[PATCH v2 02/20] EDAC: Remove EDAC_DIMM_OFF() macro

[Robert Richter <rrichter@marvell.com>]

The EDAC_DIMM_OFF() macro takes 5 arguments to get the DIMM's index.
This can be much simplified. Store the index in struct dimm_info to
avoid its calculation and remove the EDAC_DIMM_OFF() macro. The index
can be directly used.

Another advantage is that edac_mc_alloc() could be used even if the
exact size of the layers is unknown. Only the number of DIMMs would be
needed.

Signed-off-by: Robert Richter <rrichter@marvell.com>
---
 drivers/edac/edac_mc.c       | 14 ++++-------
 drivers/edac/edac_mc_sysfs.c | 20 ++++------------
 include/linux/edac.h         | 45 ++++--------------------------------
 3 files changed, 13 insertions(+), 66 deletions(-)

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index e6fd079783bd..72088d49b03b 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -314,10 +314,10 @@ struct mem_ctl_info *edac_mc_alloc(unsigned int mc_num,
 	struct dimm_info *dimm;
 	u32 *ce_per_layer[EDAC_MAX_LAYERS], *ue_per_layer[EDAC_MAX_LAYERS];
 	unsigned int pos[EDAC_MAX_LAYERS];
-	unsigned int size, tot_dimms = 1, count = 1;
+	unsigned int idx, size, tot_dimms = 1, count = 1;
 	unsigned int tot_csrows = 1, tot_channels = 1, tot_errcount = 0;
 	void *pvt, *p, *ptr = NULL;
-	int i, j, row, chn, n, len, off;
+	int i, j, row, chn, n, len;
 	bool per_rank = false;
 
 	BUG_ON(n_layers > EDAC_MAX_LAYERS || n_layers == 0);
@@ -425,19 +425,15 @@ struct mem_ctl_info *edac_mc_alloc(unsigned int mc_num,
 	memset(&pos, 0, sizeof(pos));
 	row = 0;
 	chn = 0;
-	for (i = 0; i < tot_dimms; i++) {
+	for (idx = 0; idx < tot_dimms; idx++) {
 		chan = mci->csrows[row]->channels[chn];
-		off = EDAC_DIMM_OFF(layer, n_layers, pos[0], pos[1], pos[2]);
-		if (off < 0 || off >= tot_dimms) {
-			edac_mc_printk(mci, KERN_ERR, "EDAC core bug: EDAC_DIMM_OFF is trying to do an illegal data access\n");
-			goto error;
-		}
 
 		dimm = kzalloc(sizeof(**mci->dimms), GFP_KERNEL);
 		if (!dimm)
 			goto error;
-		mci->dimms[off] = dimm;
+		mci->dimms[idx] = dimm;
 		dimm->mci = mci;
+		dimm->idx = idx;
 
 		/*
 		 * Copy DIMM location and initialize it.
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 32d016f1ecd1..91e4c8f155af 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -557,14 +557,8 @@ static ssize_t dimmdev_ce_count_show(struct device *dev,
 {
 	struct dimm_info *dimm = to_dimm(dev);
 	u32 count;
-	int off;
-
-	off = EDAC_DIMM_OFF(dimm->mci->layers,
-			    dimm->mci->n_layers,
-			    dimm->location[0],
-			    dimm->location[1],
-			    dimm->location[2]);
-	count = dimm->mci->ce_per_layer[dimm->mci->n_layers-1][off];
+
+	count = dimm->mci->ce_per_layer[dimm->mci->n_layers-1][dimm->idx];
 	return sprintf(data, "%u\n", count);
 }
 
@@ -574,14 +568,8 @@ static ssize_t dimmdev_ue_count_show(struct device *dev,
 {
 	struct dimm_info *dimm = to_dimm(dev);
 	u32 count;
-	int off;
-
-	off = EDAC_DIMM_OFF(dimm->mci->layers,
-			    dimm->mci->n_layers,
-			    dimm->location[0],
-			    dimm->location[1],
-			    dimm->location[2]);
-	count = dimm->mci->ue_per_layer[dimm->mci->n_layers-1][off];
+
+	count = dimm->mci->ue_per_layer[dimm->mci->n_layers-1][dimm->idx];
 	return sprintf(data, "%u\n", count);
 }
 
diff --git a/include/linux/edac.h b/include/linux/edac.h
index 696bfb684d92..79c5564ee314 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -362,47 +362,6 @@ struct edac_mc_layer {
  */
 #define EDAC_MAX_LAYERS		3
 
-/**
- * EDAC_DIMM_OFF - Macro responsible to get a pointer offset inside a pointer
- *		   array for the element given by [layer0,layer1,layer2]
- *		   position
- *
- * @layers:	a struct edac_mc_layer array, describing how many elements
- *		were allocated for each layer
- * @nlayers:	Number of layers at the @layers array
- * @layer0:	layer0 position
- * @layer1:	layer1 position. Unused if n_layers < 2
- * @layer2:	layer2 position. Unused if n_layers < 3
- *
- * For 1 layer, this macro returns "var[layer0] - var";
- *
- * For 2 layers, this macro is similar to allocate a bi-dimensional array
- * and to return "var[layer0][layer1] - var";
- *
- * For 3 layers, this macro is similar to allocate a tri-dimensional array
- * and to return "var[layer0][layer1][layer2] - var".
- *
- * A loop could be used here to make it more generic, but, as we only have
- * 3 layers, this is a little faster.
- *
- * By design, layers can never be 0 or more than 3. If that ever happens,
- * a NULL is returned, causing an OOPS during the memory allocation routine,
- * with would point to the developer that he's doing something wrong.
- */
-#define EDAC_DIMM_OFF(layers, nlayers, layer0, layer1, layer2) ({		\
-	int __i;							\
-	if ((nlayers) == 1)						\
-		__i = layer0;						\
-	else if ((nlayers) == 2)					\
-		__i = (layer1) + ((layers[1]).size * (layer0));		\
-	else if ((nlayers) == 3)					\
-		__i = (layer2) + ((layers[2]).size * ((layer1) +	\
-			    ((layers[1]).size * (layer0))));		\
-	else								\
-		__i = -EINVAL;						\
-	__i;								\
-})
-
 struct dimm_info {
 	struct device dev;
 
@@ -412,6 +371,7 @@ struct dimm_info {
 	unsigned int location[EDAC_MAX_LAYERS];
 
 	struct mem_ctl_info *mci;	/* the parent */
+	unsigned int idx;		/* index within the parent dimm array */
 
 	u32 grain;		/* granularity of reported error in bytes */
 	enum dev_type dtype;	/* memory device type */
@@ -654,6 +614,9 @@ edac_get_dimm_by_index(struct mem_ctl_info *mci, int index)
 	if (index < 0 || index >= mci->tot_dimms)
 		return NULL;
 
+	if (WARN_ON_ONCE(mci->dimms[index]->idx != index))
+		return NULL;
+
 	return mci->dimms[index];
 }
 
-- 
2.20.1