mpi3mr_map_data_buffer_dma(9)

📦 version 7.3.1, in nixpkgs unstable

💅 mpi3mr_map_data_buffer_dma(9) — like, the Kernel API Manual era 🎀

okay bestie, buckle up, because this one is actually kind of the moment. we're in the Kernel API Manual, function mpi3mr_map_data_buffer_dma. yes the name is a mouthful, no you're not allowed to abbreviate it, it's giving "my parents named me after the whole alphabet" energy but we love her 💖

✨ NAME ✨

mpi3mr_map_data_buffer_dma — build dma descriptors for data buffers. that's it, that's the whole job, she builds dma descriptors for data buffers and she does it well 🦋

🌸 SYNOPSIS 🌸

int mpi3mr_map_data_buffer_dma (struct mpi3mr_ioc *mrioc , struct
mpi3mr_buf_map *drv_buf , u16 desc_count );

look at her go. three args, returns an int, absolute main character energy 👑

🎀 ARGUMENTS 🎀

  • mrioc — the adapter instance reference. yep, your whole adapter, just vibing there as a pointer 💅
  • drv_buf — the buffer map descriptor. this is the little map that says where stuff goes 🗺️
  • desc_count — the number of dma descriptors that have already been consumed. key word: already. she's counting what's gone, not what's left 🙈

💖 DESCRIPTION 💖

okay so here's the tea ☕ — this function does two things and she's highkey good at both:

  1. she computes how many pre-allocated DMA descriptors are required for the given data buffer 🔥
  2. and if that number of descriptors is free, she sets up the mapping of the scattered DMA address to the given data buffer ✨

and then, plot twist: if the data direction of the buffer is DMA_TO_DEVICE, the actual data gets copied over to the DMA buffers. not me being obsessed with a conditional 💀 so basically: work out how many descriptors you need, check they're actually available, map the scattered DMA address onto the buffer, and copy the real data across when the direction is DMA_TO_DEVICE. literal icon behaviour 🧚

⭐ RETURN ⭐

  • 0 on success 🎉 (slay)
  • -1 on failure 😭 (not slay)

🦋 SEE ALSO 🦋

bestie there are so many of these, and every single one ate, so we're listing them all. no skips, no cuts, we respect the whole family reunion 👑

fr fr, that's the whole page. every flag, every function, every (9) — all present and accounted for 🫶

and that's a wrap bestie!! 🌈 this gem lives over in ./drivers/scsi/mpi3mr, dated October 2026, and honestly? iconic of her. go map those buffers, ily, bye 💜🎀✨

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