From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Qu Wenruo <wqu@suse.com>, Chris Mason <clm@fb.com>,
Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert@linux-m68k.org>,
noreply@ellerman.id.au
Subject: [PATCH -next] btrfs: lzo: Mask instead of divide to fix 32-bit build
Date: Tue, 5 Oct 2021 11:34:06 +0200 [thread overview]
Message-ID: <20211005093406.1241222-1-geert@linux-m68k.org> (raw)
On 32-bit builds (e.g. m68k):
ERROR: modpost: "__umoddi3" [fs/btrfs/btrfs.ko] undefined!
"cur_in - start" is 64-bit, while sectorsize is u32.
As sectorsize is always a power of two, the 64-by-32 modulo operation
can be replaced by a much cheaper bitwise AND with "sectorsize - 1".
Fixes: 0078783c7089fc83 ("btrfs: rework lzo_compress_pages() to make it subpage compatible")
Reported-by: noreply@ellerman.id.au
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
Compile-tested only.
---
fs/btrfs/lzo.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 47003cec4046f13e..d08f9eba49dab3cd 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -211,7 +211,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
*/
cur_out += LZO_LEN;
while (cur_in < start + len) {
- u32 sector_off = (cur_in - start) % sectorsize;
+ u32 sector_off = (cur_in - start) & (sectorsize - 1);
u32 in_len;
size_t out_len;
--
2.25.1
next reply other threads:[~2021-10-05 9:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 9:34 Geert Uytterhoeven [this message]
2021-10-05 9:41 ` [PATCH -next] btrfs: lzo: Mask instead of divide to fix 32-bit build Qu Wenruo
2021-10-05 23:23 ` David Sterba
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