cdrom: use list_head for cdrom_device_info list

Use list_head for cdrom_device_info list instead of opencoded
singly list handling.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 8 insertions, 24 deletions

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 326ef1b4a4ea..c4213b7d0b20 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -362,7 +362,7 @@ static int cdrom_get_disc_info(struct cdrom_device_info *cdi, disc_information *
 
 static void cdrom_sysctl_register(void);
 
-static struct cdrom_device_info *topCdromPtr;
+static LIST_HEAD(cdrom_list);
 
 static int cdrom_dummy_generic_packet(struct cdrom_device_info *cdi,
                                       struct packet_command *cgc)
@@ -436,35 +436,18 @@ int register_cdrom(struct cdrom_device_info *cdi)
 
         cdinfo(CD_REG_UNREG, "drive \"/dev/%s\" registered\n", cdi->name);
         mutex_lock(&cdrom_mutex);
-        cdi->next = topCdromPtr;        
-        topCdromPtr = cdi;
+        list_add(&cdi->list, &cdrom_list);
         mutex_unlock(&cdrom_mutex);
         return 0;
 }
 #undef ENSURE
 
-int unregister_cdrom(struct cdrom_device_info *unreg)
+int unregister_cdrom(struct cdrom_device_info *cdi)
 {
-        struct cdrom_device_info *cdi, *prev;
         cdinfo(CD_OPEN, "entering unregister_cdrom\n"); 
 
-        prev = NULL;
         mutex_lock(&cdrom_mutex);
-        cdi = topCdromPtr;
-        while (cdi && cdi != unreg) {
-                prev = cdi;
-                cdi = cdi->next;
-        }
-
-        if (cdi == NULL) {
-                mutex_unlock(&cdrom_mutex);
-                return -2;
-        }
-        if (prev)
-                prev->next = cdi->next;
-        else
-                topCdromPtr = cdi->next;
-
+        list_del(&cdi->list);
         mutex_unlock(&cdrom_mutex);
 
         if (cdi->exit)
@@ -3306,7 +3289,7 @@ static int cdrom_print_info(const char *header, int val, char *info,
 
         *pos += ret;
 
-        for (cdi = topCdromPtr; cdi; cdi = cdi->next) {
+        list_for_each_entry(cdi, &cdrom_list, list) {
                 switch (option) {
                 case CTL_NAME:
                         ret = scnprintf(info + *pos, max_size - *pos,
@@ -3428,7 +3411,7 @@ static void cdrom_update_settings(void)
         struct cdrom_device_info *cdi;
 
         mutex_lock(&cdrom_mutex);
-        for (cdi = topCdromPtr; cdi != NULL; cdi = cdi->next) {
+        list_for_each_entry(cdi, &cdrom_list, list) {
                 if (autoclose && CDROM_CAN(CDC_CLOSE_TRAY))
                         cdi->options |= CDO_AUTO_CLOSE;
                 else if (!autoclose)
diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h
index a5cd2047624e..40e05d0a6e45 100644
--- a/include/linux/cdrom.h
+++ b/include/linux/cdrom.h
@@ -910,6 +910,7 @@ struct mode_page_header {
 #ifdef __KERNEL__
 #include <linux/fs.h>           /* not really needed, later.. */
 #include <linux/device.h>
+#include <linux/list.h>
 
 struct packet_command
 {
@@ -934,7 +935,7 @@ struct packet_command
 /* Uniform cdrom data structures for cdrom.c */
 struct cdrom_device_info {
         struct cdrom_device_ops  *ops;  /* link to device_ops */
-        struct cdrom_device_info *next; /* next device_info for this major */
+        struct list_head list;          /* linked list of all device_info */
         struct gendisk *disk;           /* matching block layer disk */
         void *handle;                   /* driver-dependent data */
 /* specifications */