On 12/3/24 06:56, Anuj Gupta wrote:
On Mon, Dec 02, 2024 at 09:13:14PM -0500, Martin K. Petersen wrote:
I have things running on my end on top of Jens' tree (without error
injection, that's to come).
One question, though: How am I to determine that the kernel supports
attr_ptr and IORING_RW_ATTR_FLAG_PI? Now that we no longer have separate
IORING_OP_{READ,WRITE}_META commands I can't use IO_URING_OP_SUPPORTED
to find out whether the running kernel supports PI passthrough.
Martin, right currently there is no way to probe whether the kernel
supports read/write attributes or not.
Jens, Pavel how about introducing a new IO_URING_OP_* flag (something
like IO_URING_OP_RW_ATTR_SUPPORTED) to probe whether read/write attributes
are supported or not. Something like this [*]
An IORING_FEAT_ flag might be simpler for now. Or is it in plans to
somehow support IORING_OP_READ_MULTISHOT as well?
I have to say Adding a good probing infra is long overdue. For example a
user might want to know which attributes are supported. And beyond
io_uring it might be interesting to probe whether a particular file
supports it.
[*]
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 38f0d6b10eaf..787a2df8037f 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -723,6 +723,7 @@ struct io_uring_rsrc_update2 {
#define IORING_REGISTER_FILES_SKIP (-2)
#define IO_URING_OP_SUPPORTED (1U << 0)
+#define IO_URING_OP_RW_ATTR_SUPPORTED (1U << 1)
struct io_uring_probe_op {
__u8 op;
diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index 3de75eca1c92..64e1e5d48dec 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -67,6 +67,7 @@ const struct io_issue_def io_issue_defs[] = {
io_cold_defs would be better
--
Pavel Begunkov
