blk_rq_map_kern(9)

🦋 blk_rq_map_kern(9) 🦋

okay bestie, welcome to the Kernel API Manual 💖 — this is the blk_rq_map_kern(9) page, and it's giving "map kernel data to a request, for passthrough requests." no cap, we're gonna make it make sense.

✨ NAME ✨

blk_rq_map_kern — maps kernel data onto a request, specifically for passthrough requests. iconic.

🌸 SYNOPSIS 🌸

int blk_rq_map_kern (struct request *rq , void *kbuf , unsigned int len
       , gfp_t gfp_mask );

💅 ARGUMENTS 💅

• rq — request to fill. yes, this is the request getting filled, bestie.
• kbuf — the kernel buffer. the buffer. that's it. 🫶
• len — length of user data. literally the length of user data.
• gfp_mask — memory allocation flags. the flags for allocating memory, periodt.

🧚 DESCRIPTION 🧚

the tea: data will be mapped directly if possible. otherwise a bounce buffer is used. and you can call it multiple times to append multiple buffers. so if you need to append buffers, go off. 🔥

🌈 SEE ALSO 🌈

• Kernel file ./block/blk-map.c
• bio_copy_from_iter(9)
• bio_copy_to_iter(9)
• bio_uncopy_user(9)
• bio_copy_kern(9)
• blk_rq_map_user_iov(9)
• blk_rq_unmap_user(9)

and that's the tea 🍓 — source ./block, dated October 2026, page blk_rq_map_kern(9). periodt, bestie 💜