iomap: switch readahead and readpage to use iomap_iter

Switch the page cache read functions to use iomap_iter instead of
iomap_apply.

Signed-off-by: Christoph Hellwig <hch@lst.de>
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 8418dff..32d8035 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -241,11 +241,12 @@ static inline bool iomap_block_needs_zeroing(struct inode *inode,
                pos >= i_size_read(inode);
 }
 
-static loff_t
-iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-               struct iomap *iomap, struct iomap *srcmap)
+static loff_t iomap_readpage_iter(struct iomap_iter *iter,
+               struct iomap_readpage_ctx *ctx, loff_t offset)
 {
-       struct iomap_readpage_ctx *ctx = data;
+       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 iomap_page *iop;
        loff_t orig_pos = pos;
@@ -253,15 +254,16 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
        sector_t sector;
 
        if (iomap->type == IOMAP_INLINE)
-               return min(iomap_read_inline_data(inode, page, iomap), length);
+               return min(iomap_read_inline_data(iter->inode, page, iomap),
+                                                 length);
 
        /* zero post-eof blocks as the page may be mapped */
-       iop = iomap_page_create(inode, page);
-       iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
+       iop = iomap_page_create(iter->inode, page);
+       iomap_adjust_read_range(iter->inode, iop, &pos, length, &poff, &plen);
        if (plen == 0)
                goto done;
 
-       if (iomap_block_needs_zeroing(inode, iomap, pos)) {
+       if (iomap_block_needs_zeroing(iter->inode, iomap, pos)) {
                zero_user(page, poff, plen);
                iomap_set_range_uptodate(page, poff, plen);
                goto done;
@@ -313,23 +315,23 @@ done:
 int
 iomap_readpage(struct page *page, const struct iomap_ops *ops)
 {
-       struct iomap_readpage_ctx ctx = { .cur_page = page };
-       struct inode *inode = page->mapping->host;
-       unsigned poff;
-       loff_t ret;
+       struct iomap_iter iter = {
+               .inode          = page->mapping->host,
+               .pos            = page_offset(page),
+               .len            = PAGE_SIZE,
+       };
+       struct iomap_readpage_ctx ctx = {
+               .cur_page       = page,
+       };
+       int ret;
 
        trace_iomap_readpage(page->mapping->host, 1);
 
-       for (poff = 0; poff < PAGE_SIZE; poff += ret) {
-               ret = iomap_apply(inode, page_offset(page) + poff,
-                               PAGE_SIZE - poff, 0, ops, &ctx,
-                               iomap_readpage_actor);
-               if (ret <= 0) {
-                       WARN_ON_ONCE(ret == 0);
-                       SetPageError(page);
-                       break;
-               }
-       }
+       while ((ret = iomap_iter(&iter, ops)) > 0)
+               iter.processed = iomap_readpage_iter(&iter, &ctx, 0);
+
+       if (ret < 0)
+               SetPageError(page);
 
        if (ctx.bio) {
                submit_bio(ctx.bio);
@@ -348,15 +350,14 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops)
 }
 EXPORT_SYMBOL_GPL(iomap_readpage);
 
-static loff_t
-iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length,
-               void *data, struct iomap *iomap, struct iomap *srcmap)
+static loff_t iomap_readahead_iter(struct iomap_iter *iter,
+               struct iomap_readpage_ctx *ctx)
 {
-       struct iomap_readpage_ctx *ctx = data;
+       loff_t length = iomap_length(iter);
        loff_t done, ret;
 
        for (done = 0; done < length; done += ret) {
-               if (ctx->cur_page && offset_in_page(pos + done) == 0) {
+               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);
@@ -366,8 +367,7 @@ iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length,
                        ctx->cur_page = readahead_page(ctx->rac);
                        ctx->cur_page_in_bio = false;
                }
-               ret = iomap_readpage_actor(inode, pos + done, length - done,
-                               ctx, iomap, srcmap);
+               ret = iomap_readpage_iter(iter, ctx, done);
        }
 
        return done;
@@ -390,25 +390,19 @@ iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length,
  */
 void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
 {
-       struct inode *inode = rac->mapping->host;
-       loff_t pos = readahead_pos(rac);
-       size_t length = readahead_length(rac);
+       struct iomap_iter iter = {
+               .inode  = rac->mapping->host,
+               .pos    = readahead_pos(rac),
+               .len    = readahead_length(rac),
+       };
        struct iomap_readpage_ctx ctx = {
                .rac    = rac,
        };
 
-       trace_iomap_readahead(inode, readahead_count(rac));
+       trace_iomap_readahead(rac->mapping->host, readahead_count(rac));
 
-       while (length > 0) {
-               ssize_t ret = iomap_apply(inode, pos, length, 0, ops,
-                               &ctx, iomap_readahead_actor);
-               if (ret <= 0) {
-                       WARN_ON_ONCE(ret == 0);
-                       break;
-               }
-               pos += ret;
-               length -= ret;
-       }
+       while (iomap_iter(&iter, ops) > 0)
+               iter.processed = iomap_readahead_iter(&iter, &ctx);
 
        if (ctx.bio)
                submit_bio(ctx.bio);