[PATCH v22 00/13] ALSA: virtio: validate PCM ACK and prepare completion

[Joonho Lee <mynameisjune111@gmail.com>]

This cumulative v22 update adds an optional linked-prepare completion
hook and validates playback ACK accounting before indirect transfer.

The core hook runs after all linked prepare actions and post-actions
succeed. If an action fails, callbacks cover only the attempted prefix;
the core moves opted-in members in that prefix to SETUP before calling
back. Pre-action failures and standalone RESET do not invoke the hook.
Drivers that leave it unset retain existing prepare-failure behavior.

Virtio uses the hook to keep ACK admission closed through the core
pointer reset. Patch 5 also returns -EBADFD for an ACK on an already
XRUN member, avoiding a second linked-group XRUN request.

Playback ACK validates normalized boundary deltas, frame-to-byte
geometry, ring indices, signed ready counters, and total queued bytes
before the indirect transfer helper mutates its cursor. An invalid
paused ACK returns -EBADFD without starting a linked XRUN.

Validation: The exact-source ARM64 W=1/KASAN/LOCKDEP build passed;
final-r4 snd-pcm and virtio_snd modules match the previous build, and
Image executable sections and System.map match. The W=1 stage 04–13
build chain passed without warnings or errors. The v22-only checkpatch
delta reported zero errors, warnings, or checks. The bounded playback
ACK helper passed 23 candidate-only cases. The prepare-completion QEMU
probe passed six lifecycle cases, including a later member's OPEN
pre-action abort. Normal playback passed in QEMU with RW and MMAP,
including prepare, fill, START, supported pause/resume, drain, drop, and
reopen. Four ordinary/staged capture paths (RW/MMAP) passed with 14
oracle captures, including post-reset capture checks.

The prepare-ordering diagnosis comes from static source inspection; no
baseline runtime test was run. KCSAN and physical-device testing remain
pending.