Re: [PATCH] io_uring/kbuf: Fix size for shared buffer ring

[Jens Axboe <axboe@kernel.dk>]

On 4/27/23 8:31?AM, Tudor Cretu wrote:
> The size of the ring is the product of ring_entries and the size of
> struct io_uring_buf. Using struct_size is equivalent to
>   (ring_entries + 1) * sizeof(struct io_uring_buf)
> and generates an off-by-one error. Fix it by using size_mul directly.

Looks right, so we're doing one entry too much. This is probably a
remnant of when the initial version had it done a bit differently, but
we overlaid the tail with the first entry reserved field.

-- 
Jens Axboe