iwlwifi: process multiple frames per RXB

The flow handler (hardware) can put multiple
frames into a single RX buffer. To handle
this, walk the RX buffer and check if there
are multiple valid packets in it.

To let the upper layer handle this correctly
introduce rxb_offset() which is needed when
we pass pages to mac80211 -- we need to know
the offset into the page there.

Also change the page handling scheme to use
refcounting. Anyone who needs a page will
"steal" it, which marks it as having been
used & refcounts it. The RX handler then has
to free its own reference and must not reuse
the page.

Finally, do not set the bit asking the FH to
give us each packet in a single buffer. This
really enables the feature.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index 0c81cbaa8088..57d8ae7b7ba9 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -162,6 +162,8 @@ struct iwl_cmd_header {
 
 
 #define FH_RSCSR_FRAME_SIZE_MSK		0x00003FFF	/* bits 0-13 */
+#define FH_RSCSR_FRAME_INVALID		0x55550000
+#define FH_RSCSR_FRAME_ALIGN		0x40
 
 struct iwl_rx_packet {
 	/*
@@ -260,18 +262,25 @@ static inline void iwl_free_resp(struct iwl_host_cmd *cmd)
 
 struct iwl_rx_cmd_buffer {
 	struct page *_page;
+	int _offset;
+	bool _page_stolen;
 };
 
 static inline void *rxb_addr(struct iwl_rx_cmd_buffer *r)
 {
-	return page_address(r->_page);
+	return (void *)((unsigned long)page_address(r->_page) + r->_offset);
+}
+
+static inline int rxb_offset(struct iwl_rx_cmd_buffer *r)
+{
+	return r->_offset;
 }
 
 static inline struct page *rxb_steal_page(struct iwl_rx_cmd_buffer *r)
 {
-	struct page *p = r->_page;
-	r->_page = NULL;
-	return p;
+	r->_page_stolen = true;
+	get_page(r->_page);
+	return r->_page;
 }
 
 #define MAX_NO_RECLAIM_CMDS	6