iomap: simplify iomap_readpage_actor

Now that the outstanding reads are counted in bytes, there is no need
to use the low-level __bio_try_merge_page API, we can switch back to
always using bio_add_page and simplify iomap_readpage_actor again.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 87ccb34..712b651 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -241,7 +241,6 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
        struct iomap_readpage_ctx *ctx = data;
        struct page *page = ctx->cur_page;
        struct iomap_page *iop;
-       bool same_page = false, is_contig = false;
        loff_t orig_pos = pos;
        unsigned poff, plen;
        sector_t sector;
@@ -268,16 +267,10 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
        if (iop)
                atomic_add(plen, &iop->read_bytes_pending);
 
-       /* Try to merge into a previous segment if we can */
        sector = iomap_sector(iomap, pos);
-       if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
-               if (__bio_try_merge_page(ctx->bio, page, plen, poff,
-                               &same_page))
-                       goto done;
-               is_contig = true;
-       }
-
-       if (!is_contig || bio_full(ctx->bio, plen)) {
+       if (!ctx->bio ||
+           bio_end_sector(ctx->bio) != sector ||
+           bio_add_page(ctx->bio, page, plen, poff) != plen) {
                gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
                gfp_t orig_gfp = gfp;
                unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE);
@@ -301,9 +294,8 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
                ctx->bio->bi_iter.bi_sector = sector;
                bio_set_dev(ctx->bio, iomap->bdev);
                ctx->bio->bi_end_io = iomap_read_end_io;
+               __bio_add_page(ctx->bio, page, plen, poff);
        }
-
-       bio_add_page(ctx->bio, page, plen, poff);
 done:
        /*
         * Move the caller beyond our range so that it keeps making progress.