i40e: introduce next_to_process to i40e_ring

Add a new field called next_to_process in the i40e_ring that is
advanced for every buffer and change the semantics of next_to_clean to
point to the first buffer of a packet. Driver will use next_to_process
in the same way next_to_clean was used previously.

For the non multi-buffer case, next_to_process and next_to_clean will
always be the same since each packet consists of a single buffer.

Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index e34595c..7fa35ff 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1524,6 +1524,7 @@ skip_free:
 
        rx_ring->next_to_alloc = 0;
        rx_ring->next_to_clean = 0;
+       rx_ring->next_to_process = 0;
        rx_ring->next_to_use = 0;
 }
 
@@ -1576,6 +1577,7 @@ int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring)
 
        rx_ring->next_to_alloc = 0;
        rx_ring->next_to_clean = 0;
+       rx_ring->next_to_process = 0;
        rx_ring->next_to_use = 0;
 
        /* XDP RX-queue info only needed for RX rings exposed to XDP */
@@ -2076,7 +2078,7 @@ static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,
 {
        struct i40e_rx_buffer *rx_buffer;
 
-       rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
+       rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_process);
        rx_buffer->page_count =
 #if (PAGE_SIZE < 8192)
                page_count(rx_buffer->page);
@@ -2375,16 +2377,16 @@ void i40e_finalize_xdp_rx(struct i40e_ring *rx_ring, unsigned int xdp_res)
 }
 
 /**
- * i40e_inc_ntc: Advance the next_to_clean index
+ * i40e_inc_ntp: Advance the next_to_process index
  * @rx_ring: Rx ring
  **/
-static void i40e_inc_ntc(struct i40e_ring *rx_ring)
+static void i40e_inc_ntp(struct i40e_ring *rx_ring)
 {
-       u32 ntc = rx_ring->next_to_clean + 1;
+       u32 ntp = rx_ring->next_to_process + 1;
 
-       ntc = (ntc < rx_ring->count) ? ntc : 0;
-       rx_ring->next_to_clean = ntc;
-       prefetch(I40E_RX_DESC(rx_ring, ntc));
+       ntp = (ntp < rx_ring->count) ? ntp : 0;
+       rx_ring->next_to_process = ntp;
+       prefetch(I40E_RX_DESC(rx_ring, ntp));
 }
 
 /**
@@ -2421,6 +2423,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
        xdp_prog = READ_ONCE(rx_ring->xdp_prog);
 
        while (likely(total_rx_packets < (unsigned int)budget)) {
+               u16 ntp = rx_ring->next_to_process;
                struct i40e_rx_buffer *rx_buffer;
                union i40e_rx_desc *rx_desc;
                unsigned int size;
@@ -2433,7 +2436,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
                        cleaned_count = 0;
                }
 
-               rx_desc = I40E_RX_DESC(rx_ring, rx_ring->next_to_clean);
+               rx_desc = I40E_RX_DESC(rx_ring, ntp);
 
                /* status_error_len will always be zero for unused descriptors
                 * because it's cleared in cleanup, and overlaps with hdr_addr
@@ -2452,8 +2455,8 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
                        i40e_clean_programming_status(rx_ring,
                                                      rx_desc->raw.qword[0],
                                                      qword);
-                       rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
-                       i40e_inc_ntc(rx_ring);
+                       rx_buffer = i40e_rx_bi(rx_ring, ntp);
+                       i40e_inc_ntp(rx_ring);
                        i40e_reuse_rx_page(rx_ring, rx_buffer);
                        cleaned_count++;
                        continue;
@@ -2509,7 +2512,8 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
                i40e_put_rx_buffer(rx_ring, rx_buffer);
                cleaned_count++;
 
-               i40e_inc_ntc(rx_ring);
+               i40e_inc_ntp(rx_ring);
+               rx_ring->next_to_clean = rx_ring->next_to_process;
                if (i40e_is_non_eop(rx_ring, rx_desc))
                        continue;
 

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
index eec4a4a..75888a9 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
@@ -337,6 +337,10 @@ struct i40e_ring {
        u8 dcb_tc;                      /* Traffic class of ring */
        u8 __iomem *tail;
 
+       /* Next descriptor to be processed; next_to_clean is updated only on
+        * processing EOP descriptor
+        */
+       u16 next_to_process;
        /* high bit set means dynamic, use accessor routines to read/write.
         * hardware only supports 2us resolution for the ITR registers.
         * these values always store the USER setting, and must be converted