diff mbox series

[net-next,v3,RESEND,4/4] octeon_ep: remove atomic variable usage in Tx data path

Message ID 20231114134535.2455051-5-srasheed@marvell.com (mailing list archive)
State Accepted
Commit dc9c02b7faa0f37a1dd52752192a665319657d14
Delegated to: Netdev Maintainers
Headers show
Series Cleanup and optimizations to transmit code | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 1161 this patch: 1161
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1161 this patch: 1161
netdev/checkpatch warning WARNING: line length of 86 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Shinas Rasheed Nov. 14, 2023, 1:45 p.m. UTC
Replace atomic variable "instr_pending" which represents number of
posted tx instructions pending completion, with host_write_idx and
flush_index variables in the xmit and completion processing respectively.

Signed-off-by: Shinas Rasheed <srasheed@marvell.com>
---
V3:
  - No changes.
V2: https://lore.kernel.org/all/20231024145119.2366588-5-srasheed@marvell.com/
  - No changes.
V1: https://lore.kernel.org/all/20231023114449.2362147-4-srasheed@marvell.com/

 drivers/net/ethernet/marvell/octeon_ep/octep_config.h | 1 +
 drivers/net/ethernet/marvell/octeon_ep/octep_main.c   | 9 +++------
 drivers/net/ethernet/marvell/octeon_ep/octep_main.h   | 9 +++++++++
 drivers/net/ethernet/marvell/octeon_ep/octep_tx.c     | 5 +----
 drivers/net/ethernet/marvell/octeon_ep/octep_tx.h     | 3 ---
 5 files changed, 14 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_config.h b/drivers/net/ethernet/marvell/octeon_ep/octep_config.h
index ed8b1ace56b9..91cfa19c65b9 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_config.h
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_config.h
@@ -13,6 +13,7 @@ 
 #define OCTEP_64BYTE_INSTR  64
 
 /* Tx Queue: maximum descriptors per ring */
+/* This needs to be a power of 2 */
 #define OCTEP_IQ_MAX_DESCRIPTORS    1024
 /* Minimum input (Tx) requests to be enqueued to ring doorbell */
 #define OCTEP_DB_MIN                8
diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
index 2d1bcdc589f3..974a34be9ffa 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
@@ -777,7 +777,7 @@  static int octep_stop(struct net_device *netdev)
  */
 static inline int octep_iq_full_check(struct octep_iq *iq)
 {
-	if (likely((iq->max_count - atomic_read(&iq->instr_pending)) >=
+	if (likely((IQ_INSTR_SPACE(iq)) >
 		   OCTEP_WAKE_QUEUE_THRESHOLD))
 		return 0;
 
@@ -794,7 +794,7 @@  static inline int octep_iq_full_check(struct octep_iq *iq)
 	/* check again and restart the queue, in case NAPI has just freed
 	 * enough Tx ring entries.
 	 */
-	if (unlikely((iq->max_count - atomic_read(&iq->instr_pending)) >=
+	if (unlikely(IQ_INSTR_SPACE(iq) >
 		     OCTEP_WAKE_QUEUE_THRESHOLD)) {
 		netif_start_subqueue(iq->netdev, iq->q_no);
 		iq->stats.restart_cnt++;
@@ -903,12 +903,9 @@  static netdev_tx_t octep_start_xmit(struct sk_buff *skb,
 	__netdev_tx_sent_queue(iq->netdev_q, skb->len, xmit_more);
 
 	skb_tx_timestamp(skb);
-	atomic_inc(&iq->instr_pending);
 	iq->fill_cnt++;
 	wi++;
-	if (wi == iq->max_count)
-		wi = 0;
-	iq->host_write_index = wi;
+	iq->host_write_index = wi & iq->ring_size_mask;
 
 	/* octep_iq_full_check stops the queue and returns
 	 * true if so, in case the queue has become full
diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.h b/drivers/net/ethernet/marvell/octeon_ep/octep_main.h
index 6df902ebb7f3..c33e046b69a4 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.h
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.h
@@ -40,6 +40,15 @@ 
 #define  OCTEP_OQ_INTR_RESEND_BIT  59
 
 #define  OCTEP_MMIO_REGIONS     3
+
+#define  IQ_INSTR_PENDING(iq)  ({ typeof(iq) iq__ = (iq); \
+				  ((iq__)->host_write_index - (iq__)->flush_index) & \
+				  (iq__)->ring_size_mask; \
+				})
+#define  IQ_INSTR_SPACE(iq)    ({ typeof(iq) iq_ = (iq); \
+				  (iq_)->max_count - IQ_INSTR_PENDING(iq_); \
+				})
+
 /* PCI address space mapping information.
  * Each of the 3 address spaces given by BAR0, BAR2 and BAR4 of
  * Octeon gets mapped to different physical address spaces in
diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_tx.c b/drivers/net/ethernet/marvell/octeon_ep/octep_tx.c
index d0adb82d65c3..06851b78aa28 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_tx.c
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_tx.c
@@ -21,7 +21,6 @@  static void octep_iq_reset_indices(struct octep_iq *iq)
 	iq->flush_index = 0;
 	iq->pkts_processed = 0;
 	iq->pkt_in_done = 0;
-	atomic_set(&iq->instr_pending, 0);
 }
 
 /**
@@ -82,7 +81,6 @@  int octep_iq_process_completions(struct octep_iq *iq, u16 budget)
 	}
 
 	iq->pkts_processed += compl_pkts;
-	atomic_sub(compl_pkts, &iq->instr_pending);
 	iq->stats.instr_completed += compl_pkts;
 	iq->stats.bytes_sent += compl_bytes;
 	iq->stats.sgentry_sent += compl_sg;
@@ -91,7 +89,7 @@  int octep_iq_process_completions(struct octep_iq *iq, u16 budget)
 	netdev_tx_completed_queue(iq->netdev_q, compl_pkts, compl_bytes);
 
 	if (unlikely(__netif_subqueue_stopped(iq->netdev, iq->q_no)) &&
-	    ((iq->max_count - atomic_read(&iq->instr_pending)) >
+	    (IQ_INSTR_SPACE(iq) >
 	     OCTEP_WAKE_QUEUE_THRESHOLD))
 		netif_wake_subqueue(iq->netdev, iq->q_no);
 	return !budget;
@@ -144,7 +142,6 @@  static void octep_iq_free_pending(struct octep_iq *iq)
 		dev_kfree_skb_any(skb);
 	}
 
-	atomic_set(&iq->instr_pending, 0);
 	iq->flush_index = fi;
 	netdev_tx_reset_queue(netdev_get_tx_queue(iq->netdev, iq->q_no));
 }
diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_tx.h b/drivers/net/ethernet/marvell/octeon_ep/octep_tx.h
index 86c98b13fc44..1ba4ff65e54d 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_tx.h
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_tx.h
@@ -172,9 +172,6 @@  struct octep_iq {
 	/* Statistics for this input queue. */
 	struct octep_iq_stats stats;
 
-	/* This field keeps track of the instructions pending in this queue. */
-	atomic_t instr_pending;
-
 	/* Pointer to the Virtual Base addr of the input ring. */
 	struct octep_tx_desc_hw *desc_ring;