From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 fs/xfs/kmem.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 fs/xfs/kmem.c

(limited to 'fs/xfs/kmem.c')

diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
new file mode 100644
index 000000000..a7a3a63bb
--- /dev/null
+++ b/fs/xfs/kmem.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include <linux/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"
+
+/*
+ * Greedy allocation.  May fail and may return vmalloced memory.
+ */
+void *
+kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize)
+{
+	void		*ptr;
+	size_t		kmsize = maxsize;
+
+	while (!(ptr = vzalloc(kmsize))) {
+		if ((kmsize >>= 1) <= minsize)
+			kmsize = minsize;
+	}
+	if (ptr)
+		*size = kmsize;
+	return ptr;
+}
+
+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,
+		"possible memory allocation deadlock in %s (mode:0x%x)",
+					__func__, lflags);
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+	} while (1);
+}
+
+void *
+kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
+{
+	unsigned noio_flag = 0;
+	void	*ptr;
+	gfp_t	lflags;
+
+	ptr = kmem_zalloc(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_NOIO to prevent memory reclaim re-entering
+	 * the filesystem here and potentially deadlocking.
+	 */
+	if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
+		noio_flag = memalloc_noio_save();
+
+	lflags = kmem_flags_convert(flags);
+	ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
+
+	if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
+		memalloc_noio_restore(noio_flag);
+
+	return ptr;
+}
+
+void *
+kmem_realloc(const void *ptr, size_t newsize, size_t oldsize,
+	     xfs_km_flags_t flags)
+{
+	void	*new;
+
+	new = kmem_alloc(newsize, flags);
+	if (ptr) {
+		if (new)
+			memcpy(new, ptr,
+				((oldsize < newsize) ? oldsize : newsize));
+		kmem_free(ptr);
+	}
+	return new;
+}
+
+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,
+		"possible memory allocation deadlock in %s (mode:0x%x)",
+					__func__, lflags);
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+	} while (1);
+}
-- 
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