block: always define BIO_MAX_PAGES as 256

Now multi-page bvec can cover CONFIG_THP_SWAP, so we don't need to
increase BIO_MAX_PAGES for it.

CONFIG_THP_SWAP needs to split one THP into normal pages and adds
them all to one bio. With multipage-bvec, it just takes one bvec to
hold them all.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 9f77adcfde823acd4b98a01d94716cdad286ac1b..bdd11d4c2f057aa50d2748b0d36742026659da5e 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -34,15 +34,7 @@
 #define BIO_BUG_ON
 #endif
 
-#ifdef CONFIG_THP_SWAP
-#if HPAGE_PMD_NR > 256
-#define BIO_MAX_PAGES          HPAGE_PMD_NR
-#else
 #define BIO_MAX_PAGES          256
-#endif
-#else
-#define BIO_MAX_PAGES          256
-#endif
 
 #define bio_prio(bio)                  (bio)->bi_ioprio
 #define bio_set_prio(bio, prio)                ((bio)->bi_ioprio = prio)