[PATCH v2 2/4] btrfs: make btrfs_alloc_subpage() to return struct btrfs_subpage * directly
From: Qu Wenruo <hidden>
Date: 2021-08-17 09:39:04
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
The existing calling convention of btrfs_alloc_subpage() is pretty awful. Change it to a more common pattern by returning struct btrfs_subpage * directly and let the caller to determine if the call succeeded. Signed-off-by: Qu Wenruo <redacted> --- fs/btrfs/extent_io.c | 7 ++++--- fs/btrfs/subpage.c | 33 +++++++++++++++++++-------------- fs/btrfs/subpage.h | 5 ++--- 3 files changed, 25 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 19889dbfcf15..3c5770d47a95 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c@@ -6138,9 +6138,10 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, * support, so we still preallocate the memory in the loop. */ if (fs_info->sectorsize < PAGE_SIZE) { - ret = btrfs_alloc_subpage(fs_info, &prealloc, - BTRFS_SUBPAGE_METADATA); - if (ret < 0) { + prealloc = btrfs_alloc_subpage(fs_info, + BTRFS_SUBPAGE_METADATA); + if (IS_ERR(prealloc)) { + ret = PTR_ERR(prealloc); unlock_page(p); put_page(p); exists = ERR_PTR(ret);
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index ff1c6ba34a4d..ae6c68370a95 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c@@ -66,7 +66,7 @@ int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, struct page *page, enum btrfs_subpage_type type) { - struct btrfs_subpage *subpage = NULL; + struct btrfs_subpage *subpage; int ret; /*
@@ -75,13 +75,16 @@ int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, */ if (page->mapping) ASSERT(PageLocked(page)); + /* Either not subpage, or the page already has private attached */ if (fs_info->sectorsize == PAGE_SIZE || PagePrivate(page)) return 0; - ret = btrfs_alloc_subpage(fs_info, &subpage, type); - if (ret < 0) + subpage = btrfs_alloc_subpage(fs_info, type); + if (IS_ERR(subpage)) { + ret = PTR_ERR(subpage); return ret; + } attach_page_private(page, subpage); return 0; }
@@ -100,23 +103,25 @@ void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, btrfs_free_subpage(subpage); } -int btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, - struct btrfs_subpage **ret, - enum btrfs_subpage_type type) +struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, + enum btrfs_subpage_type type) { + struct btrfs_subpage *ret; + ASSERT(fs_info->sectorsize < PAGE_SIZE); - *ret = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS); - if (!*ret) - return -ENOMEM; - spin_lock_init(&(*ret)->lock); + ret = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS); + if (!ret) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&ret->lock); if (type == BTRFS_SUBPAGE_METADATA) { - atomic_set(&(*ret)->eb_refs, 0); + atomic_set(&ret->eb_refs, 0); } else { - atomic_set(&(*ret)->readers, 0); - atomic_set(&(*ret)->writers, 0); + atomic_set(&ret->readers, 0); + atomic_set(&ret->writers, 0); } - return 0; + return ret; } void btrfs_free_subpage(struct btrfs_subpage *subpage)
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 0120948f37a1..fdcadc5193c1 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h@@ -59,9 +59,8 @@ void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct page *page); /* Allocate additional data where page represents more than one sector */ -int btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, - struct btrfs_subpage **ret, - enum btrfs_subpage_type type); +struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, + enum btrfs_subpage_type type); void btrfs_free_subpage(struct btrfs_subpage *subpage); void btrfs_page_inc_eb_refs(const struct btrfs_fs_info *fs_info,
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2.32.0