blk_crypto_u...capabilities(9)

📦 version 7.3.1, in nixpkgs unstable

💖 blk_crypto_update_capabilities 💖

okay so bestie, welcome to this little entry from the Kernel API Manual. The main character is blk_crypto_update_capabilities, and she is literally here to update one crypto profile's capabilities so they match another crypto profile's capabilities. no cap, that's the assignment. 💅

🌸 NAME 🌸

blk_crypto_update_capabilities — update the capabilities of a crypto profile to match those of another crypto profile. slay. ✨

✨ SYNOPSIS ✨

void blk_crypto_update_capabilities (struct blk_crypto_profile *dst ,
const struct blk_crypto_profile *src );

Return type is void, so there's no return value coming back — she does the update and exits, periodt. 💁‍♀️

🎀 ARGUMENTS 🎀

  • dst — the crypto profile whose capabilities to update. she's the one getting the glow-up, iykyk.
  • src — the crypto profile whose capabilities this function will update dst's capabilities to. she's the inspo, fr fr.

🦋 DESCRIPTION 🦋

Blk-crypto has a rule and it is not optional: the crypto capabilities that were advertised when a bio was created have to keep being supported by the device until that bio is ended. literally until the bio is over, bestie. This in turn means a device cannot shrink its advertised crypto capabilities without any explicit synchronization with upper layers. no sneaky downgrade. 🚫

So if there's no such explicit synchronization, src must support all the crypto capabilities that dst does — i.e. we need blk_crypto_has_capabilities(src, dst). that's the vibe check. ✅

Also note: as long as the crypto capabilities are being expanded, the order of updates becoming visible is not important. why? because it's alright for blk-crypto to see stale values — they only cause blk-crypto to believe that a crypto capability isn't supported when it actually is — which might result in blk-crypto-fallback being used if available, or the bio being failed. not ideal, but that's the consequence, periodt. 💀

👑 SEE ALSO 👑

Kernel file ./block/blk-crypto-profile.c, plus the whole reference friend group:

signed off from the ./block corner of the Kernel API Manual, dated October 2026, under the page label blk_crypto_u...capabilities(9). bye bestie 🫶💖

📦 where this page comes from