[PATCH 07/19] block: simplify bio_map_kern

Christoph Hellwig
2025-04-30T21:22:21Z

Rewrite bio_map_kern using the new bio_add_* helpers and drop the
kerneldoc comment that is superfluous for an internal helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-map.c | 56 ++++++++-----------------------------------------
1 file changed, 9 insertions(+), 47 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index ca6b55ac0da1..0bc823b168e4 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -317,64 +317,26 @@ static void bio_map_kern_endio(struct bio *bio)
kfree(bio);
}

-/**
- * bio_map_kern - map kernel address into bio
- * @data: pointer to buffer to map
- * @len: length in bytes
- * @op: bio/request operation
- * @gfp_mask: allocation flags for bio allocation
- *
- * Map the kernel address into a bio suitable for io to a block
- * device. Returns an error pointer in case of error.
- */
-static struct bio *bio_map_kern(void *data, unsigned int len,
- enum req_op op, gfp_t gfp_mask)
+static struct bio *bio_map_kern(void *data, unsigned int len, enum req_op op,
+ gfp_t gfp_mask)
{
- unsigned long kaddr = (unsigned long)data;
- unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
- unsigned long start = kaddr >> PAGE_SHIFT;
- const int nr_pages = end - start;
- bool is_vmalloc = is_vmalloc_addr(data);
- struct page *page;
- int offset, i;
+ unsigned int nr_vecs = bio_add_max_vecs(data, len);
struct bio *bio;

- bio = bio_kmalloc(nr_pages, gfp_mask);
+ bio = bio_kmalloc(nr_vecs, gfp_mask);
if (!bio)
return ERR_PTR(-ENOMEM);
- bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, op);
-
- if (is_vmalloc) {
- flush_kernel_vmap_range(data, len);
+ bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs, op);
+ if (is_vmalloc_addr(data)) {
bio->bi_private = data;
- }
-
- offset = offset_in_page(kaddr);
- for (i = 0; i < nr_pages; i++) {
- unsigned int bytes = PAGE_SIZE - offset;
-
- if (len <= 0)
- break;
-
- if (bytes > len)
- bytes = len;
-
- if (!is_vmalloc)
- page = virt_to_page(data);
- else
- page = vmalloc_to_page(data);
- if (bio_add_page(bio, page, bytes, offset) < bytes) {
- /* we don't support partial mappings */
+ if (!bio_add_vmalloc(bio, data, len)) {
bio_uninit(bio);
kfree(bio);
return ERR_PTR(-EINVAL);
}
-
- data += bytes;
- len -= bytes;
- offset = 0;
+ } else {
+ bio_add_virt_nofail(bio, data, len);
}
-
bio->bi_end_io = bio_map_kern_endio;
return bio;
}
--
2.47.2