sd: Convert to new IDA API

Allows us to remove an explicit spinlock.
Signed-off-by: NMatthew Wilcox <willy@infradead.org>

drivers/scsi/sd.c

@@ -123,7 +123,6 @@ static void scsi_disk_release(struct device *cdev);
 static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
 static void sd_print_result(const struct scsi_disk *, const char *, int);
 
-static DEFINE_SPINLOCK(sd_index_lock);
 static DEFINE_IDA(sd_index_ida);
 
 /* This semaphore is used to mediate the 0->1 reference get in the
@@ -3339,16 +3338,8 @@ static int sd_probe(struct device *dev)
 	if (!gd)
 		goto out_free;
 
-	do {
-		if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))
-			goto out_put;
-
-		spin_lock(&sd_index_lock);
-		error = ida_get_new(&sd_index_ida, &index);
-		spin_unlock(&sd_index_lock);
-	} while (error == -EAGAIN);
-
-	if (error) {
+	index = ida_alloc(&sd_index_ida, GFP_KERNEL);
+	if (index < 0) {
 		sdev_printk(KERN_WARNING, sdp, "sd_probe: memory exhausted.\n");
 		goto out_put;
 	}
@@ -3392,9 +3383,7 @@ static int sd_probe(struct device *dev)
 	return 0;
 
  out_free_index:
-	spin_lock(&sd_index_lock);
-	ida_remove(&sd_index_ida, index);
-	spin_unlock(&sd_index_lock);
+	ida_free(&sd_index_ida, index);
  out_put:
 	put_disk(gd);
  out_free:
@@ -3459,9 +3448,7 @@ static void scsi_disk_release(struct device *dev)
 	struct scsi_disk *sdkp = to_scsi_disk(dev);
 	struct gendisk *disk = sdkp->disk;
 	
-	spin_lock(&sd_index_lock);
-	ida_remove(&sd_index_ida, sdkp->index);
-	spin_unlock(&sd_index_lock);
+	ida_free(&sd_index_ida, sdkp->index);
 
 	disk->private_data = NULL;
 	put_disk(disk);