Review update

Author: newpavlov

src/lib.rs

@@ -226,16 +226,29 @@ cfg_if! {
     } else if #[cfg(all(
         not(feature = "disable_urandom_fallback"),
         any(
-            // Rust supports Android API level 19 (KitKat) [0], while `getrandom(2)`
-            // was added only in level 23 (Marshmallow).
+            // Rust supports Android API level 19 (KitKat) [0] and the next upgrade targets
+            // level 21 (Lollipop) [1], while `getrandom(2)` was added only in
+            // level 23 (Marshmallow). Note that it applies only to the "old" `target_arch`es,
+            // RISC-V Android targets sufficiently new API level, same will apply for potential
+            // new Android `target_arch`es.
             // [0]: https://blog.rust-lang.org/2023/01/09/android-ndk-update-r25.html
-            target_os = "android",
+            // [1]: https://github.com/rust-lang/rust/pull/120593
+            all(
+                target_os = "android",
+                any(
+                    target_arch = "aarch64",
+                    target_arch = "arm",
+                    target_arch = "x86",
+                    target_arch = "x86_64",
+                ),
+            ),
+            // Only on these `target_arch`es Rust supports Linux kernel versions (3.2+)
+            // that precede the version (3.17) in which `getrandom(2)` was added:
+            // https://doc.rust-lang.org/stable/rustc/platform-support.html
             all(
                 target_os = "linux",
-                // Only on these `target_arch`es Rust supports Linux kernel versions (3.2+)
-                // that precede the version (3.17) in which `getrandom(2)` was added:
-                // https://doc.rust-lang.org/stable/rustc/platform-support.html
                 any(
+                    target_arch = "aarch64",
                     target_arch = "arm",
                     target_arch = "powerpc",
                     target_arch = "powerpc64",

src/linux_android_with_fallback.rs

@@ -20,8 +20,11 @@ fn is_getrandom_available() -> bool {
     if getrandom_syscall(&mut []) < 0 {
         match last_os_error().raw_os_error() {
             Some(libc::ENOSYS) => false, // No kernel support
+            // The fallback on EPERM is intentionally not done on Android since this workaround
+            // seems to be needed only for specific Linux-based products that aren't based
+            // on Android. See https://github.com/rust-random/getrandom/issues/229.
             #[cfg(target_os = "linux")]
-            Some(libc::EPERM) => false,  // Blocked by seccomp
+            Some(libc::EPERM) => false, // Blocked by seccomp
             _ => true,
         }
     } else {