EDAC: Use static attribute groups for managing sysfs entries

Instead of manual calls of device_create_file() and
device_remove_file(), use static attribute groups with proper
is_visible callbacks for managing the sysfs entries.

This simplifies the code a lot and avoids the possible races.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: http://lkml.kernel.org/r/1423046938-18111-2-git-send-email-tiwai@suse.de
Signed-off-by: Borislav Petkov <bp@suse.de>

1 files changed, 71 insertions, 88 deletions

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index c84eecb191ef..0bcd64234a03 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -323,13 +323,14 @@ DEVICE_CHANNEL(ch5_dimm_label, S_IRUGO | S_IWUSR,
         channel_dimm_label_show, channel_dimm_label_store, 5);
 
 /* Total possible dynamic DIMM Label attribute file table */
-static struct device_attribute *dynamic_csrow_dimm_attr[] = {
-        &dev_attr_legacy_ch0_dimm_label.attr,
-        &dev_attr_legacy_ch1_dimm_label.attr,
-        &dev_attr_legacy_ch2_dimm_label.attr,
-        &dev_attr_legacy_ch3_dimm_label.attr,
-        &dev_attr_legacy_ch4_dimm_label.attr,
-        &dev_attr_legacy_ch5_dimm_label.attr
+static struct attribute *dynamic_csrow_dimm_attr[] = {
+        &dev_attr_legacy_ch0_dimm_label.attr.attr,
+        &dev_attr_legacy_ch1_dimm_label.attr.attr,
+        &dev_attr_legacy_ch2_dimm_label.attr.attr,
+        &dev_attr_legacy_ch3_dimm_label.attr.attr,
+        &dev_attr_legacy_ch4_dimm_label.attr.attr,
+        &dev_attr_legacy_ch5_dimm_label.attr.attr,
+        NULL
 };
 
 /* possible dynamic channel ce_count attribute files */
@@ -347,13 +348,45 @@ DEVICE_CHANNEL(ch5_ce_count, S_IRUGO,
                    channel_ce_count_show, NULL, 5);
 
 /* Total possible dynamic ce_count attribute file table */
-static struct device_attribute *dynamic_csrow_ce_count_attr[] = {
-        &dev_attr_legacy_ch0_ce_count.attr,
-        &dev_attr_legacy_ch1_ce_count.attr,
-        &dev_attr_legacy_ch2_ce_count.attr,
-        &dev_attr_legacy_ch3_ce_count.attr,
-        &dev_attr_legacy_ch4_ce_count.attr,
-        &dev_attr_legacy_ch5_ce_count.attr
+static struct attribute *dynamic_csrow_ce_count_attr[] = {
+        &dev_attr_legacy_ch0_ce_count.attr.attr,
+        &dev_attr_legacy_ch1_ce_count.attr.attr,
+        &dev_attr_legacy_ch2_ce_count.attr.attr,
+        &dev_attr_legacy_ch3_ce_count.attr.attr,
+        &dev_attr_legacy_ch4_ce_count.attr.attr,
+        &dev_attr_legacy_ch5_ce_count.attr.attr,
+        NULL
+};
+
+static umode_t csrow_dev_is_visible(struct kobject *kobj,
+                                    struct attribute *attr, int idx)
+{
+        struct device *dev = kobj_to_dev(kobj);
+        struct csrow_info *csrow = container_of(dev, struct csrow_info, dev);
+
+        if (idx >= csrow->nr_channels)
+                return 0;
+        /* Only expose populated DIMMs */
+        if (!csrow->channels[idx]->dimm->nr_pages)
+                return 0;
+        return attr->mode;
+}
+
+
+static const struct attribute_group csrow_dev_dimm_group = {
+        .attrs = dynamic_csrow_dimm_attr,
+        .is_visible = csrow_dev_is_visible,
+};
+
+static const struct attribute_group csrow_dev_ce_count_group = {
+        .attrs = dynamic_csrow_ce_count_attr,
+        .is_visible = csrow_dev_is_visible,
+};
+
+static const struct attribute_group *csrow_dev_groups[] = {
+        &csrow_dev_dimm_group,
+        &csrow_dev_ce_count_group,
+        NULL
 };
 
 static inline int nr_pages_per_csrow(struct csrow_info *csrow)
@@ -370,13 +403,12 @@ static inline int nr_pages_per_csrow(struct csrow_info *csrow)
 static int edac_create_csrow_object(struct mem_ctl_info *mci,
                                     struct csrow_info *csrow, int index)
 {
-        int err, chan;
-
         if (csrow->nr_channels > EDAC_NR_CHANNELS)
                 return -ENODEV;
 
         csrow->dev.type = &csrow_attr_type;
         csrow->dev.bus = mci->bus;
+        csrow->dev.groups = csrow_dev_groups;
         device_initialize(&csrow->dev);
         csrow->dev.parent = &mci->dev;
         csrow->mci = mci;
@@ -386,45 +418,13 @@ static int edac_create_csrow_object(struct mem_ctl_info *mci,
         edac_dbg(0, "creating (virtual) csrow node %s\n",
                  dev_name(&csrow->dev));
 
-        err = device_add(&csrow->dev);
-        if (err < 0)
-                return err;
-
-        for (chan = 0; chan < csrow->nr_channels; chan++) {
-                /* Only expose populated DIMMs */
-                if (!csrow->channels[chan]->dimm->nr_pages)
-                        continue;
-                err = device_create_file(&csrow->dev,
-                                         dynamic_csrow_dimm_attr[chan]);
-                if (err < 0)
-                        goto error;
-                err = device_create_file(&csrow->dev,
-                                         dynamic_csrow_ce_count_attr[chan]);
-                if (err < 0) {
-                        device_remove_file(&csrow->dev,
-                                           dynamic_csrow_dimm_attr[chan]);
-                        goto error;
-                }
-        }
-
-        return 0;
-
-error:
-        for (--chan; chan >= 0; chan--) {
-                device_remove_file(&csrow->dev,
-                                        dynamic_csrow_dimm_attr[chan]);
-                device_remove_file(&csrow->dev,
-                                           dynamic_csrow_ce_count_attr[chan]);
-        }
-        put_device(&csrow->dev);
-
-        return err;
+        return device_add(&csrow->dev);
 }
 
 /* Create a CSROW object under specifed edac_mc_device */
 static int edac_create_csrow_objects(struct mem_ctl_info *mci)
 {
-        int err, i, chan;
+        int err, i;
         struct csrow_info *csrow;
 
         for (i = 0; i < mci->nr_csrows; i++) {
@@ -446,14 +446,6 @@ error:
                 csrow = mci->csrows[i];
                 if (!nr_pages_per_csrow(csrow))
                         continue;
-                for (chan = csrow->nr_channels - 1; chan >= 0; chan--) {
-                        if (!csrow->channels[chan]->dimm->nr_pages)
-                                continue;
-                        device_remove_file(&csrow->dev,
-                                                dynamic_csrow_dimm_attr[chan]);
-                        device_remove_file(&csrow->dev,
-                                                dynamic_csrow_ce_count_attr[chan]);
-                }
                 put_device(&mci->csrows[i]->dev);
         }
 
@@ -462,23 +454,13 @@ error:
 
 static void edac_delete_csrow_objects(struct mem_ctl_info *mci)
 {
-        int i, chan;
+        int i;
         struct csrow_info *csrow;
 
         for (i = mci->nr_csrows - 1; i >= 0; i--) {
                 csrow = mci->csrows[i];
                 if (!nr_pages_per_csrow(csrow))
                         continue;
-                for (chan = csrow->nr_channels - 1; chan >= 0; chan--) {
-                        if (!csrow->channels[chan]->dimm->nr_pages)
-                                continue;
-                        edac_dbg(1, "Removing csrow %d channel %d sysfs nodes\n",
-                                 i, chan);
-                        device_remove_file(&csrow->dev,
-                                                dynamic_csrow_dimm_attr[chan]);
-                        device_remove_file(&csrow->dev,
-                                                dynamic_csrow_ce_count_attr[chan]);
-                }
                 device_unregister(&mci->csrows[i]->dev);
         }
 }
@@ -863,7 +845,8 @@ static DEVICE_ATTR(ce_count, S_IRUGO, mci_ce_count_show, NULL);
 static DEVICE_ATTR(max_location, S_IRUGO, mci_max_location_show, NULL);
 
 /* memory scrubber attribute file */
-static DEVICE_ATTR(sdram_scrub_rate, 0, NULL, NULL);
+DEVICE_ATTR(sdram_scrub_rate, 0, mci_sdram_scrub_rate_show,
+            mci_sdram_scrub_rate_store); /* umode set later in is_visible */
 
 static struct attribute *mci_attrs[] = {
         &dev_attr_reset_counters.attr,
@@ -875,11 +858,29 @@ static struct attribute *mci_attrs[] = {
         &dev_attr_ue_count.attr,
         &dev_attr_ce_count.attr,
         &dev_attr_max_location.attr,
+        &dev_attr_sdram_scrub_rate.attr,
         NULL
 };
 
+static umode_t mci_attr_is_visible(struct kobject *kobj,
+                                   struct attribute *attr, int idx)
+{
+        struct device *dev = kobj_to_dev(kobj);
+        struct mem_ctl_info *mci = to_mci(dev);
+        umode_t mode = 0;
+
+        if (attr != &dev_attr_sdram_scrub_rate.attr)
+                return attr->mode;
+        if (mci->get_sdram_scrub_rate)
+                mode |= S_IRUGO;
+        if (mci->set_sdram_scrub_rate)
+                mode |= S_IWUSR;
+        return mode;
+}
+
 static struct attribute_group mci_attr_grp = {
         .attrs  = mci_attrs,
+        .is_visible = mci_attr_is_visible,
 };
 
 static const struct attribute_group *mci_attr_groups[] = {
@@ -1008,23 +1009,6 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci)
                 goto fail_unregister_bus;
         }
 
-        if (mci->set_sdram_scrub_rate || mci->get_sdram_scrub_rate) {
-                if (mci->get_sdram_scrub_rate) {
-                        dev_attr_sdram_scrub_rate.attr.mode |= S_IRUGO;
-                        dev_attr_sdram_scrub_rate.show = &mci_sdram_scrub_rate_show;
-                }
-
-                if (mci->set_sdram_scrub_rate) {
-                        dev_attr_sdram_scrub_rate.attr.mode |= S_IWUSR;
-                        dev_attr_sdram_scrub_rate.store = &mci_sdram_scrub_rate_store;
-                }
-
-                err = device_create_file(&mci->dev, &dev_attr_sdram_scrub_rate);
-                if (err) {
-                        edac_dbg(1, "failure: create sdram_scrub_rate\n");
-                        goto fail_unregister_dev;
-                }
-        }
         /*
          * Create the dimm/rank devices
          */
@@ -1071,7 +1055,6 @@ fail_unregister_dimm:
 
                 device_unregister(&dimm->dev);
         }
-fail_unregister_dev:
         device_unregister(&mci->dev);
 fail_unregister_bus:
         bus_unregister(mci->bus);