Messages in this thread Patch in this message | | | Date | Fri, 26 May 2023 16:35:14 +0200 | From | David Sterba <> | Subject | Re: [PATCH] btrfs: Fix csum_tree_block to avoid tripping on -Werror=array-bounds |
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On Tue, May 23, 2023 at 09:32:12PM +0200, David Sterba wrote: > On Tue, May 23, 2023 at 03:33:22PM +0800, Qu Wenruo wrote: > > On 2023/5/23 15:09, pengfuyuan wrote: > > Although even with such change, I'm still not sure if it's any better or > > worse, as most of the calculation can still be bulky. > > Yeah I think the calculations would have to be conditional or keeping > some state. I'd like to keep the structure of the first page and the > rest. > > Possible ways is to add extra condition > > for (i = 1; i < num_pages && i < INLINE_EXTENT_BUFFER_PAGES; i++)
The final version is
for (i = 1; i < num_pages && INLINE_EXTENT_BUFFER_PAGES > 1; i++)
ie. 'INLINE_EXTENT_BUFFER_PAGES > 1' can be evaluated at compile time and result in removing the for loop completely.
Pengfuyuan, can you please do a build test that it does not report the warning anymore? The diff is:
--- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -88,7 +88,6 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result) const int first_page_part = min_t(u32, PAGE_SIZE, fs_info->nodesize); SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); char *kaddr; - int i; shash->tfm = fs_info->csum_shash; crypto_shash_init(shash); @@ -96,7 +95,7 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result) crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE, first_page_part - BTRFS_CSUM_SIZE); - for (i = 1; i < num_pages; i++) { + for (int i = 1; i < num_pages && INLINE_EXTENT_BUFFER_PAGES > 1; i++) { kaddr = page_address(buf->pages[i]); crypto_shash_update(shash, kaddr, PAGE_SIZE); } --- Thanks.
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