On 6/1/24 18:01, Keith Busch wrote:
On Sat, Jun 01, 2024 at 05:36:20PM +0200, Andreas Hindborg wrote:
Keith Busch <kbusch@xxxxxxxxxx> writes:
On Sat, Jun 01, 2024 at 03:40:04PM +0200, Andreas Hindborg wrote:
+impl kernel::Module for NullBlkModule {
+ fn init(_module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust null_blk loaded\n");
+ let tagset = Arc::pin_init(TagSet::try_new(1, 256, 1), flags::GFP_KERNEL)?;
+
+ let disk = {
+ let block_size: u16 = 4096;
+ if block_size % 512 != 0 || !(512..=4096).contains(&block_size) {
+ return Err(kernel::error::code::EINVAL);
+ }
You've set block_size to the literal 4096, then validate its value
immediately after? Am I missing some way this could ever be invalid?
Good catch. It is because I have a patch in the outbound queue that allows setting
the block size via a module parameter. The module parameter patch is not
upstream yet. Once I have that up, I will send the patch with the block
size config.
Do you think it is OK to have this redundancy? It would only be for a
few cycles.
It's fine, just wondering why it's there. But it also allows values like
1536 and 3584, which are not valid block sizes, so I think you want the
check to be:
if !(512..=4096).contains(&block_size) || ((block_size & (block_size - 1)) != 0)
Can't we overload .contains() to check only power-of-2 values?
Cheers,
Hannes
