[PATCH v2] staging: octeon: fix asymmetric output buffer pool accounting

[PATCH v2] staging: octeon: fix asymmetric output buffer pool accounting

[Priyanshu Singh]

In cvm_oct_configure_common_hw(), when CVMX_FPA_OUTPUT_BUFFER_POOL differs
from CVMX_FPA_PACKET_POOL, 1024 output buffers are allocated and added to
the hardware Free Pool Allocator (FPA) pool. However, in cvm_oct_probe()
(err_tx:) and in cvm_oct_remove(), cvm_oct_mem_empty_fpa() is called with
128 instead of 1024 as the expected buffer count.

This asymmetric accounting causes cvm_oct_free_hw_memory() to report a
false warning ("Freeing of pool 2 had too many buffers (-896)") upon
draining the pool.

Define CVM_OCT_NUM_OUTPUT_BUFFERS in ethernet-defines.h and use this
constant across cvm_oct_configure_common_hw(),
cvm_oct_probe(), and cvm_oct_remove() to ensure symmetric allocation
and deallocation.

This was found via manual code inspection and is compile-tested only.

Signed-off-by: Priyanshu Singh <singhpriyanshu9838@gmail.com>
---
v1 -> v2:
 - Make it clear in commit message that, this was found via code inspection
   and is compile-tested only.
 - Fix missing space typo in commit message.

 drivers/staging/octeon/ethernet-defines.h | 2 ++
 drivers/staging/octeon/ethernet.c         | 9 ++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/octeon/ethernet-defines.h b/drivers/staging/octeon/ethernet-defines.h
index c060374a3da2..3ce7c125ccfd 100644
--- a/drivers/staging/octeon/ethernet-defines.h
+++ b/drivers/staging/octeon/ethernet-defines.h
@@ -37,4 +37,6 @@
 
 #define TOTAL_NUMBER_OF_PORTS		(CVMX_PIP_NUM_INPUT_PORTS + 1)
 
+#define CVM_OCT_NUM_OUTPUT_BUFFERS	1024
+
 #endif /* __ETHERNET_DEFINES_H__ */
diff --git a/drivers/staging/octeon/ethernet.c b/drivers/staging/octeon/ethernet.c
index dea5696a6642..e0e6d40602f0 100644
--- a/drivers/staging/octeon/ethernet.c
+++ b/drivers/staging/octeon/ethernet.c
@@ -162,7 +162,8 @@ static void cvm_oct_configure_common_hw(struct platform_device *pdev)
 			     num_packet_buffers);
 	if (CVMX_FPA_OUTPUT_BUFFER_POOL != CVMX_FPA_PACKET_POOL)
 		cvm_oct_mem_fill_fpa(pdev, CVMX_FPA_OUTPUT_BUFFER_POOL,
-				     CVMX_FPA_OUTPUT_BUFFER_POOL_SIZE, 1024);
+				     CVMX_FPA_OUTPUT_BUFFER_POOL_SIZE,
+				     CVM_OCT_NUM_OUTPUT_BUFFERS);
 
 #ifdef __LITTLE_ENDIAN
 	{
@@ -974,7 +975,8 @@ static int cvm_oct_probe(struct platform_device *pdev)
 			      num_packet_buffers);
 	if (CVMX_FPA_OUTPUT_BUFFER_POOL != CVMX_FPA_PACKET_POOL)
 		cvm_oct_mem_empty_fpa(pdev, CVMX_FPA_OUTPUT_BUFFER_POOL,
-				      CVMX_FPA_OUTPUT_BUFFER_POOL_SIZE, 128);
+				      CVMX_FPA_OUTPUT_BUFFER_POOL_SIZE,
+				      CVM_OCT_NUM_OUTPUT_BUFFERS);
 
 	return ret;
 }
@@ -1009,7 +1011,8 @@ static void cvm_oct_remove(struct platform_device *pdev)
 			      num_packet_buffers);
 	if (CVMX_FPA_OUTPUT_BUFFER_POOL != CVMX_FPA_PACKET_POOL)
 		cvm_oct_mem_empty_fpa(pdev, CVMX_FPA_OUTPUT_BUFFER_POOL,
-				      CVMX_FPA_OUTPUT_BUFFER_POOL_SIZE, 128);
+				      CVMX_FPA_OUTPUT_BUFFER_POOL_SIZE,
+				      CVM_OCT_NUM_OUTPUT_BUFFERS);
 }
 
 static const struct of_device_id cvm_oct_match[] = {
-- 
2.53.0