From 4275f6e6e56437d41d021833437add74ec22db87 Mon Sep 17 00:00:00 2001
From: Zach Brown <zab@versity.com>
Date: Mon, 1 Aug 2022 09:25:17 -0700
Subject: [PATCH] Use memalloc_nofs_save

memalloc_nofs_save() was introduced as preferential to trying to use GFP
flags to indicate that a task should not recurse during reclaim.  We use
it instead of the _noio_ we were using before.

Signed-off-by: Zach Brown <zab@versity.com>
---
 kmod/src/Makefile.kernelcompat | 9 +++++++++
 kmod/src/block.c               | 7 ++++---
 kmod/src/kernelcompat.h        | 5 +++++
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/kmod/src/Makefile.kernelcompat b/kmod/src/Makefile.kernelcompat
index 3e129eed..fb802bf2 100644
--- a/kmod/src/Makefile.kernelcompat
+++ b/kmod/src/Makefile.kernelcompat
@@ -101,3 +101,12 @@ endif
 ifneq (,$(shell grep 'percpu_counter_add_batch' include/linux/percpu_counter.h))
 ccflags-y += -DKC_PERCPU_COUNTER_ADD_BATCH
 endif
+
+#
+# v4.11-4550-g7dea19f9ee63
+#
+# Introduced memalloc_nofs_{save,restore} preferred instead of _noio_.
+#
+ifneq (,$(shell grep 'memalloc_nofs_save' include/linux/sched/mm.h))
+ccflags-y += -DKC_MEMALLOC_NOFS_SAVE
+endif
diff --git a/kmod/src/block.c b/kmod/src/block.c
index 89cda9c0..14686f15 100644
--- a/kmod/src/block.c
+++ b/kmod/src/block.c
@@ -21,6 +21,7 @@
 #include <linux/blkdev.h>
 #include <linux/rhashtable.h>
 #include <linux/random.h>
+#include <linux/sched/mm.h>
 
 #include "format.h"
 #include "super.h"
@@ -128,7 +129,7 @@ static __le32 block_calc_crc(struct scoutfs_block_header *hdr, u32 size)
 static struct block_private *block_alloc(struct super_block *sb, u64 blkno)
 {
 	struct block_private *bp;
-	unsigned int noio_flags;
+	unsigned int nofs_flags;
 
 	/*
 	 * If we had multiple blocks per page we'd need to be a little
@@ -156,9 +157,9 @@ static struct block_private *block_alloc(struct super_block *sb, u64 blkno)
 		 * spurious reclaim-on dependencies and warnings.
 		 */
 		lockdep_off();
-		noio_flags = memalloc_noio_save();
+		nofs_flags = memalloc_nofs_save();
 		bp->virt = __vmalloc(SCOUTFS_BLOCK_LG_SIZE, GFP_NOFS | __GFP_HIGHMEM, PAGE_KERNEL);
-		memalloc_noio_restore(noio_flags);
+		memalloc_nofs_restore(nofs_flags);
 		lockdep_on();
 
 		if (!bp->virt) {
diff --git a/kmod/src/kernelcompat.h b/kmod/src/kernelcompat.h
index b22b265f..4923730e 100644
--- a/kmod/src/kernelcompat.h
+++ b/kmod/src/kernelcompat.h
@@ -117,4 +117,9 @@ static inline int dir_emit_dots(struct file *file, void *dirent,
 #define percpu_counter_add_batch __percpu_counter_add
 #endif
 
+#ifndef KC_MEMALLOC_NOFS_SAVE
+#define memalloc_nofs_save memalloc_noio_save
+#define memalloc_nofs_restore memalloc_noio_restore
+#endif
+
 #endif