treewide: use kv[mz]alloc* rather than opencoded variants

There are many code paths opencoding kvmalloc.  Let's use the helper
instead.  The main difference to kvmalloc is that those users are
usually not considering all the aspects of the memory allocator.  E.g.
allocation requests <= 32kB (with 4kB pages) are basically never failing
and invoke OOM killer to satisfy the allocation.  This sounds too
disruptive for something that has a reasonable fallback - the vmalloc.
On the other hand those requests might fallback to vmalloc even when the
memory allocator would succeed after several more reclaim/compaction
attempts previously.  There is no guarantee something like that happens
though.

This patch converts many of those places to kv[mz]alloc* helpers because
they are more conservative.

Link: http://lkml.kernel.org/r/20170306103327.2766-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> # Xen bits
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Andreas Dilger <andreas.dilger@intel.com> # Lustre
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> # KVM/s390
Acked-by: Dan Williams <dan.j.williams@intel.com> # nvdim
Acked-by: David Sterba <dsterba@suse.com> # btrfs
Acked-by: Ilya Dryomov <idryomov@gmail.com> # Ceph
Acked-by: Tariq Toukan <tariqt@mellanox.com> # mlx4
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx5
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Santosh Raspatur <santosh@chelsio.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Yishai Hadas <yishaih@mellanox.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: "Yan, Zheng" <zyan@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 15 insertions, 30 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 7dc8844037e0..1c3b6c54d5ee 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -5392,13 +5392,10 @@ int btrfs_compare_trees(struct btrfs_root *left_root,
 		goto out;
 	}
 
-	tmp_buf = kmalloc(fs_info->nodesize, GFP_KERNEL | __GFP_NOWARN);
+	tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
 	if (!tmp_buf) {
-		tmp_buf = vmalloc(fs_info->nodesize);
-		if (!tmp_buf) {
-			ret = -ENOMEM;
-			goto out;
-		}
+		ret = -ENOMEM;
+		goto out;
 	}
 
 	left_path->search_commit_root = 1;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index dabfc7ac48a6..922a66fce401 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3539,12 +3539,9 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 	u64 last_dest_end = destoff;
 
 	ret = -ENOMEM;
-	buf = kmalloc(fs_info->nodesize, GFP_KERNEL | __GFP_NOWARN);
-	if (!buf) {
-		buf = vmalloc(fs_info->nodesize);
-		if (!buf)
-			return ret;
-	}
+	buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
+	if (!buf)
+		return ret;
 
 	path = btrfs_alloc_path();
 	if (!path) {
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index a60d5bfb8a49..3f645cd67b54 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -6360,22 +6360,16 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
 	sctx->clone_roots_cnt = arg->clone_sources_count;
 
 	sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
-	sctx->send_buf = kmalloc(sctx->send_max_size, GFP_KERNEL | __GFP_NOWARN);
+	sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
 	if (!sctx->send_buf) {
-		sctx->send_buf = vmalloc(sctx->send_max_size);
-		if (!sctx->send_buf) {
-			ret = -ENOMEM;
-			goto out;
-		}
+		ret = -ENOMEM;
+		goto out;
 	}
 
-	sctx->read_buf = kmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL | __GFP_NOWARN);
+	sctx->read_buf = kvmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL);
 	if (!sctx->read_buf) {
-		sctx->read_buf = vmalloc(BTRFS_SEND_READ_SIZE);
-		if (!sctx->read_buf) {
-			ret = -ENOMEM;
-			goto out;
-		}
+		ret = -ENOMEM;
+		goto out;
 	}
 
 	sctx->pending_dir_moves = RB_ROOT;
@@ -6396,13 +6390,10 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
 	alloc_size = arg->clone_sources_count * sizeof(*arg->clone_sources);
 
 	if (arg->clone_sources_count) {
-		clone_sources_tmp = kmalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN);
+		clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL);
 		if (!clone_sources_tmp) {
-			clone_sources_tmp = vmalloc(alloc_size);
-			if (!clone_sources_tmp) {
-				ret = -ENOMEM;
-				goto out;
-			}
+			ret = -ENOMEM;
+			goto out;
 		}
 
 		ret = copy_from_user(clone_sources_tmp, arg->clone_sources,