[PATCH 05/21] EDAC: Introduce mci_for_each_dimm() iterator

[Robert Richter]

Make code more readable by introducing a mci_for_each_dimm() iterator.
Now, we just get a pointer to a struct dimm_info. Direct array access
using an index is no longer needed to iterate.

Signed-off-by: Robert Richter <rrichter@xxxxxxxxxxx>
---
 drivers/edac/edac_mc.c       | 18 ++++++++++--------
 drivers/edac/edac_mc_sysfs.c | 34 +++++++++++++++-------------------
 drivers/edac/ghes_edac.c     |  8 ++++----
 drivers/edac/i5100_edac.c    | 11 +++++------
 include/linux/edac.h         |  7 +++++++
 5 files changed, 41 insertions(+), 37 deletions(-)

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 07edbd80af07..a6b34ccce3d4 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -145,15 +145,18 @@ static void edac_mc_dump_channel(struct rank_info *chan)
 	edac_dbg(4, "    channel->dimm = %p\n", chan->dimm);
 }
 
-static void edac_mc_dump_dimm(struct dimm_info *dimm, int number)
+static void edac_mc_dump_dimm(struct dimm_info *dimm)
 {
 	char location[80];
 
+	if (!dimm->nr_pages)
+		return;
+
 	edac_dimm_info_location(dimm, location, sizeof(location));
 
 	edac_dbg(4, "%s%i: %smapped as virtual row %d, chan %d\n",
 		 dimm->mci->csbased ? "rank" : "dimm",
-		 number, location, dimm->csrow, dimm->cschannel);
+		 dimm->idx, location, dimm->csrow, dimm->cschannel);
 	edac_dbg(4, "  dimm = %p\n", dimm);
 	edac_dbg(4, "  dimm->label = '%s'\n", dimm->label);
 	edac_dbg(4, "  dimm->nr_pages = 0x%x\n", dimm->nr_pages);
@@ -703,6 +706,7 @@ EXPORT_SYMBOL_GPL(edac_get_owner);
 int edac_mc_add_mc_with_groups(struct mem_ctl_info *mci,
 			       const struct attribute_group **groups)
 {
+	struct dimm_info *dimm;
 	int ret = -EINVAL;
 	edac_dbg(0, "\n");
 
@@ -727,9 +731,8 @@ int edac_mc_add_mc_with_groups(struct mem_ctl_info *mci,
 				if (csrow->channels[j]->dimm->nr_pages)
 					edac_mc_dump_channel(csrow->channels[j]);
 		}
-		for (i = 0; i < mci->tot_dimms; i++)
-			if (mci->dimms[i]->nr_pages)
-				edac_mc_dump_dimm(mci->dimms[i], i);
+		mci_for_each_dimm(mci, dimm)
+			edac_mc_dump_dimm(dimm);
 	}
 #endif
 	mutex_lock(&mem_ctls_mutex);
@@ -1087,6 +1090,7 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
 			  const char *msg,
 			  const char *other_detail)
 {
+	struct dimm_info *dimm;
 	char *p;
 	int row = -1, chan = -1;
 	int pos[EDAC_MAX_LAYERS] = { top_layer, mid_layer, low_layer };
@@ -1147,9 +1151,7 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
 	p = e->label;
 	*p = '\0';
 
-	for (i = 0; i < mci->tot_dimms; i++) {
-		struct dimm_info *dimm = mci->dimms[i];
-
+	mci_for_each_dimm(mci, dimm) {
 		if (top_layer >= 0 && top_layer != dimm->location[0])
 			continue;
 		if (mid_layer >= 0 && mid_layer != dimm->location[1])
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 8beefa699a49..75cba0812a16 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -622,8 +622,7 @@ static const struct device_type dimm_attr_type = {
 
 /* Create a DIMM object under specifed memory controller device */
 static int edac_create_dimm_object(struct mem_ctl_info *mci,
-				   struct dimm_info *dimm,
-				   int index)
+				   struct dimm_info *dimm)
 {
 	int err;
 	dimm->mci = mci;
@@ -633,9 +632,9 @@ static int edac_create_dimm_object(struct mem_ctl_info *mci,
 
 	dimm->dev.parent = &mci->dev;
 	if (mci->csbased)
-		dev_set_name(&dimm->dev, "rank%d", index);
+		dev_set_name(&dimm->dev, "rank%d", dimm->idx);
 	else
-		dev_set_name(&dimm->dev, "dimm%d", index);
+		dev_set_name(&dimm->dev, "dimm%d", dimm->idx);
 	dev_set_drvdata(&dimm->dev, dimm);
 	pm_runtime_forbid(&mci->dev);
 
@@ -909,7 +908,8 @@ static const struct device_type mci_attr_type = {
 int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
 				 const struct attribute_group **groups)
 {
-	int i, err;
+	struct dimm_info *dimm;
+	int err;
 
 	/* get the /sys/devices/system/edac subsys reference */
 	mci->dev.type = &mci_attr_type;
@@ -932,14 +932,13 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
 	/*
 	 * Create the dimm/rank devices
 	 */
-	for (i = 0; i < mci->tot_dimms; i++) {
-		struct dimm_info *dimm = mci->dimms[i];
+	mci_for_each_dimm(mci, dimm) {
 		/* Only expose populated DIMMs */
 		if (!dimm->nr_pages)
 			continue;
 
 #ifdef CONFIG_EDAC_DEBUG
-		edac_dbg(1, "creating dimm%d, located at ", i);
+		edac_dbg(1, "creating dimm%d, located at ", dimm->idx);
 		if (edac_debug_level >= 1) {
 			int lay;
 			for (lay = 0; lay < mci->n_layers; lay++)
@@ -949,9 +948,10 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
 			printk(KERN_CONT "\n");
 		}
 #endif
-		err = edac_create_dimm_object(mci, dimm, i);
+		err = edac_create_dimm_object(mci, dimm);
 		if (err) {
-			edac_dbg(1, "failure: create dimm %d obj\n", i);
+			edac_dbg(1, "failure: create dimm %d obj\n",
+				dimm->idx);
 			goto fail_unregister_dimm;
 		}
 	}
@@ -966,12 +966,9 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
 	return 0;
 
 fail_unregister_dimm:
-	for (i--; i >= 0; i--) {
-		struct dimm_info *dimm = mci->dimms[i];
-		if (!dimm->nr_pages)
-			continue;
-
-		device_unregister(&dimm->dev);
+	mci_for_each_dimm(mci, dimm) {
+		if (device_is_registered(&dimm->dev))
+			device_unregister(&dimm->dev);
 	}
 	device_unregister(&mci->dev);
 
@@ -983,7 +980,7 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
  */
 void edac_remove_sysfs_mci_device(struct mem_ctl_info *mci)
 {
-	int i;
+	struct dimm_info *dimm;
 
 	edac_dbg(0, "\n");
 
@@ -994,8 +991,7 @@ void edac_remove_sysfs_mci_device(struct mem_ctl_info *mci)
 	edac_delete_csrow_objects(mci);
 #endif
 
-	for (i = 0; i < mci->tot_dimms; i++) {
-		struct dimm_info *dimm = mci->dimms[i];
+	mci_for_each_dimm(mci, dimm) {
 		if (dimm->nr_pages == 0)
 			continue;
 		edac_dbg(0, "removing device %s\n", dev_name(&dimm->dev));
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 42afa2604db3..fe45392f0c3e 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -84,11 +84,11 @@ static void ghes_edac_count_dimms(const struct dmi_header *dh, void *arg)
 static int get_dimm_smbios_index(u16 handle)
 {
 	struct mem_ctl_info *mci = ghes_pvt->mci;
-	int i;
+	struct dimm_info *dimm;
 
-	for (i = 0; i < mci->tot_dimms; i++) {
-		if (mci->dimms[i]->smbios_handle == handle)
-			return i;
+	mci_for_each_dimm(mci, dimm) {
+		if (dimm->smbios_handle == handle)
+			return dimm->idx;
 	}
 	return -1;
 }
diff --git a/drivers/edac/i5100_edac.c b/drivers/edac/i5100_edac.c
index 39ba7f2414ae..7ec42b26a716 100644
--- a/drivers/edac/i5100_edac.c
+++ b/drivers/edac/i5100_edac.c
@@ -846,14 +846,13 @@ static void i5100_init_interleaving(struct pci_dev *pdev,
 
 static void i5100_init_csrows(struct mem_ctl_info *mci)
 {
-	int i;
 	struct i5100_priv *priv = mci->pvt_info;
+	struct dimm_info *dimm;
 
-	for (i = 0; i < mci->tot_dimms; i++) {
-		struct dimm_info *dimm;
-		const unsigned long npages = i5100_npages(mci, i);
-		const unsigned chan = i5100_csrow_to_chan(mci, i);
-		const unsigned rank = i5100_csrow_to_rank(mci, i);
+	mci_for_each_dimm(mci, dimm) {
+		const unsigned long npages = i5100_npages(mci, dimm->idx);
+		const unsigned chan = i5100_csrow_to_chan(mci, dimm->idx);
+		const unsigned rank = i5100_csrow_to_rank(mci, dimm->idx);
 
 		if (!npages)
 			continue;
diff --git a/include/linux/edac.h b/include/linux/edac.h
index 2ee9b8598ae0..20a04f48616c 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -599,6 +599,13 @@ struct mem_ctl_info {
 	u16 fake_inject_count;
 };
 
+#define mci_for_each_dimm(mci, dimm)			\
+	for ((dimm) = (mci)->dimms[0];			\
+	     (dimm);					\
+	     (dimm) = (dimm)->idx < (mci)->tot_dimms	\
+		     ? (mci)->dimms[(dimm)->idx + 1]	\
+		     : NULL)
+
 /**
  * edac_get_dimm_by_index - Get DIMM info from a memory controller
  *                          given by an index
-- 
2.20.1