libata: clean up lpm related symbols and sysfs show/store functions

Link power management related symbols are in confusing state w/ mixed
usages of lpm, ipm and pm.  This patch cleans up lpm related symbols
and sysfs show/store functions as follows.

* lpm states - NOT_AVAILABLE, MIN_POWER, MAX_PERFORMANCE and
  MEDIUM_POWER are renamed to ATA_LPM_UNKNOWN and
  ATA_LPM_{MIN|MAX|MED}_POWER.

* Pre/postfixes are unified to lpm.

* sysfs show/store functions for link_power_management_policy were
  curiously named get/put and unnecessarily complex.  Renamed to
  show/store and simplified.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 22 insertions, 44 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index f1c0118c6d4b..aa56681f68db 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -103,72 +103,50 @@ static const u8 def_control_mpage[CONTROL_MPAGE_LEN] = {
         0, 30   /* extended self test time, see 05-359r1 */
 };
 
-static const struct {
-        enum link_pm    value;
-        const char      *name;
-} link_pm_policy[] = {
-        { NOT_AVAILABLE, "max_performance" },
-        { MIN_POWER, "min_power" },
-        { MAX_PERFORMANCE, "max_performance" },
-        { MEDIUM_POWER, "medium_power" },
+static const char *ata_lpm_policy_names[] = {
+        [ATA_LPM_UNKNOWN]       = "max_performance",
+        [ATA_LPM_MAX_POWER]     = "max_performance",
+        [ATA_LPM_MED_POWER]     = "medium_power",
+        [ATA_LPM_MIN_POWER]     = "min_power",
 };
 
-static const char *ata_scsi_lpm_get(enum link_pm policy)
-{
-        int i;
-
-        for (i = 0; i < ARRAY_SIZE(link_pm_policy); i++)
-                if (link_pm_policy[i].value == policy)
-                        return link_pm_policy[i].name;
-
-        return NULL;
-}
-
-static ssize_t ata_scsi_lpm_put(struct device *dev,
-                                struct device_attribute *attr,
-                                const char *buf, size_t count)
+static ssize_t ata_scsi_lpm_store(struct device *dev,
+                                  struct device_attribute *attr,
+                                  const char *buf, size_t count)
 {
         struct Scsi_Host *shost = class_to_shost(dev);
         struct ata_port *ap = ata_shost_to_port(shost);
-        enum link_pm policy = 0;
-        int i;
+        enum ata_lpm_policy policy;
 
-        /*
-         * we are skipping array location 0 on purpose - this
-         * is because a value of NOT_AVAILABLE is displayed
-         * to the user as max_performance, but when the user
-         * writes "max_performance", they actually want the
-         * value to match MAX_PERFORMANCE.
-         */
-        for (i = 1; i < ARRAY_SIZE(link_pm_policy); i++) {
-                const int len = strlen(link_pm_policy[i].name);
-                if (strncmp(link_pm_policy[i].name, buf, len) == 0) {
-                        policy = link_pm_policy[i].value;
+        /* UNKNOWN is internal state, iterate from MAX_POWER */
+        for (policy = ATA_LPM_MAX_POWER;
+             policy < ARRAY_SIZE(ata_lpm_policy_names); policy++) {
+                const char *name = ata_lpm_policy_names[policy];
+
+                if (strncmp(name, buf, strlen(name)) == 0)
                         break;
-                }
         }
-        if (!policy)
+        if (policy == ARRAY_SIZE(ata_lpm_policy_names))
                 return -EINVAL;
 
         ata_lpm_schedule(ap, policy);
         return count;
 }
 
-static ssize_t
-ata_scsi_lpm_show(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t ata_scsi_lpm_show(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
 {
         struct Scsi_Host *shost = class_to_shost(dev);
         struct ata_port *ap = ata_shost_to_port(shost);
-        const char *policy =
-                ata_scsi_lpm_get(ap->pm_policy);
 
-        if (!policy)
+        if (ap->lpm_policy >= ARRAY_SIZE(ata_lpm_policy_names))
                 return -EINVAL;
 
-        return snprintf(buf, 23, "%s\n", policy);
+        return snprintf(buf, PAGE_SIZE, "%s\n",
+                        ata_lpm_policy_names[ap->lpm_policy]);
 }
 DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
-                ata_scsi_lpm_show, ata_scsi_lpm_put);
+            ata_scsi_lpm_show, ata_scsi_lpm_store);
 EXPORT_SYMBOL_GPL(dev_attr_link_power_management_policy);
 
 static ssize_t ata_scsi_park_show(struct device *device,