btrfs: provide btrfs_page_clamp_*() helpers
In the coming subpage RW supports, there are a lot of page status update
calls which need to be converted to subpage compatible version, which
needs @start and @len.
Some call sites already have such @start/@len and are already in
page range, like various endio functions.
But there are also call sites which need to clamp the range for subpage
case, like btrfs_dirty_pagse() and __process_contig_pages().
Here we introduce new helpers, btrfs_page_clamp_*(), to do and only do the
clamp for subpage version.
Although in theory all existing btrfs_page_*() calls can be converted to
use btrfs_page_clamp_*() directly, but that would make us to do
unnecessary clamp operations.
Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64]
Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64]
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index 2d19089..a6cf177 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -354,6 +354,16 @@ void btrfs_subpage_clear_writeback(const struct btrfs_fs_info *fs_info,
spin_unlock_irqrestore(&subpage->lock, flags);
}
+static void btrfs_subpage_clamp_range(struct page *page, u64 *start, u32 *len)
+{
+ u64 orig_start = *start;
+ u32 orig_len = *len;
+
+ *start = max_t(u64, page_offset(page), orig_start);
+ *len = min_t(u64, page_offset(page) + PAGE_SIZE,
+ orig_start + orig_len) - *start;
+}
+
/*
* Unlike set/clear which is dependent on each page status, for test all bits
* are tested in the same way.
@@ -408,6 +418,34 @@ bool btrfs_page_test_##name(const struct btrfs_fs_info *fs_info, \
if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) \
return test_page_func(page); \
return btrfs_subpage_test_##name(fs_info, page, start, len); \
+} \
+void btrfs_page_clamp_set_##name(const struct btrfs_fs_info *fs_info, \
+ struct page *page, u64 start, u32 len) \
+{ \
+ if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) { \
+ set_page_func(page); \
+ return; \
+ } \
+ btrfs_subpage_clamp_range(page, &start, &len); \
+ btrfs_subpage_set_##name(fs_info, page, start, len); \
+} \
+void btrfs_page_clamp_clear_##name(const struct btrfs_fs_info *fs_info, \
+ struct page *page, u64 start, u32 len) \
+{ \
+ if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) { \
+ clear_page_func(page); \
+ return; \
+ } \
+ btrfs_subpage_clamp_range(page, &start, &len); \
+ btrfs_subpage_clear_##name(fs_info, page, start, len); \
+} \
+bool btrfs_page_clamp_test_##name(const struct btrfs_fs_info *fs_info, \
+ struct page *page, u64 start, u32 len) \
+{ \
+ if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) \
+ return test_page_func(page); \
+ btrfs_subpage_clamp_range(page, &start, &len); \
+ return btrfs_subpage_test_##name(fs_info, page, start, len); \
}
IMPLEMENT_BTRFS_PAGE_OPS(uptodate, SetPageUptodate, ClearPageUptodate,
PageUptodate);