[11/19] mm/filemap: Allow PageReadahead to be set on head pages

Commit Message

Matthew Wilcox Oct. 29, 2020, 7:33 p.m. UTC

Adjust the callers to only call PageReadahead on the head page.

Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
---
 include/linux/page-flags.h | 4 ++--
 mm/filemap.c               | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 00d8efd72496..8b523d25fccf 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -380,8 +380,8 @@  PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
 /* PG_readahead is only used for reads; PG_reclaim is only for writes */
 PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
 	TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
-PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
-	TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
+PAGEFLAG(Readahead, reclaim, PF_ONLY_HEAD)
+	TESTCLEARFLAG(Readahead, reclaim, PF_ONLY_HEAD)
 
 #ifdef CONFIG_HIGHMEM
 /*
diff --git a/mm/filemap.c b/mm/filemap.c
index dabc26cf0067..91145e33635d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2892,10 +2892,10 @@  static struct file *do_async_mmap_readahead(struct vm_fault *vmf,
 	mmap_miss = READ_ONCE(ra->mmap_miss);
 	if (mmap_miss)
 		WRITE_ONCE(ra->mmap_miss, --mmap_miss);
-	if (PageReadahead(page)) {
+	if (PageReadahead(thp_head(page))) {
 		fpin = maybe_unlock_mmap_for_io(vmf, fpin);
 		page_cache_async_readahead(mapping, ra, file,
-					   page, offset, ra->ra_pages);
+				thp_head(page), offset, ra->ra_pages);
 	}
 	return fpin;
 }