[PATCH -next] btrfs: remove set but not used variable 'num_pages'

[YueHaibing]

Fixes gcc '-Wunused-but-set-variable' warning:

fs/btrfs/ioctl.c: In function 'btrfs_extent_same':
fs/btrfs/ioctl.c:3260:6: warning:
 variable 'num_pages' set but not used [-Wunused-but-set-variable]

It not used any more since commit 9ee8234e6220 ("Btrfs: use
generic_remap_file_range_prep() for cloning and deduplication")

Signed-off-by: YueHaibing <yuehaib...@huawei.com>
---
 fs/btrfs/ioctl.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fab9443..15fc467 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3257,7 +3257,6 @@ static int btrfs_extent_same(struct inode *src, u64 loff, 
u64 olen,
                             struct inode *dst, u64 dst_loff)
 {
        int ret;
-       int num_pages = PAGE_ALIGN(BTRFS_MAX_DEDUPE_LEN) >> PAGE_SHIFT;
        u64 i, tail_len, chunk_count;
 
        /* don't make the dst file partly checksummed */
@@ -3270,8 +3269,6 @@ static int btrfs_extent_same(struct inode *src, u64 loff, 
u64 olen,
 
        tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
        chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
-       if (chunk_count == 0)
-               num_pages = PAGE_ALIGN(tail_len) >> PAGE_SHIFT;
 
        for (i = 0; i < chunk_count; i++) {
                ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,