[PATCH 16/17] zonefs: use bdev_rw_virt in zonefs_read_super

[Christoph Hellwig]

Switch zonefs_read_super to allocate the superblock buffer using kmalloc
which falls back to the page allocator for PAGE_SIZE allocation but
gives us a kernel virtual address and then use bdev_rw_virt to perform
the synchronous read into it.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 fs/zonefs/super.c | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index faf1eb87895d..d165eb979f21 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -1111,28 +1111,19 @@ static int zonefs_read_super(struct super_block *sb)
        struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
        struct zonefs_super *super;
        u32 crc, stored_crc;
-       struct page *page;
-       struct bio_vec bio_vec;
-       struct bio bio;
        int ret;
 
-       page = alloc_page(GFP_KERNEL);
-       if (!page)
+       super = kmalloc(PAGE_SIZE, GFP_KERNEL);
+       if (!super)
                return -ENOMEM;
 
-       bio_init(&bio, sb->s_bdev, &bio_vec, 1, REQ_OP_READ);
-       bio.bi_iter.bi_sector = 0;
-       __bio_add_page(&bio, page, PAGE_SIZE, 0);
-
-       ret = submit_bio_wait(&bio);
+       ret = bdev_rw_virt(sb->s_bdev, 0, super, PAGE_SIZE, REQ_OP_READ);
        if (ret)
-               goto free_page;
-
-       super = page_address(page);
+               goto free_super;
 
        ret = -EINVAL;
        if (le32_to_cpu(super->s_magic) != ZONEFS_MAGIC)
-               goto free_page;
+               goto free_super;
 
        stored_crc = le32_to_cpu(super->s_crc);
        super->s_crc = 0;
@@ -1140,14 +1131,14 @@ static int zonefs_read_super(struct super_block *sb)
        if (crc != stored_crc) {
                zonefs_err(sb, "Invalid checksum (Expected 0x%08x, got 0x%08x)",
                           crc, stored_crc);
-               goto free_page;
+               goto free_super;
        }
 
        sbi->s_features = le64_to_cpu(super->s_features);
        if (sbi->s_features & ~ZONEFS_F_DEFINED_FEATURES) {
                zonefs_err(sb, "Unknown features set 0x%llx\n",
                           sbi->s_features);
-               goto free_page;
+               goto free_super;
        }
 
        if (sbi->s_features & ZONEFS_F_UID) {
@@ -1155,7 +1146,7 @@ static int zonefs_read_super(struct super_block *sb)
                                       le32_to_cpu(super->s_uid));
                if (!uid_valid(sbi->s_uid)) {
                        zonefs_err(sb, "Invalid UID feature\n");
-                       goto free_page;
+                       goto free_super;
                }
        }
 
@@ -1164,7 +1155,7 @@ static int zonefs_read_super(struct super_block *sb)
                                       le32_to_cpu(super->s_gid));
                if (!gid_valid(sbi->s_gid)) {
                        zonefs_err(sb, "Invalid GID feature\n");
-                       goto free_page;
+                       goto free_super;
                }
        }
 
@@ -1173,15 +1164,14 @@ static int zonefs_read_super(struct super_block *sb)
 
        if (memchr_inv(super->s_reserved, 0, sizeof(super->s_reserved))) {
                zonefs_err(sb, "Reserved area is being used\n");
-               goto free_page;
+               goto free_super;
        }
 
        import_uuid(&sbi->s_uuid, super->s_uuid);
        ret = 0;
 
-free_page:
-       __free_page(page);
-
+free_super:
+       kfree(super);
        return ret;
 }
 
-- 
2.47.2