1 files changed, 80 insertions, 35 deletions

diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
index bbea1ccfd46a..681ec22b9d0e 100644
--- a/Documentation/hwmon/hpfall.c
+++ b/Documentation/hwmon/hpfall.c
@@ -16,6 +16,34 @@
 #include <stdint.h>
 #include <errno.h>
 #include <signal.h>
+#include <sys/mman.h>
+#include <sched.h>
+
+char unload_heads_path[64];
+
+int set_unload_heads_path(char *device)
+{
+        char devname[64];
+
+        if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
+                return -EINVAL;
+        strncpy(devname, device + 5, sizeof(devname));
+
+        snprintf(unload_heads_path, sizeof(unload_heads_path),
+                                "/sys/block/%s/device/unload_heads", devname);
+        return 0;
+}
+int valid_disk(void)
+{
+        int fd = open(unload_heads_path, O_RDONLY);
+        if (fd < 0) {
+                perror(unload_heads_path);
+                return 0;
+        }
+
+        close(fd);
+        return 1;
+}
 
 void write_int(char *path, int i)
 {
@@ -40,7 +68,7 @@ void set_led(int on)
 
 void protect(int seconds)
 {
-        write_int("/sys/block/sda/device/unload_heads", seconds*1000);
+        write_int(unload_heads_path, seconds*1000);
 }
 
 int on_ac(void)
@@ -57,45 +85,62 @@ void ignore_me(void)
 {
         protect(0);
         set_led(0);
-
 }
 
-int main(int argc, char* argv[])
+int main(int argc, char **argv)
 {
-       int fd, ret;
+        int fd, ret;
+        struct sched_param param;
+
+        if (argc == 1)
+                ret = set_unload_heads_path("/dev/sda");
+        else if (argc == 2)
+                ret = set_unload_heads_path(argv[1]);
+        else
+                ret = -EINVAL;
+
+        if (ret || !valid_disk()) {
+                fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
+                                argv[0]);
+                exit(1);
+        }
+
+        fd = open("/dev/freefall", O_RDONLY);
+        if (fd < 0) {
+                perror("/dev/freefall");
+                return EXIT_FAILURE;
+        }
 
-       fd = open("/dev/freefall", O_RDONLY);
-       if (fd < 0) {
-               perror("open");
-               return EXIT_FAILURE;
-       }
+        daemon(0, 0);
+        param.sched_priority = sched_get_priority_max(SCHED_FIFO);
+        sched_setscheduler(0, SCHED_FIFO, &param);
+        mlockall(MCL_CURRENT|MCL_FUTURE);
 
         signal(SIGALRM, ignore_me);
 
-       for (;;) {
-               unsigned char count;
-
-               ret = read(fd, &count, sizeof(count));
-               alarm(0);
-               if ((ret == -1) && (errno == EINTR)) {
-                       /* Alarm expired, time to unpark the heads */
-                       continue;
-               }
-
-               if (ret != sizeof(count)) {
-                       perror("read");
-                       break;
-               }
-
-               protect(21);
-               set_led(1);
-               if (1 || on_ac() || lid_open()) {
-                       alarm(2);
-               } else {
-                       alarm(20);
-               }
-       }
-
-       close(fd);
-       return EXIT_SUCCESS;
+        for (;;) {
+                unsigned char count;
+
+                ret = read(fd, &count, sizeof(count));
+                alarm(0);
+                if ((ret == -1) && (errno == EINTR)) {
+                        /* Alarm expired, time to unpark the heads */
+                        continue;
+                }
+
+                if (ret != sizeof(count)) {
+                        perror("read");
+                        break;
+                }
+
+                protect(21);
+                set_led(1);
+                if (1 || on_ac() || lid_open())
+                        alarm(2);
+                else
+                        alarm(20);
+        }
+
+        close(fd);
+        return EXIT_SUCCESS;
 }