virtsnd_pcm_msg_send(9)

💌 NAME

virtsnd_pcm_msg_send — bestie, this is the one that sends your asynchronous I/O messages ✨

So this page lives in the Kernel API Manual, section 9, and it's literally all about yeeting async I/O messages into the virtqueue 🎀

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🌸 SYNOPSIS

int virtsnd_pcm_msg_send (struct virtio_pcm_substream *vss , unsigned
long offset , unsigned long bytes );

That's the whole signature, no cap 🫶

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💅 ARGUMENTS

• vss — the VirtIO PCM substream 🎵 like, the whole reason we're here.
• offset — the starting position that has been updated 👀
• bytes — how many bytes got updated, fr fr.

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🔥 DESCRIPTION

okay so here's the vibe ✨ all the messages are organized in an ordered circular list — that part matters, don't forget it 🌀

Every single time you call this function, all the currently non-enqueued messages get added to the virtqueue 💫 and to figure out which messages actually need to be added, the function uses offset and bytes. That's the whole trick, iykyk 🤫

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🫶 CONTEXT

Any context 💖 but listen: it expects the tx/rx queue and the VirtIO substream spinlocks to be held by the caller — so like, hold those locks before you call it, bestie, or it's giving chaos 😭🔒

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⭐ RETURN

0 on success, -errno on failure 🎀 iconic behavior honestly.

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👑 SEE ALSO

• Kernel file ./sound/virtio/virtio_pcm_msg.c
• struct virtio_pcm_msg(9)
• enum pcm_msg_sg_index(9)
• virtsnd_pcm_sg_num(9)
• virtsnd_pcm_sg_from(9)
• virtsnd_pcm_msg_alloc(9)
• virtsnd_pcm_msg_free(9)
• virtsnd_pcm_msg_pending_num(9)
• virtsnd_pcm_msg_complete(9)
• virtsnd_pcm_notify_cb(9)
• virtsnd_pcm_tx_notify_cb(9)
• virtsnd_pcm_rx_notify_cb(9)
• virtsnd_pcm_ctl_msg_alloc(9)

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and that's the page!! 💜 this little gem ships out of ./sound/virtio, dated October 2026, and it's filed under virtsnd_pcm_msg_send(9) — go forth and enqueue your messages, main character 🌈🦋🍓