Merge pull request #2296 from reaperhulk/argon2-threads

cfg_if::cfg_if! {

    if #[cfg(all(ossl320, not(osslconf = "OPENSSL_NO_ARGON2")))] {

        use std::cmp;

        use std::ffi::{c_char, c_void};

        use std::mem::MaybeUninit;

        use std::ptr;

        /// Derives a key using the argon2id algorithm.

        ///

        /// This function currently does not support multi-threaded operation, so

        /// lanes greater than 1 will be processed sequentially.

        /// To use multiple cores to process the lanes in parallel you must

        /// set a global max thread count using `OSSL_set_max_threads`. On

        /// builds with no threads all lanes will be processed sequentially.

        ///

        /// Requires OpenSSL 3.2.0 or newer.

        #[allow(clippy::too_many_arguments)]

                ffi::init();

                let libctx = ctx.map_or(ptr::null_mut(), ForeignTypeRef::as_ptr);

                let max_threads = ffi::OSSL_get_max_threads(libctx);

                let mut threads = 1;

                // If max_threads is 0, then this isn't a threaded build.

                // If max_threads is > u32::MAX we need to clamp since

                // argon2id's threads parameter is a u32.

                if max_threads > 0 {

                    threads = cmp::min(lanes, cmp::min(max_threads, u32::MAX as u64) as u32);

                }

                let mut params: [ffi::OSSL_PARAM; 10] =

                    core::array::from_fn(|_| MaybeUninit::<ffi::OSSL_PARAM>::zeroed().assume_init());

                let mut idx = 0;