btrfs: sink gfp parameter to btrfs_io_bio_alloc

We can hardcode GFP_NOFS to btrfs_io_bio_alloc, although it means we
change it back from GFP_KERNEL in scrub. I'd rather save a few stack
bytes from not passing the gfp flags in the remaining, more imporatant,
contexts and the bio allocating API now looks more consistent.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 1e2dfea..58a249c 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1737,7 +1737,7 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 		}
 
 		WARN_ON(!page->page);
-		bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
+		bio = btrfs_io_bio_alloc(1);
 		bio->bi_bdev = page->dev->bdev;
 
 		bio_add_page(bio, page->page, PAGE_SIZE, 0);
@@ -1825,7 +1825,7 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 			return -EIO;
 		}
 
-		bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
+		bio = btrfs_io_bio_alloc(1);
 		bio->bi_bdev = page_bad->dev->bdev;
 		bio->bi_iter.bi_sector = page_bad->physical >> 9;
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
@@ -1915,8 +1915,7 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 		sbio->dev = sctx->wr_tgtdev;
 		bio = sbio->bio;
 		if (!bio) {
-			bio = btrfs_io_bio_alloc(GFP_KERNEL,
-					sctx->pages_per_wr_bio);
+			bio = btrfs_io_bio_alloc(sctx->pages_per_wr_bio);
 			sbio->bio = bio;
 		}
 
@@ -2316,8 +2315,7 @@ static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
 		sbio->dev = spage->dev;
 		bio = sbio->bio;
 		if (!bio) {
-			bio = btrfs_io_bio_alloc(GFP_KERNEL,
-					sctx->pages_per_rd_bio);
+			bio = btrfs_io_bio_alloc(sctx->pages_per_rd_bio);
 			sbio->bio = bio;
 		}
 
@@ -2443,7 +2441,7 @@ static void scrub_missing_raid56_pages(struct scrub_block *sblock)
 		goto bbio_out;
 	}
 
-	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
+	bio = btrfs_io_bio_alloc(0);
 	bio->bi_iter.bi_sector = logical >> 9;
 	bio->bi_private = sblock;
 	bio->bi_end_io = scrub_missing_raid56_end_io;
@@ -3019,7 +3017,7 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
 	if (ret || !bbio || !bbio->raid_map)
 		goto bbio_out;
 
-	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
+	bio = btrfs_io_bio_alloc(0);
 	bio->bi_iter.bi_sector = sparity->logic_start >> 9;
 	bio->bi_private = sparity;
 	bio->bi_end_io = scrub_parity_bio_endio;
@@ -4626,7 +4624,7 @@ static int write_page_nocow(struct scrub_ctx *sctx,
 			"scrub write_page_nocow(bdev == NULL) is unexpected");
 		return -EIO;
 	}
-	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
+	bio = btrfs_io_bio_alloc(1);
 	bio->bi_iter.bi_size = 0;
 	bio->bi_iter.bi_sector = physical_for_dev_replace >> 9;
 	bio->bi_bdev = dev->bdev;