffers with no SKB
  * @need_update: flag to indicate we need to update read/write index
  * @rb_stts: driver's pointer to receive buffer status
  * @rb_stts_dma: bus address of receive buffer status
  * @lock:
- * @pool: initial pool of iwl_rx_mem_buffer for the queue
- * @queue: actual rx queue
  *
  * NOTE:  rx_free and rx_used are used as a FIFO for iwl_rx_mem_buffers
  */
 struct iwl_rxq {
 	__le32 *bd;
 	dma_addr_t bd_dma;
+	struct iwl_rx_mem_buffer pool[RX_QUEUE_SIZE + RX_FREE_BUFFERS];
+	struct iwl_rx_mem_buffer *queue[RX_QUEUE_SIZE];
 	u32 read;
 	u32 write;
 	u32 free_count;
-	u32 used_count;
 	u32 write_actual;
 	struct list_head rx_free;
 	struct list_head rx_used;
@@ -116,32 +107,6 @@ struct iwl_rxq {
 	struct iwl_rb_status *rb_stts;
 	dma_addr_t rb_stts_dma;
 	spinlock_t lock;
-	struct iwl_rx_mem_buffer pool[RX_QUEUE_SIZE];
-	struct iwl_rx_mem_buffer *queue[RX_QUEUE_SIZE];
-};
-
-/**
- * struct iwl_rb_allocator - Rx allocator
- * @pool: initial pool of allocator
- * @req_pending: number of requests the allcator had not processed yet
- * @req_ready: number of requests honored and ready for claiming
- * @rbd_allocated: RBDs with pages allocated and ready to be handled to
- *	the queue. This is a list of &struct iwl_rx_mem_buffer
- * @rbd_empty: RBDs with no page attached for allocator use. This is a list
- *	of &struct iwl_rx_mem_buffer
- * @lock: protects the rbd_allocated and rbd_empty lists
- * @alloc_wq: work queue for background calls
- * @rx_alloc: work struct for background calls
- */
-struct iwl_rb_allocator {
-	struct iwl_rx_mem_buffer pool[RX_POOL_SIZE];
-	atomic_t req_pending;
-	atomic_t req_ready;
-	struct list_head rbd_allocated;
-	struct list_head rbd_empty;
-	spinlock_t lock;
-	struct workqueue_struct *alloc_wq;
-	struct work_struct rx_alloc;
 };
 
 struct iwl_dma_ptr {
@@ -285,7 +250,7 @@ iwl_pcie_get_scratchbuf_dma(struct iwl_txq *txq, int idx)
 /**
  * struct iwl_trans_pcie - PCIe transport specific data
  * @rxq: all the RX queue data
- * @rba: allocator for RX replenishing
+ * @rx_replenish: work that will be called when buffers need to be allocated
  * @drv - pointer to iwl_drv
  * @trans: pointer to the generic transport area
  * @scd_base_addr: scheduler sram base address in SRAM
@@ -308,7 +273,7 @@ iwl_pcie_get_scratchbuf_dma(struct iwl_txq *txq, int idx)
  */
 struct iwl_trans_pcie {
 	struct iwl_rxq rxq;
-	struct iwl_rb_allocator rba;
+	struct work_struct rx_replenish;
 	struct iwl_trans *trans;
 	struct iwl_drv *drv;