virtqueue_ad...uf_premapped(9)

💅 virtqueue_ad...uf_premapped(9) — from the Kernel API Manual, bestie ✨

okay so picture this: you're deep in kernel land, you've got a struct virtqueue, and you want the other side to be able to see some output buffers. That's it. That's the whole gig. Welcome to virtqueue_add_outbuf_premapped, my love 🫶

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🌸 NAME 🌸

virtqueue_add_outbuf_premapped — expose output buffers to other end

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✨ SYNOPSIS ✨

int virtqueue_add_outbuf_premapped (struct virtqueue *vq , struct scatterlist *sg , unsigned int num , void *data , gfp_t gfp );

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🎀 ARGUMENTS 🎀

• vq — the struct virtqueue we're talking about. the main character, basically 👑
• sg — the scatterlist. and bestie, it must be well-formed and terminated! no cap, this is not optional 💀
• num — the number of entries in sg that are readable by the other side.
• data — the token identifying the buffer. your little name tag for it 🏷️
• gfp — how to do memory allocations (if necessary). iykyk 🌈

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💖 DESCRIPTION 💖

Caller must ensure we don't call this with other virtqueue operations at the same time (except where noted).

fr fr, read that again. it's giving "one at a time, queen." no overlapping virtqueue ops unless the docs explicitly say otherwise 🙈

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🔥 RETURN 🔥

Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).

so: 0 = slayed ✨, negative = it's giving struggle 😭

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🦋 SEE ALSO 🦋

Kernel file ./drivers/virtio/virtio_ring.c, plus the whole friend group:

• virtqueue_add_sgs(9)
• virtqueue_add_outbuf(9)
• virtqueue_add_inbuf(9)
• virtqueue_add_inbuf_cache_clean(9)
• virtqueue_add_inbuf_ctx(9)
• virtqueue_add_inbuf_premapped(9)
• virtqueue_dma_dev(9)
• virtqueue_kick_prepare(9)
• virtqueue_notify(9)
• virtqueue_kick(9)
• virtqueue_get_buf_ctx(9)
• virtqueue_disable_cb(9)
• virtqueue_enable_cb_prepare(9)
• virtqueue_poll(9)
• virtqueue_enable_cb(9)
• virtqueue_enable_cb_delayed(9)
• virtqueue_detach_unused_buf(9)
• vring_interrupt(9)
• virtqueue_resize(9)
• virtqueue_reset(9)
• virtqueue_get_vring_size(9)
• virtqueue_map_alloc_coherent(9)
• virtqueue_map_free_coherent(9)
• virtqueue_map_page_attrs(9)
• virtqueue_unmap_page_attrs(9)
• virtqueue_map_single_attrs(9)
• virtqueue_unmap_single_attrs(9)
• virtqueue_map_mapping_error(9)
• virtqueue_map_need_sync(9)
• virtqueue_map_sync_single_range_for_cpu(9)
• virtqueue_map_sync_single_range_for_device(9)

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and that's the whole page, bestie 🌈💜 live from ./drivers/virtio, dated October 2026, courtesy of the Kernel API Manual — go forth and map those buffers responsibly 🧚‍♀️⭐