v4.19.13 snapshot.
diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
new file mode 100644
index 0000000..fdd9d6e
--- /dev/null
+++ b/fs/xfs/kmem.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include "kmem.h"
+#include "xfs_message.h"
+
+void *
+kmem_alloc(size_t size, xfs_km_flags_t flags)
+{
+ int retries = 0;
+ gfp_t lflags = kmem_flags_convert(flags);
+ void *ptr;
+
+ do {
+ ptr = kmalloc(size, lflags);
+ if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
+ 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);
+}
+
+void *
+kmem_alloc_large(size_t size, xfs_km_flags_t flags)
+{
+ unsigned nofs_flag = 0;
+ void *ptr;
+ gfp_t lflags;
+
+ ptr = kmem_alloc(size, flags | KM_MAYFAIL);
+ if (ptr)
+ return ptr;
+
+ /*
+ * __vmalloc() will allocate data pages and auxillary 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.
+ */
+ if (flags & KM_NOFS)
+ nofs_flag = memalloc_nofs_save();
+
+ lflags = kmem_flags_convert(flags);
+ ptr = __vmalloc(size, lflags, PAGE_KERNEL);
+
+ if (flags & KM_NOFS)
+ memalloc_nofs_restore(nofs_flag);
+
+ return ptr;
+}
+
+void *
+kmem_realloc(const void *old, size_t newsize, xfs_km_flags_t flags)
+{
+ int retries = 0;
+ gfp_t lflags = kmem_flags_convert(flags);
+ void *ptr;
+
+ do {
+ ptr = krealloc(old, newsize, lflags);
+ if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
+ return ptr;
+ if (!(++retries % 100))
+ xfs_err(NULL,
+ "%s(%u) possible memory allocation deadlock size %zu in %s (mode:0x%x)",
+ current->comm, current->pid,
+ newsize, __func__, lflags);
+ congestion_wait(BLK_RW_ASYNC, HZ/50);
+ } while (1);
+}
+
+void *
+kmem_zone_alloc(kmem_zone_t *zone, xfs_km_flags_t flags)
+{
+ int retries = 0;
+ gfp_t lflags = kmem_flags_convert(flags);
+ void *ptr;
+
+ do {
+ ptr = kmem_cache_alloc(zone, lflags);
+ if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
+ return ptr;
+ if (!(++retries % 100))
+ xfs_err(NULL,
+ "%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
+ current->comm, current->pid,
+ __func__, lflags);
+ congestion_wait(BLK_RW_ASYNC, HZ/50);
+ } while (1);
+}