[xen stable-4.17] tools/ocaml/xb: Drop Xs_ring.write

[patchbot@xxxxxxx]

commit f0e653fb4aea77210b8096c170e82de3c2039d89
Author:     Edwin Török <edvin.torok@xxxxxxxxxx>
AuthorDate: Fri Dec 16 18:25:20 2022 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Feb 9 15:55:25 2023 +0000

    tools/ocaml/xb: Drop Xs_ring.write
    
    This function is unusued (only Xs_ring.write_substring is used), and the
    bytes/string conversion here is backwards: the C stub implements the bytes
    version and then we use a Bytes.unsafe_of_string to convert a string into
    bytes.
    
    However the operation here really is read-only: we read from the string and
    write it to the ring, so the C stub should implement the read-only string
    version, and if needed we could use Bytes.unsafe_to_string to be able to 
send
    'bytes'. However that is not necessary as the 'bytes' version is dropped 
above.
    
    Signed-off-by: Edwin Török <edvin.torok@xxxxxxxxxx>
    Acked-by: Christian Lindig <christian.lindig@xxxxxxxxxx>
    (cherry picked from commit 01f139215e678c2dc7d4bb3f9f2777069bb1b091)
---
 tools/ocaml/libs/xb/xs_ring.ml      | 5 +----
 tools/ocaml/libs/xb/xs_ring_stubs.c | 2 +-
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/tools/ocaml/libs/xb/xs_ring.ml b/tools/ocaml/libs/xb/xs_ring.ml
index db7f86bd27..dd5e014a33 100644
--- a/tools/ocaml/libs/xb/xs_ring.ml
+++ b/tools/ocaml/libs/xb/xs_ring.ml
@@ -25,14 +25,11 @@ module Server_features = Set.Make(struct
 end)
 
 external read: Xenmmap.mmap_interface -> bytes -> int -> int = 
"ml_interface_read"
-external write: Xenmmap.mmap_interface -> bytes -> int -> int = 
"ml_interface_write"
+external write_substring: Xenmmap.mmap_interface -> string -> int -> int = 
"ml_interface_write"
 
 external _internal_set_server_features: Xenmmap.mmap_interface -> int -> unit 
= "ml_interface_set_server_features" [@@noalloc]
 external _internal_get_server_features: Xenmmap.mmap_interface -> int = 
"ml_interface_get_server_features" [@@noalloc]
 
-let write_substring mmap buff len =
-       write mmap (Bytes.unsafe_of_string buff) len
-
 let get_server_features mmap =
        (* NB only one feature currently defined above *)
        let x = _internal_get_server_features mmap in
diff --git a/tools/ocaml/libs/xb/xs_ring_stubs.c 
b/tools/ocaml/libs/xb/xs_ring_stubs.c
index 1f58524535..1243c63f03 100644
--- a/tools/ocaml/libs/xb/xs_ring_stubs.c
+++ b/tools/ocaml/libs/xb/xs_ring_stubs.c
@@ -112,7 +112,7 @@ CAMLprim value ml_interface_write(value ml_interface,
        CAMLlocal1(ml_result);
 
        struct mmap_interface *interface = GET_C_STRUCT(ml_interface);
-       const unsigned char *buffer = Bytes_val(ml_buffer);
+       const char *buffer = String_val(ml_buffer);
        int len = Int_val(ml_len);
        int result;
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.17