block: simplify bio_map_kern

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>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250507120451.4000627-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-map.c b/block/blk-map.c
index 6f0bfe66b226528f334b95b5244e9c21c44d0187..23e5d5ebe59eceeceec0ca050de23b47735eae38 100644 (file)
--- 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;
 }