[PATCH 39/54] net/bnxt: thor2 truflow memory manager bug

[Manish Kurup]

From: Farah Smith <farah.smith at broadcom.com>

A performance optimization was made based upon the belief that blocks
in the memory manager always had non-full blocks prior to full blocks.
But this is not the case.  The performance optimization stopped looking
for space in the block list as soon as the first full block was found
in the list.  This fix adds code so that whenever a block is full, it is
moved to the end of the list so that the search can stop upon reaching
the first full block.  Remove current_blk_idx.  Adjust max_records based
upon max contiguous.

Signed-off-by: Farah Smith <farah.smith at broadcom.com>
Reviewed-by: Manish Kurup <manish.kurup at broadcom.com>
---
 drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm.c     | 83 ++++++++++++-------
 .../net/bnxt/hcapi/cfa_v3/mm/cfa_mm_priv.h    |  2 +-
 2 files changed, 56 insertions(+), 29 deletions(-)

diff --git a/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm.c b/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm.c
index 05528dd3e4..6e21d513ac 100644
--- a/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm.c
+++ b/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm.c
@@ -48,6 +48,10 @@ int cfa_mm_query(struct cfa_mm_query_parms *parms)
 	max_records = parms->max_records;
 	max_contig_records = (uint16_t)parms->max_contig_records;
 
+	/* Align to max_contig_records */
+	max_records = (max_records + (max_contig_records - 1)) &
+		      ~(max_contig_records - 1);
+
 	if (unlikely(!(CFA_CHECK_BOUNDS(max_records, 1, CFA_MM_MAX_RECORDS) &&
 	      IS_POWER_2(max_contig_records) &&
 	      CFA_CHECK_BOUNDS(max_contig_records, 1,
@@ -79,6 +83,10 @@ int cfa_mm_open(void *cmm, struct cfa_mm_open_parms *parms)
 	max_records = parms->max_records;
 	max_contig_records = (uint16_t)parms->max_contig_records;
 
+	/* Align to max_contig_records */
+	max_records = (max_records + (max_contig_records - 1)) &
+		      ~(max_contig_records - 1);
+
 	if (unlikely(!(CFA_CHECK_BOUNDS(max_records, 1, CFA_MM_MAX_RECORDS) &&
 	      IS_POWER_2(max_contig_records) &&
 	      CFA_CHECK_BOUNDS(max_contig_records, 1,
@@ -115,11 +123,11 @@ int cfa_mm_open(void *cmm, struct cfa_mm_open_parms *parms)
 	context->blk_bmap_tbl = (uint8_t *)(context->blk_tbl + num_blocks);
 
 	context->blk_list_tbl[0].first_blk_idx = 0;
-	context->blk_list_tbl[0].current_blk_idx = 0;
+	context->blk_list_tbl[0].last_blk_idx = 0;
 
 	for (i = 1; i < num_lists; i++) {
 		context->blk_list_tbl[i].first_blk_idx = CFA_MM_INVALID32;
-		context->blk_list_tbl[i].current_blk_idx = CFA_MM_INVALID32;
+		context->blk_list_tbl[i].last_blk_idx = CFA_MM_INVALID32;
 	}
 
 	for (i = 0; i < num_blocks; i++) {
@@ -162,6 +170,7 @@ int cfa_mm_close(void *cmm)
 	return 0;
 }
 
+/* Allocate a block idx from the free list */
 static uint32_t cfa_mm_blk_alloc(struct cfa_mm *context)
 {
 	uint32_t blk_idx;
@@ -179,8 +188,6 @@ static uint32_t cfa_mm_blk_alloc(struct cfa_mm *context)
 	free_list->first_blk_idx =
 		context->blk_tbl[free_list->first_blk_idx].next_blk_idx;
 
-	free_list->current_blk_idx = free_list->first_blk_idx;
-
 	if (free_list->first_blk_idx != CFA_MM_INVALID32) {
 		context->blk_tbl[free_list->first_blk_idx].prev_blk_idx =
 			CFA_MM_INVALID32;
@@ -192,6 +199,7 @@ static uint32_t cfa_mm_blk_alloc(struct cfa_mm *context)
 	return blk_idx;
 }
 
+/* Return a block index to the free list */
 static void cfa_mm_blk_free(struct cfa_mm *context, uint32_t blk_idx)
 {
 	struct cfa_mm_blk_list *free_list = context->blk_list_tbl;
@@ -208,16 +216,17 @@ static void cfa_mm_blk_free(struct cfa_mm *context, uint32_t blk_idx)
 	}
 
 	free_list->first_blk_idx = blk_idx;
-	free_list->current_blk_idx = blk_idx;
 }
 
+/* insert at the top of a non-free list */
 static void cfa_mm_blk_insert(struct cfa_mm *context,
 			      struct cfa_mm_blk_list *blk_list,
 			      uint32_t blk_idx)
 {
+	/* there are no entries in the list so init all to this one */
 	if (blk_list->first_blk_idx == CFA_MM_INVALID32) {
 		blk_list->first_blk_idx = blk_idx;
-		blk_list->current_blk_idx = blk_idx;
+		blk_list->last_blk_idx = blk_idx;
 	} else {
 		struct cfa_mm_blk *blk_info = &context->blk_tbl[blk_idx];
 
@@ -226,10 +235,29 @@ static void cfa_mm_blk_insert(struct cfa_mm *context,
 		context->blk_tbl[blk_list->first_blk_idx].prev_blk_idx =
 			blk_idx;
 		blk_list->first_blk_idx = blk_idx;
-		blk_list->current_blk_idx = blk_idx;
 	}
 }
 
+/* insert at the bottom of a non-free list */
+static void cfa_mm_blk_insert_last(struct cfa_mm *context,
+				   struct cfa_mm_blk_list *blk_list,
+				   uint32_t blk_idx)
+{
+	if (blk_list->last_blk_idx == CFA_MM_INVALID32) {
+		blk_list->first_blk_idx = blk_idx;
+		blk_list->last_blk_idx = blk_idx;
+	} else {
+		struct cfa_mm_blk *blk_info = &context->blk_tbl[blk_idx];
+
+		blk_info->prev_blk_idx = blk_list->last_blk_idx;
+		blk_info->next_blk_idx = CFA_MM_INVALID32;
+		context->blk_tbl[blk_list->last_blk_idx].next_blk_idx =
+			blk_idx;
+		blk_list->last_blk_idx = blk_idx;
+	}
+}
+
+/* delete from anywhere in the list */
 static void cfa_mm_blk_delete(struct cfa_mm *context,
 			      struct cfa_mm_blk_list *blk_list,
 			      uint32_t blk_idx)
@@ -239,15 +267,20 @@ static void cfa_mm_blk_delete(struct cfa_mm *context,
 	if (blk_list->first_blk_idx == CFA_MM_INVALID32)
 		return;
 
+	if (blk_list->last_blk_idx == blk_idx) {
+		blk_list->last_blk_idx = blk_info->prev_blk_idx;
+		if (blk_list->last_blk_idx != CFA_MM_INVALID32) {
+			context->blk_tbl[blk_list->last_blk_idx].next_blk_idx =
+				CFA_MM_INVALID32;
+		}
+	}
+
 	if (blk_list->first_blk_idx == blk_idx) {
 		blk_list->first_blk_idx = blk_info->next_blk_idx;
 		if (blk_list->first_blk_idx != CFA_MM_INVALID32) {
 			context->blk_tbl[blk_list->first_blk_idx].prev_blk_idx =
 				CFA_MM_INVALID32;
 		}
-		if (blk_list->current_blk_idx == blk_idx)
-			blk_list->current_blk_idx = blk_list->first_blk_idx;
-
 		return;
 	}
 
@@ -260,20 +293,6 @@ static void cfa_mm_blk_delete(struct cfa_mm *context,
 		context->blk_tbl[blk_info->next_blk_idx].prev_blk_idx =
 			blk_info->prev_blk_idx;
 	}
-
-	if (blk_list->current_blk_idx == blk_idx) {
-		if (blk_info->next_blk_idx != CFA_MM_INVALID32) {
-			blk_list->current_blk_idx = blk_info->next_blk_idx;
-		} else {
-			if (blk_info->prev_blk_idx != CFA_MM_INVALID32) {
-				blk_list->current_blk_idx =
-					blk_info->prev_blk_idx;
-			} else {
-				blk_list->current_blk_idx =
-					blk_list->first_blk_idx;
-			}
-		}
-	}
 }
 
 /* Returns true if the bit in the bitmap is set to 'val' else returns false */
@@ -413,12 +432,19 @@ int cfa_mm_alloc(void *cmm, struct cfa_mm_alloc_parms *parms)
 
 		blk_info->num_contig_records = num_records;
 	} else {
-		blk_idx = blk_list->current_blk_idx;
+		blk_idx = blk_list->first_blk_idx;
 		blk_info = &context->blk_tbl[blk_idx];
 	}
 
 	while (blk_info->num_free_records < num_records) {
-		if (blk_info->next_blk_idx == CFA_MM_INVALID32 || !blk_info->num_free_records) {
+		/*
+		 * All non-full entries precede full entries so
+		 * upon seeing the first full entry, allocate
+		 * new block as this means all following records
+		 * are full.
+		 */
+		if (blk_info->next_blk_idx == CFA_MM_INVALID32 ||
+		    !blk_info->num_free_records) {
 			blk_idx = cfa_mm_blk_alloc(context);
 			if (unlikely(blk_idx == CFA_MM_INVALID32)) {
 				ret = -ENOMEM;
@@ -433,8 +459,6 @@ int cfa_mm_alloc(void *cmm, struct cfa_mm_alloc_parms *parms)
 		} else {
 			blk_idx = blk_info->next_blk_idx;
 			blk_info = &context->blk_tbl[blk_idx];
-
-			blk_list->current_blk_idx = blk_idx;
 		}
 	}
 
@@ -459,6 +483,9 @@ int cfa_mm_alloc(void *cmm, struct cfa_mm_alloc_parms *parms)
 	blk_info->num_free_records -= num_records;
 
 	if (!blk_info->num_free_records) {
+		/* move block to the end of the list if it is full */
+		cfa_mm_blk_delete(context, blk_list, blk_idx);
+		cfa_mm_blk_insert_last(context, blk_list, blk_idx);
 		blk_info->first_free_record = context->records_per_block;
 	} else {
 		cnt = NUM_ALIGN_UNITS(context->records_per_block,
diff --git a/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm_priv.h b/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm_priv.h
index 2a646217ec..dbac1c3cf2 100644
--- a/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm_priv.h
+++ b/drivers/net/bnxt/hcapi/cfa_v3/mm/cfa_mm_priv.h
@@ -47,7 +47,7 @@ struct cfa_mm_blk_list {
 	/* Index of the first block in the list */
 	uint32_t first_blk_idx;
 	/* Index of the current block having free records */
-	uint32_t current_blk_idx;
+	uint32_t last_blk_idx;
 };
 
 /**
-- 
2.39.5 (Apple Git-154)