[PATCHv3 19/41] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if huge page cache enabled

[Kirill A. Shutemov]

We are going to do IO a huge page a time. So we need BIO_MAX_PAGES to be
at least HPAGE_PMD_NR. For x86-64, it's 512 pages.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 include/linux/bio.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 23ddf4b46a9b..ebf4f312a642 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -40,7 +40,11 @@
 #define BIO_BUG_ON
 #endif
 
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+#define BIO_MAX_PAGES		(HPAGE_PMD_NR > 256 ? HPAGE_PMD_NR : 256)
+#else
 #define BIO_MAX_PAGES		256
+#endif
 
 #define bio_prio(bio)			(bio)->bi_ioprio
 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
-- 
2.9.3