1 files changed, 95 insertions, 0 deletions
diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
new file mode 100644
index 000000000..e986b95d9
--- /dev/null
+++ b/fs/xfs/kmem.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include <linux/backing-dev.h>
+#include "xfs_message.h"
+#include "xfs_trace.h"
+
+void *
+kmem_alloc(size_t size, xfs_km_flags_t flags)
+{
+	int	retries = 0;
+	gfp_t	lflags = kmem_flags_convert(flags);
+	void	*ptr;
+
+	trace_kmem_alloc(size, flags, _RET_IP_);
+
+	do {
+		ptr = kmalloc(size, lflags);
+		if (ptr || (flags & KM_MAYFAIL))
+			return ptr;
+		if (!(++retries % 100))
+			xfs_err(NULL,
+	"%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)",
+				current->comm, current->pid,
+				(unsigned int)size, __func__, lflags);
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+	} while (1);
+}
+
+
+/*
+ * __vmalloc() will allocate data pages and auxiliary structures (e.g.
+ * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context here. Hence
+ * we need to tell memory reclaim that we are in such a context via
+ * PF_MEMALLOC_NOFS to prevent memory reclaim re-entering the filesystem here
+ * and potentially deadlocking.
+ */
+static void *
+__kmem_vmalloc(size_t size, xfs_km_flags_t flags)
+{
+	unsigned nofs_flag = 0;
+	void	*ptr;
+	gfp_t	lflags = kmem_flags_convert(flags);
+
+	if (flags & KM_NOFS)
+		nofs_flag = memalloc_nofs_save();
+
+	ptr = __vmalloc(size, lflags);
+
+	if (flags & KM_NOFS)
+		memalloc_nofs_restore(nofs_flag);
+
+	return ptr;
+}
+
+/*
+ * Same as kmem_alloc_large, except we guarantee the buffer returned is aligned
+ * to the @align_mask. We only guarantee alignment up to page size, we'll clamp
+ * alignment at page size if it is larger. vmalloc always returns a PAGE_SIZE
+ * aligned region.
+ */
+void *
+kmem_alloc_io(size_t size, int align_mask, xfs_km_flags_t flags)
+{
+	void	*ptr;
+
+	trace_kmem_alloc_io(size, flags, _RET_IP_);
+
+	if (WARN_ON_ONCE(align_mask >= PAGE_SIZE))
+		align_mask = PAGE_SIZE - 1;
+
+	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
+	if (ptr) {
+		if (!((uintptr_t)ptr & align_mask))
+			return ptr;
+		kfree(ptr);
+	}
+	return __kmem_vmalloc(size, flags);
+}
+
+void *
+kmem_alloc_large(size_t size, xfs_km_flags_t flags)
+{
+	void	*ptr;
+
+	trace_kmem_alloc_large(size, flags, _RET_IP_);
+
+	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
+	if (ptr)
+		return ptr;
+	return __kmem_vmalloc(size, flags);
+}