iomap: Convert readahead and readpage to use a folio

Handle folios of arbitrary size instead of working in PAGE_SIZE units.
readahead_folio() decreases the page refcount for you, so this is not
quite a mechanical change.

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

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 2ebea02780b8d80d12ca563a734d68a991303d86..ad89c20cb741bcde4424a9278a3713cc2e9d479e 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -188,8 +188,8 @@ static void iomap_read_end_io(struct bio *bio)
 }
 
 struct iomap_readpage_ctx {
-       struct page             *cur_page;
-       bool                    cur_page_in_bio;
+       struct folio            *cur_folio;
+       bool                    cur_folio_in_bio;
        struct bio              *bio;
        struct readahead_control *rac;
 };
@@ -252,8 +252,7 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
        const struct iomap *iomap = &iter->iomap;
        loff_t pos = iter->pos + offset;
        loff_t length = iomap_length(iter) - offset;
-       struct page *page = ctx->cur_page;
-       struct folio *folio = page_folio(page);
+       struct folio *folio = ctx->cur_folio;
        struct iomap_page *iop;
        loff_t orig_pos = pos;
        size_t poff, plen;
@@ -274,7 +273,7 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
                goto done;
        }
 
-       ctx->cur_page_in_bio = true;
+       ctx->cur_folio_in_bio = true;
        if (iop)
                atomic_add(plen, &iop->read_bytes_pending);
 
@@ -282,7 +281,7 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
        if (!ctx->bio ||
            bio_end_sector(ctx->bio) != sector ||
            !bio_add_folio(ctx->bio, folio, plen, poff)) {
-               gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
+               gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL);
                gfp_t orig_gfp = gfp;
                unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE);
 
@@ -321,30 +320,31 @@ done:
 int
 iomap_readpage(struct page *page, const struct iomap_ops *ops)
 {
+       struct folio *folio = page_folio(page);
        struct iomap_iter iter = {
-               .inode          = page->mapping->host,
-               .pos            = page_offset(page),
-               .len            = PAGE_SIZE,
+               .inode          = folio->mapping->host,
+               .pos            = folio_pos(folio),
+               .len            = folio_size(folio),
        };
        struct iomap_readpage_ctx ctx = {
-               .cur_page       = page,
+               .cur_folio      = folio,
        };
        int ret;
 
-       trace_iomap_readpage(page->mapping->host, 1);
+       trace_iomap_readpage(iter.inode, 1);
 
        while ((ret = iomap_iter(&iter, ops)) > 0)
                iter.processed = iomap_readpage_iter(&iter, &ctx, 0);
 
        if (ret < 0)
-               SetPageError(page);
+               folio_set_error(folio);
 
        if (ctx.bio) {
                submit_bio(ctx.bio);
-               WARN_ON_ONCE(!ctx.cur_page_in_bio);
+               WARN_ON_ONCE(!ctx.cur_folio_in_bio);
        } else {
-               WARN_ON_ONCE(ctx.cur_page_in_bio);
-               unlock_page(page);
+               WARN_ON_ONCE(ctx.cur_folio_in_bio);
+               folio_unlock(folio);
        }
 
        /*
@@ -363,15 +363,15 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
        loff_t done, ret;
 
        for (done = 0; done < length; done += ret) {
-               if (ctx->cur_page && offset_in_page(iter->pos + done) == 0) {
-                       if (!ctx->cur_page_in_bio)
-                               unlock_page(ctx->cur_page);
-                       put_page(ctx->cur_page);
-                       ctx->cur_page = NULL;
+               if (ctx->cur_folio &&
+                   offset_in_folio(ctx->cur_folio, iter->pos + done) == 0) {
+                       if (!ctx->cur_folio_in_bio)
+                               folio_unlock(ctx->cur_folio);
+                       ctx->cur_folio = NULL;
                }
-               if (!ctx->cur_page) {
-                       ctx->cur_page = readahead_page(ctx->rac);
-                       ctx->cur_page_in_bio = false;
+               if (!ctx->cur_folio) {
+                       ctx->cur_folio = readahead_folio(ctx->rac);
+                       ctx->cur_folio_in_bio = false;
                }
                ret = iomap_readpage_iter(iter, ctx, done);
                if (ret <= 0)
@@ -414,10 +414,9 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
 
        if (ctx.bio)
                submit_bio(ctx.bio);
-       if (ctx.cur_page) {
-               if (!ctx.cur_page_in_bio)
-                       unlock_page(ctx.cur_page);
-               put_page(ctx.cur_page);
+       if (ctx.cur_folio) {
+               if (!ctx.cur_folio_in_bio)
+                       folio_unlock(ctx.cur_folio);
        }
 }
 EXPORT_SYMBOL_GPL(iomap_readahead);