snd_pcm_stream_lock(9)

💅 NAME 💅

Okay so this is snd_pcm_stream_lock from the Kernel API Manual, and its whole job is literally: Lock the PCM stream 🔒✨

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🌟 SYNOPSIS 🌟

void snd_pcm_stream_lock (struct snd_pcm_substream *substream );

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🎀 ARGUMENTS 🎀

• substream — the PCM substream, bestie. That's the one thing you pass in. 🫶

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🌸 DESCRIPTION 🌸

So the way this works: it locks the PCM stream's spinlock or mutex, depending on the nonatomic flag of the given substream. Like, it checks that flag and picks the lock vibe accordingly. 🔐

It also takes the global link rw lock (or rw sem), too, for avoiding the race with linked streams. No cap, it's doing that extra locking so linked-stream chaos doesn't sneak in. 💅

It's giving “do the lock, move on” energy — the synopsis says void, so there's no return value to catch. Periodt. 🎀

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🦋 SEE ALSO 🦋

Kernel file ./sound/core/pcm_native.c says go check these besties:

• snd_pcm_stream_unlock(9)
• snd_pcm_stream_lock_irq(9)
• snd_pcm_stream_unlock_irq(9)
• snd_pcm_stream_unlock_irqrestore(9)
• snd_pcm_set_state(9)
• snd_pcm_get_state(9)
• snd_pcm_hw_params_choose(9)
• snd_pcm_start(9)
• snd_pcm_stop(9)
• snd_pcm_drain_done(9)
• snd_pcm_stop_xrun(9)
• snd_pcm_suspend_all(9)
• snd_pcm_prepare(9)
• snd_pcm_kernel_ioctl(9)
• snd_pcm_lib_default_mmap(9)
• snd_pcm_lib_mmap_iomem(9)

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source/version: ./sound/core · date: October 2026 · page: snd_pcm_stream_lock(9) — mwah, bye bestie 💖🎀