btrfs: replace opencoded kvzalloc with the helper

The logic of kmalloc and vmalloc fallback is opencoded in
several places, we can now use the existing helper.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/check-integrity.c

@@ -94,7 +94,7 @@
 #include <linux/mutex.h>
 #include <linux/genhd.h>
 #include <linux/blkdev.h>
-#include <linux/vmalloc.h>
+#include <linux/mm.h>
 #include <linux/string.h>
 #include "ctree.h"
 #include "disk-io.h"
@@ -2920,14 +2920,11 @@ int btrfsic_mount(struct btrfs_fs_info *fs_info,
 		       fs_info->sectorsize, PAGE_SIZE);
 		return -1;
 	}
-	state = kzalloc(sizeof(*state), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
+	state = kvzalloc(sizeof(*state), GFP_KERNEL);
 	if (!state) {
-		state = vzalloc(sizeof(*state));
-		if (!state) {
-			pr_info("btrfs check-integrity: vzalloc() failed!\n");
+		pr_info("btrfs check-integrity: allocation failed!\n");
 		return -1;
 	}
-	}
 
 	if (!btrfsic_is_initialized) {
 		mutex_init(&btrfsic_mutex);

fs/btrfs/raid56.c

@@ -31,7 +31,7 @@
 #include <linux/hash.h>
 #include <linux/list_sort.h>
 #include <linux/raid/xor.h>
-#include <linux/vmalloc.h>
+#include <linux/mm.h>
 #include <asm/div64.h>
 #include "ctree.h"
 #include "extent_map.h"
@@ -218,12 +218,9 @@ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
 	 * of a failing mount.
 	 */
 	table_size = sizeof(*table) + sizeof(*h) * num_entries;
-	table = kzalloc(table_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
-	if (!table) {
-		table = vzalloc(table_size);
+	table = kvzalloc(table_size, GFP_KERNEL);
 	if (!table)
 		return -ENOMEM;
-	}
 
 	spin_lock_init(&table->cache_lock);
 	INIT_LIST_HEAD(&table->stripe_cache);

fs/btrfs/send.c

@@ -6389,14 +6389,11 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
 
 	alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
 
-	sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN);
-	if (!sctx->clone_roots) {
-		sctx->clone_roots = vzalloc(alloc_size);
+	sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL);
 	if (!sctx->clone_roots) {
 		ret = -ENOMEM;
 		goto out;
 	}
-	}
 
 	alloc_size = arg->clone_sources_count * sizeof(*arg->clone_sources);