rust: use libc::Ioctl type for ioctl() request argument

The second argument to ioctl() can be defined as a different type by
different libc implementations, and can be a different size on different
architectures depending on what type it is defined as. For example,
glibc defines it as `unsigned long` which may have a different size on
32-bit vs. 64-bit architectures, and musl libc defines it as `int`.

The Rust libc crate exposes a type `libc::Ioctl` which is defined as the
appropriate integer type for the given libc implementation. Using this
type for the request argument to `libc::ioctl()` ensures code will
compile correctly regardless of architecture and libc implementation.

Also, because ioctl request numbers are defined to be 32 bits
(regardless of the fact that `unsigned long` might sometimes take 64
bits on some architectures), this patch changes the Rust representation
of the bcachefs ioctl numbers to u32 instead of u64.

Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 2 insertions, 2 deletions

diff --git a/bch_bindgen/src/libbcachefs_wrapper.h b/bch_bindgen/src/libbcachefs_wrapper.h
index bc4658fb..128592c3 100644
--- a/bch_bindgen/src/libbcachefs_wrapper.h
+++ b/bch_bindgen/src/libbcachefs_wrapper.h
@@ -33,5 +33,5 @@ MARK_FIX_753(blk_mode_t, BLK_OPEN_READ);
 MARK_FIX_753(blk_mode_t, BLK_OPEN_WRITE);
 MARK_FIX_753(blk_mode_t, BLK_OPEN_EXCL);
 
-MARK_FIX_753(__u64, BCH_IOCTL_SUBVOLUME_CREATE);
-MARK_FIX_753(__u64, BCH_IOCTL_SUBVOLUME_DESTROY);
+MARK_FIX_753(__u32, BCH_IOCTL_SUBVOLUME_CREATE);
+MARK_FIX_753(__u32, BCH_IOCTL_SUBVOLUME_DESTROY);