[Concept,06/19] linux: Add bio.h header with block I/O stubs

diff --git a/fs/ext4l/ext4_uboot.h b/fs/ext4l/ext4_uboot.h
index 40c68085c7a..b49e6604589 100644
--- a/fs/ext4l/ext4_uboot.h
+++ b/fs/ext4l/ext4_uboot.h
@@ -1972,60 +1972,9 @@  static inline unsigned long ext4_find_next_bit_le(const void *addr,
 	({ (void)(bdev); 0U; })
 
 /*
- * Stubs for page-io.c
+ * Stubs for page-io.c - bio types are in linux/bio.h
  */
-
-/* bio_vec - segment in a bio */
-struct bio_vec {
-	struct page *bv_page;
-	unsigned int bv_len;
-	unsigned int bv_offset;
-};
-
-/* bvec_iter - iterator for bio_vec */
-struct bvec_iter {
-	sector_t bi_sector;
-	unsigned int bi_size;
-	unsigned int bi_idx;
-	unsigned int bi_bvec_done;
-};
-
-/* bio - block I/O structure */
-struct bio {
-	struct bio *bi_next;
-	struct block_device *bi_bdev;
-	unsigned long bi_opf;
-	unsigned short bi_flags;
-	unsigned short bi_ioprio;
-	unsigned short bi_write_hint;
-	int bi_status;
-	struct bvec_iter bi_iter;
-	atomic_t __bi_remaining;
-	void *bi_private;
-	void (*bi_end_io)(struct bio *);
-};
-
-/* bio_sectors - return number of sectors in bio */
-static inline unsigned int bio_sectors(struct bio *bio)
-{
-	return bio->bi_iter.bi_size >> 9;
-}
-
-/* folio_iter for bio iteration */
-struct folio_iter {
-	int i;
-	struct folio *folio;
-	size_t offset;
-	size_t length;
-};
-
-/* bio operations - stubs */
-#define bio_for_each_folio_all(fi, bio) \
-	for ((fi).i = 0; (fi).i < 0; (fi).i++)
-#define bio_put(bio)			free(bio)
-#define bio_alloc(bdev, vecs, op, gfp)	((struct bio *)calloc(1, sizeof(struct bio)))
-#define submit_bio(bio)			do { } while (0)
-#define BIO_MAX_VECS			256
+#include <linux/bio.h>
 
 /* refcount operations - map to atomic */
 #define refcount_set(r, v)		atomic_set((atomic_t *)(r), v)
@@ -2037,12 +1986,6 @@  struct folio_iter {
 
 /* printk_ratelimited is in linux/printk.h */
 
-/* mapping_set_error - record error in address_space */
-#define mapping_set_error(m, e)		do { (void)(m); (void)(e); } while (0)
-
-/* blk_status_to_errno - convert block status to errno */
-#define blk_status_to_errno(status)	(-(status))
-
 /* atomic_inc is in asm-generic/atomic.h */
 /* GFP_NOIO is in linux/slab.h */
 
@@ -2059,9 +2002,7 @@  bool __folio_start_writeback(struct folio *folio, bool keep_write);
 #define wbc_account_cgroup_owner(wbc, folio, bytes) \
 	do { (void)(wbc); (void)(folio); (void)(bytes); } while (0)
 
-/* bio operations */
-#define bio_add_folio(bio, folio, len, off) \
-	({ (void)(bio); (void)(folio); (void)(len); (void)(off); 1; })
+/* bio_add_folio is in linux/bio.h */
 
 /*
  * Stubs for readpage.c
diff --git a/include/linux/bio.h b/include/linux/bio.h
new file mode 100644
index 00000000000..d8a955dba12
--- /dev/null
+++ b/include/linux/bio.h
@@ -0,0 +1,117 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Block I/O structures stub for U-Boot
+ *
+ * U-Boot doesn't have a real block I/O layer, so these are stubs.
+ */
+#ifndef __LINUX_BIO_H
+#define __LINUX_BIO_H
+
+#include <linux/types.h>
+#include <malloc.h>
+
+/* Forward declarations */
+struct block_device;
+struct page;
+struct folio;
+
+/**
+ * struct bio_vec - segment in a bio
+ * @bv_page: page containing the data
+ * @bv_len: length of the segment
+ * @bv_offset: offset within the page
+ */
+struct bio_vec {
+	struct page *bv_page;
+	unsigned int bv_len;
+	unsigned int bv_offset;
+};
+
+/**
+ * struct bvec_iter - iterator for bio_vec
+ * @bi_sector: current sector
+ * @bi_size: remaining size
+ * @bi_idx: current index into bio_vec array
+ * @bi_bvec_done: bytes completed in current bvec
+ */
+struct bvec_iter {
+	sector_t bi_sector;
+	unsigned int bi_size;
+	unsigned int bi_idx;
+	unsigned int bi_bvec_done;
+};
+
+/**
+ * struct bio - block I/O structure
+ * @bi_next: next bio in chain
+ * @bi_bdev: target block device
+ * @bi_opf: operation and flags
+ * @bi_flags: bio flags
+ * @bi_ioprio: I/O priority
+ * @bi_write_hint: write lifetime hint
+ * @bi_status: completion status
+ * @bi_iter: current position iterator
+ * @__bi_remaining: remaining count for chained bios
+ * @bi_private: private data for completion
+ * @bi_end_io: completion callback
+ *
+ * U-Boot stub.
+ */
+struct bio {
+	struct bio *bi_next;
+	struct block_device *bi_bdev;
+	unsigned long bi_opf;
+	unsigned short bi_flags;
+	unsigned short bi_ioprio;
+	unsigned short bi_write_hint;
+	int bi_status;
+	struct bvec_iter bi_iter;
+	atomic_t __bi_remaining;
+	void *bi_private;
+	void (*bi_end_io)(struct bio *);
+};
+
+/**
+ * bio_sectors() - return number of sectors in bio
+ * @bio: bio to query
+ *
+ * Return: number of 512-byte sectors
+ */
+static inline unsigned int bio_sectors(struct bio *bio)
+{
+	return bio->bi_iter.bi_size >> 9;
+}
+
+/**
+ * struct folio_iter - iterator for folio iteration over bio
+ * @i: current index
+ * @folio: current folio
+ * @offset: offset within folio
+ * @length: length of current segment
+ */
+struct folio_iter {
+	int i;
+	struct folio *folio;
+	size_t offset;
+	size_t length;
+};
+
+/* Maximum number of bio_vecs */
+#define BIO_MAX_VECS		256
+
+/* bio operations - stubs */
+#define bio_for_each_folio_all(fi, bio) \
+	for ((fi).i = 0; (fi).i < 0; (fi).i++)
+#define bio_put(bio)			free(bio)
+#define bio_alloc(bdev, vecs, op, gfp)	((struct bio *)calloc(1, sizeof(struct bio)))
+#define submit_bio(bio)			do { } while (0)
+#define bio_add_folio(bio, folio, len, off) \
+	({ (void)(bio); (void)(folio); (void)(len); (void)(off); 1; })
+
+/* blk_status_to_errno - convert block status to errno */
+#define blk_status_to_errno(status)	(-(status))
+
+/* mapping_set_error - record error in address_space */
+#define mapping_set_error(m, e)		do { (void)(m); (void)(e); } while (0)
+
+#endif /* __LINUX_BIO_H */