vhost_discard_vq_desc(9)

💅 vhost_discard_vq_desc — the kernel API manual, bestie edition 🎀

okay so picture this: it's vhost_discard_vq_desc(9), from the Kernel API Manual, and she's literally the undo button for your virtqueue. yes ma'am, we're doing kernel plumbing today and it's gonna slay 🦋

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✨ NAME ✨

vhost_discard_vq_desc — reverse the effect of vhost_get_vq_desc_n() 🙈

like, un-do it. rewind. take it back. we're not doing that anymore 💅

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🌸 SYNOPSIS 🌸

void vhost_discard_vq_desc (struct vhost_virtqueue *vq , int nbufs ,
       unsigned int ndesc );

that's the whole vibe. no return value, she just goes in and fixes things behind the scenes ✨

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🎀 ARGUMENTS 🎀

• vq — the target virtqueue 👑 this is the main character, the queue we're rolling back
• nbufs — number of buffers to roll back 🍓 like, how many of them we're un-consuming
• ndesc — number of descriptors to roll back 🧚 the descriptor count getting the rewind treatment

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💖 DESCRIPTION 💖

so here's the tea: sometimes you try to use some buffers that vhost_get_vq_desc_n handed you, and it just… doesn't work out 😭 failed attempt, no cap.

vhost_discard_vq_desc rewinds the internal consumer cursors after that failed attempt. it's giving "ctrl+Z but for kernel bookkeeping" — the buffers go back to where they were, the cursors scooch backwards, and everything is aligned again. icon behavior, honestly 🫶

no judgement, we've all had a failed attempt. she's not mad, she's just resetting the cursors 🔥

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/vhost/vhost.c 📁
• __vhost_worker_flush(9)
• vhost_get_vq_desc_n(9) — the one she's reversing, iykyk 💜

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and that's the whole page bestie, no notes 💅

signing off from ./drivers/vhost — October 2026, vhost_discard_vq_desc(9), living her best life in the Kernel API Manual ⭐🧚‍♀️