man: update struct io_uring_buf_reg documentation

Was missing the flags field, and also the newly added 'min_left' field
that can be used with incrementally consumed buffers to set a minimum
number of bytes that should be left in a buffer for it to still be
considered valid. If less than 'min_left' is left it'll be marked as
done (IORING_CQE_F_BUF_MORE not set), and the next consumption point
will be the next buffer in that group.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

man/io_uring_register.2

diff --git a/man/io_uring_register.2 b/man/io_uring_register.2
index e00b82b..1b36ce1 100644
--- a/man/io_uring_register.2
+++ b/man/io_uring_register.2
@@ -635,8 +635,9 @@
     __u64 ring_addr;
     __u32 ring_entries;
     __u16 bgid;
-    __u16 pad;
-    __u64 resv[3];
+    __u16 flags;
+    __u32 min_left;
+    __u32 resv[5];
 };
 .EE
 .in
@@ -662,8 +663,15 @@
 .B IORING_CQE_F_BUFFER
 set in their
 .I flags
-member, which will also contain the specific ID of the buffer selected. The rest
-of the fields are reserved and must be cleared to zero.
+member, which will also contain the specific ID of the buffer selected.
+.I min_left
+is the minimum value that should be left in an incrementally consumed buffer
+ring for the buffer to be considered valid. If not set, defaults to a single
+byte. Only valid with
+.B IOU_PBUF_RING_INC
+set in
+.I flags .
+The rest of the fields are reserved and must be cleared to zero.
 
 .I nr_args
 must be set to 1.

man/io_uring_register_buf_ring.3

diff --git a/man/io_uring_register_buf_ring.3 b/man/io_uring_register_buf_ring.3
index f7265a7..14f5cde 100644
--- a/man/io_uring_register_buf_ring.3
+++ b/man/io_uring_register_buf_ring.3
@@ -39,8 +39,9 @@
     __u64 ring_addr;
     __u32 ring_entries;
     __u16 bgid;
-    __u16 pad;
-    __u64 resv[3];
+    __u16 flags;
+    __u32 min_left;
+    __u32 resv[5];
 };
 .EE
 .in
@@ -65,8 +66,15 @@
 .B IORING_CQE_F_BUFFER
 set in their
 .I flags
-member, which will also contain the specific ID of the buffer selected. The rest
-of the fields are reserved and must be cleared to zero.
+member, which will also contain the specific ID of the buffer selected.
+.I min_left
+is the minimum value that should be left in an incrementally consumed buffer
+ring for the buffer to be considered valid. If not set, defaults to a single
+byte. Only valid with
+.B IOU_PBUF_RING_INC
+set in
+.I flags .
+The rest of the fields are reserved and must be cleared to zero.
 
 The
 .I flags