iomap: move bio read logic into helper function

Move the iomap_readpage_iter() bio read logic into a separate helper
function, iomap_bio_read_folio_range(). This is needed to make iomap
read/readahead more generically usable, especially for filesystems that
do not require CONFIG_BLOCK.

Additionally rename buffered write's iomap_read_folio_range() function
to iomap_bio_read_folio_range_sync() to better describe its synchronous
behavior.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 9535733ed07a2f85b15d2dfc67d021f24dbe10cb..7e65075b63451e91117a4e00905ce8f7bb6b2d70 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -367,36 +367,15 @@ struct iomap_readpage_ctx {
        struct readahead_control *rac;
 };
 
-static int iomap_readpage_iter(struct iomap_iter *iter,
-               struct iomap_readpage_ctx *ctx)
+static void iomap_bio_read_folio_range(const struct iomap_iter *iter,
+               struct iomap_readpage_ctx *ctx, loff_t pos, size_t plen)
 {
+       struct folio *folio = ctx->cur_folio;
        const struct iomap *iomap = &iter->iomap;
-       loff_t pos = iter->pos;
+       struct iomap_folio_state *ifs = folio->private;
+       size_t poff = offset_in_folio(folio, pos);
        loff_t length = iomap_length(iter);
-       struct folio *folio = ctx->cur_folio;
-       struct iomap_folio_state *ifs;
-       size_t poff, plen;
        sector_t sector;
-       int ret;
-
-       if (iomap->type == IOMAP_INLINE) {
-               ret = iomap_read_inline_data(iter, folio);
-               if (ret)
-                       return ret;
-               return iomap_iter_advance(iter, length);
-       }
-
-       /* zero post-eof blocks as the page may be mapped */
-       ifs = ifs_alloc(iter->inode, folio, iter->flags);
-       iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff, &plen);
-       if (plen == 0)
-               goto done;
-
-       if (iomap_block_needs_zeroing(iter, pos)) {
-               folio_zero_range(folio, poff, plen);
-               iomap_set_range_uptodate(folio, poff, plen);
-               goto done;
-       }
 
        ctx->cur_folio_in_bio = true;
        if (ifs) {
@@ -435,6 +414,37 @@ static int iomap_readpage_iter(struct iomap_iter *iter,
                ctx->bio->bi_end_io = iomap_read_end_io;
                bio_add_folio_nofail(ctx->bio, folio, plen, poff);
        }
+}
+
+static int iomap_readpage_iter(struct iomap_iter *iter,
+               struct iomap_readpage_ctx *ctx)
+{
+       const struct iomap *iomap = &iter->iomap;
+       loff_t pos = iter->pos;
+       loff_t length = iomap_length(iter);
+       struct folio *folio = ctx->cur_folio;
+       size_t poff, plen;
+       int ret;
+
+       if (iomap->type == IOMAP_INLINE) {
+               ret = iomap_read_inline_data(iter, folio);
+               if (ret)
+                       return ret;
+               return iomap_iter_advance(iter, length);
+       }
+
+       /* zero post-eof blocks as the page may be mapped */
+       ifs_alloc(iter->inode, folio, iter->flags);
+       iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff, &plen);
+       if (plen == 0)
+               goto done;
+
+       if (iomap_block_needs_zeroing(iter, pos)) {
+               folio_zero_range(folio, poff, plen);
+               iomap_set_range_uptodate(folio, poff, plen);
+       } else {
+               iomap_bio_read_folio_range(iter, ctx, pos, plen);
+       }
 
 done:
        /*
@@ -559,7 +569,7 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
 }
 EXPORT_SYMBOL_GPL(iomap_readahead);
 
-static int iomap_read_folio_range(const struct iomap_iter *iter,
+static int iomap_bio_read_folio_range_sync(const struct iomap_iter *iter,
                struct folio *folio, loff_t pos, size_t len)
 {
        const struct iomap *srcmap = iomap_iter_srcmap(iter);
@@ -572,7 +582,7 @@ static int iomap_read_folio_range(const struct iomap_iter *iter,
        return submit_bio_wait(&bio);
 }
 #else
-static int iomap_read_folio_range(const struct iomap_iter *iter,
+static int iomap_bio_read_folio_range_sync(const struct iomap_iter *iter,
                struct folio *folio, loff_t pos, size_t len)
 {
        WARN_ON_ONCE(1);
@@ -749,7 +759,7 @@ static int __iomap_write_begin(const struct iomap_iter *iter,
                                status = write_ops->read_folio_range(iter,
                                                folio, block_start, plen);
                        else
-                               status = iomap_read_folio_range(iter,
+                               status = iomap_bio_read_folio_range_sync(iter,
                                                folio, block_start, plen);
                        if (status)
                                return status;