On Wed, Sep 24, 2025 at 12:40:29PM -0700, Linus Torvalds wrote:
On Wed, 24 Sept 2025 at 12:27, Eric Biggers ebiggers@kernel.org wrote:
u32 more:1,merge:1,enc:1,write:1,init:1;
bool more;bool merge;bool enc;bool write;bool init;This actually packs horribly, since a 'bool' will take up a byte for each, so now those five bits take up 8 bytes of storage (because the five bytes will then cause the next field to have to be aligned too).
You could just keep the bitfield format, but change the 'u32' to 'bool' and get the best of both worlds, ie just do something like
u32 more:1,
bool more:1,and now you get the bit packing _and_ the automatic bool behavior.
Sure, I'll send out v2 with your suggestion.
I do think the idea of trying to re-pack the structure as part of a bug fix is a bit misguided, though. It's what caused this additional bug in the first place, and it's not like it actually matters here. (AF_ALG is rarely used, and when it is, the sockets tend not to be kept open for very long. And the entire concept of AF_ALG is a mistake anyway.)
- Eric