mmc: convert to idr_alloc()

Convert to the much saner new idr interface.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Chris Ball <cjb@laptop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/mmc/core/host.c

@@ -429,19 +429,20 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 	int err;
 	struct mmc_host *host;
 
-	if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
-		return NULL;
-
 	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
 	if (!host)
 		return NULL;
 
 	/* scanning will be enabled when we're ready */
 	host->rescan_disable = 1;
+	idr_preload(GFP_KERNEL);
 	spin_lock(&mmc_host_lock);
-	err = idr_get_new(&mmc_host_idr, host, &host->index);
+	err = idr_alloc(&mmc_host_idr, host, 0, 0, GFP_NOWAIT);
+	if (err >= 0)
+		host->index = err;
 	spin_unlock(&mmc_host_lock);
-	if (err)
+	idr_preload_end();
+	if (err < 0)
 		goto free;
 
 	dev_set_name(&host->class_dev, "mmc%d", host->index);