This adds support for async buffered writes in the mm layer. When the
AOP_FLAG_NOWAIT flag is set, if the page is not already loaded,
the page gets created without blocking on the allocation.
Signed-off-by: Stefan Roesch <shr@xxxxxx>
---
mm/filemap.c | 1 +
mm/folio-compat.c | 12 ++++++++++--
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 5bd692a327d0..f4e2036c5029 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -42,6 +42,7 @@
#include <linux/ramfs.h>
#include <linux/page_idle.h>
#include <linux/migrate.h>
+#include <linux/sched/mm.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include "internal.h"
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 749555a232a8..8243eeb883c1 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -133,11 +133,19 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index, unsigned flags)
{
unsigned fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;
+ gfp_t gfp = mapping_gfp_mask(mapping);
if (flags & AOP_FLAG_NOFS)
fgp_flags |= FGP_NOFS;
- return pagecache_get_page(mapping, index, fgp_flags,
- mapping_gfp_mask(mapping));
+
+ if (flags & AOP_FLAG_NOWAIT) {
+ fgp_flags |= FGP_NOWAIT;
+
+ gfp |= GFP_ATOMIC;
+ gfp &= ~__GFP_DIRECT_RECLAIM;
+ }
+
+ return pagecache_get_page(mapping, index, fgp_flags, gfp);
}
EXPORT_SYMBOL(grab_cache_page_write_begin);
--
2.30.2
