Re: [PATCH 05/18] Add io_uring IO interface

On 1/28/19 5:47 PM, Andy Lutomirski wrote:

On Mon, Jan 28, 2019 at 6:57 AM Christoph Hellwig [off-list ref] wrote:

quoted

[please make sure linux-api and linux-man are CCed on new syscalls
so that we get API experts to review them]

quoted

quoted

+static int io_import_iovec(struct io_ring_ctx *ctx, int rw,
+                        const struct io_uring_sqe *sqe,
+                        struct iovec **iovec, struct iov_iter *iter)
+{
+     void __user *buf = u64_to_user_ptr(sqe->addr);
+
+#ifdef CONFIG_COMPAT
+     if (ctx->compat)
+             return compat_import_iovec(rw, buf, sqe->len, UIO_FASTIOV,
+                                             iovec, iter);
+#endif

I think we can just check in_compat_syscall() here, which means we
can kill the ->compat member, and the separate compat version of the
setup syscall.

Since this whole API is new, I don't suppose you could introduce a
struct iovec64 or similar and just make the ABI be identical for
64-bit and 32-bit code?

Sure, that would be straight forward. Is there a strong reason to do
so outside of "that would be nice"? It's not like it's a huge amount
of code.

-- 
Jens Axboe

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