On Thu, Apr 21, 2022 at 1:37 PM Stefan Roesch <shr@xxxxxx> wrote:
>
> This adds the overflow processing for large CQE's.
>
> This adds two parameters to the io_cqring_event_overflow function and
> uses these fields to initialize the large CQE fields.
>
> Allocate enough space for large CQE's in the overflow structue. If no
> large CQE's are used, the size of the allocation is unchanged.
>
> The cqe field can have a different size depending if its a large
> CQE or not. To be able to allocate different sizes, the two fields
> in the structure are re-ordered.
>
> Co-developed-by: Jens Axboe <axboe@xxxxxxxxx>
> Signed-off-by: Stefan Roesch <shr@xxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> fs/io_uring.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index ff6229b6df16..50efced63ec9 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -220,8 +220,8 @@ struct io_mapped_ubuf {
> struct io_ring_ctx;
>
> struct io_overflow_cqe {
> - struct io_uring_cqe cqe;
> struct list_head list;
> + struct io_uring_cqe cqe;
> };
>
> struct io_fixed_file {
> @@ -2016,13 +2016,17 @@ static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
> while (!list_empty(&ctx->cq_overflow_list)) {
> struct io_uring_cqe *cqe = io_get_cqe(ctx);
> struct io_overflow_cqe *ocqe;
> + size_t cqe_size = sizeof(struct io_uring_cqe);
> +
> + if (ctx->flags & IORING_SETUP_CQE32)
> + cqe_size <<= 1;
>
> if (!cqe && !force)
> break;
> ocqe = list_first_entry(&ctx->cq_overflow_list,
> struct io_overflow_cqe, list);
> if (cqe)
> - memcpy(cqe, &ocqe->cqe, sizeof(*cqe));
> + memcpy(cqe, &ocqe->cqe, cqe_size);
> else
> io_account_cq_overflow(ctx);
>
> @@ -2111,11 +2115,15 @@ static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
> }
>
> static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
> - s32 res, u32 cflags)
> + s32 res, u32 cflags, u64 extra1, u64 extra2)
> {
> struct io_overflow_cqe *ocqe;
> + size_t ocq_size = sizeof(struct io_overflow_cqe);
>
> - ocqe = kmalloc(sizeof(*ocqe), GFP_ATOMIC | __GFP_ACCOUNT);
> + if (ctx->flags & IORING_SETUP_CQE32)
This can go inside in a bool variable, as this check is repeated in
this function.
