[PATCH 08/12] swap,iomap: simplify iomap_swapfile_iter

[Christoph Hellwig <hch@lst.de>]

add_swap_extent already coalesces multiple extents, no need to duplicate
that in the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/iomap/swapfile.c | 104 +++++++++++++-------------------------------
 1 file changed, 31 insertions(+), 73 deletions(-)

diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c
index cf354fdfb7c3..a4e0ca462cc4 100644
--- a/fs/iomap/swapfile.c
+++ b/fs/iomap/swapfile.c
@@ -6,57 +6,32 @@
 #include <linux/iomap.h>
 #include <linux/swap.h>
 
-/* Swapfile activation */
-
-struct iomap_swapfile_info {
-	struct iomap iomap;		/* accumulated iomap */
-	struct swap_info_struct *sis;
-	unsigned long nr_pages;		/* number of pages collected */
-	struct file *file;
-};
-
-/*
- * Collect physical extents for this swap file.  Physical extents reported to
- * the swap code must be trimmed to align to a page boundary.  The logical
- * offset within the file is irrelevant since the swapfile code maps logical
- * page numbers of the swap device to the physical page-aligned extents.
- */
-static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
-{
-	struct iomap *iomap = &isi->iomap;
-	uint64_t first_ppage;
-	uint64_t next_ppage;
-
-	/*
-	 * Round the start up and the end down so that the physical
-	 * extent aligns to a page boundary.
-	 */
-	first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
-	next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
-			PAGE_SHIFT;
-	return add_swap_extent(isi->sis, next_ppage - first_ppage, first_ppage);
-}
-
-static int iomap_swapfile_fail(struct iomap_swapfile_info *isi, const char *str)
+static int iomap_swapfile_fail(struct file *file, const char *str)
 {
 	char *buf, *p = ERR_PTR(-ENOMEM);
 
 	buf = kmalloc(PATH_MAX, GFP_KERNEL);
 	if (buf)
-		p = file_path(isi->file, buf, PATH_MAX);
+		p = file_path(file, buf, PATH_MAX);
 	pr_err("swapon: file %s %s\n", IS_ERR(p) ? "<unknown>" : p, str);
 	kfree(buf);
 	return -EINVAL;
 }
 
 /*
- * Accumulate iomaps for this swap file.  We have to accumulate iomaps because
- * swap only cares about contiguous page-aligned physical extents and makes no
- * distinction between written and unwritten extents.
+ * Report physical extents for this swap file.  Physical extents reported to the
+ * swap code must be trimmed to align to a page boundary.  The logical offset
+ * within the file is irrelevant since the swapfile code maps logical page
+ * numbers of the swap device to the physical page-aligned extents.
  */
-static int iomap_swapfile_iter(struct iomap_iter *iter,
-		struct iomap *iomap, struct iomap_swapfile_info *isi)
+static int iomap_swapfile_iter(struct iomap_iter *iter, struct file *file,
+		struct swap_info_struct *sis)
 {
+	struct iomap *iomap = &iter->iomap;
+	uint64_t first_ppage;
+	uint64_t next_ppage;
+	int error;
+
 	switch (iomap->type) {
 	case IOMAP_MAPPED:
 	case IOMAP_UNWRITTEN:
@@ -64,35 +39,31 @@ static int iomap_swapfile_iter(struct iomap_iter *iter,
 		break;
 	case IOMAP_INLINE:
 		/* No inline data. */
-		return iomap_swapfile_fail(isi, "is inline");
+		return iomap_swapfile_fail(file, "is inline");
 	default:
-		return iomap_swapfile_fail(isi, "has unallocated extents");
+		return iomap_swapfile_fail(file, "has unallocated extents");
 	}
 
 	/* No uncommitted metadata or shared blocks. */
 	if (iomap->flags & IOMAP_F_DIRTY)
-		return iomap_swapfile_fail(isi, "is not committed");
+		return iomap_swapfile_fail(file, "is not committed");
 	if (iomap->flags & IOMAP_F_SHARED)
-		return iomap_swapfile_fail(isi, "has shared extents");
+		return iomap_swapfile_fail(file, "has shared extents");
 
 	/* Only one bdev per swap file. */
-	if (iomap->bdev != isi->sis->bdev)
-		return iomap_swapfile_fail(isi, "outside the main device");
-
-	if (isi->iomap.length == 0) {
-		/* No accumulated extent, so just store it. */
-		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
-	} else if (isi->iomap.addr + isi->iomap.length == iomap->addr) {
-		/* Append this to the accumulated extent. */
-		isi->iomap.length += iomap->length;
-	} else {
-		/* Otherwise, add the retained iomap and store this one. */
-		int error = iomap_swapfile_add_extent(isi);
-		if (error)
-			return error;
-		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
-	}
+	if (iomap->bdev != sis->bdev)
+		return iomap_swapfile_fail(file, "outside the main device");
 
+	/*
+	 * Round the start up and the end down so that the physical extent
+	 * aligns to a page boundary.
+	 */
+	first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
+	next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
+			PAGE_SHIFT;
+	error = add_swap_extent(sis, next_ppage - first_ppage, first_ppage);
+	if (error)
+		return error;
 	return iomap_iter_advance_full(iter);
 }
 
@@ -110,10 +81,6 @@ int iomap_swap_activate(struct file *file, struct swap_info_struct *sis,
 		.len	= ALIGN_DOWN(i_size_read(inode), PAGE_SIZE),
 		.flags	= IOMAP_REPORT,
 	};
-	struct iomap_swapfile_info isi = {
-		.sis = sis,
-		.file = file,
-	};
 	int ret;
 
 	/*
@@ -125,16 +92,7 @@ int iomap_swap_activate(struct file *file, struct swap_info_struct *sis,
 		return ret;
 
 	while ((ret = iomap_iter(&iter, ops)) > 0)
-		iter.status = iomap_swapfile_iter(&iter, &iter.iomap, &isi);
-	if (ret < 0)
-		return ret;
-
-	if (isi.iomap.length) {
-		ret = iomap_swapfile_add_extent(&isi);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
+		iter.status = iomap_swapfile_iter(&iter, file, sis);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(iomap_swap_activate);
-- 
2.53.0