[Qemu-devel] [PATCH] nbd: simplify the nbd_request and nbd_reply structs

[Qemu-devel] [PATCH] nbd: simplify the nbd_request and nbd_reply structs

[Paolo Bonzini]

These structs are never used to represent the bytes that go over the
network.  The big-endian network data is built into a uint8_t array
in nbd_{receive,send}_{request,reply}.  Remove the unused magic field,
reorder the struct to avoid holes, and remove the packed attribute.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/block/nbd.h | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index b86a976..747bb0a 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -25,19 +25,20 @@
 #include "io/channel-socket.h"
 #include "crypto/tlscreds.h"
 
+/* Note: these are _NOT_ the same as the network representation of an NBD
+ * request and reply!
+ */
 struct nbd_request {
-    uint32_t magic;
-    uint32_t type;
     uint64_t handle;
     uint64_t from;
     uint32_t len;
-} QEMU_PACKED;
+    uint32_t type;
+};
 
 struct nbd_reply {
-    uint32_t magic;
-    uint32_t error;
     uint64_t handle;
-} QEMU_PACKED;
+    uint32_t error;
+};
 
 #define NBD_FLAG_HAS_FLAGS      (1 << 0)        /* Flags are there */
 #define NBD_FLAG_READ_ONLY      (1 << 1)        /* Device is read-only */
-- 
2.5.5

Re: [Qemu-devel] [PATCH] nbd: simplify the nbd_request and nbd_reply structs

[Eric Blake]

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On 06/13/2016 03:43 AM, Paolo Bonzini wrote:
> These structs are never used to represent the bytes that go over the
> network.  The big-endian network data is built into a uint8_t array
> in nbd_{receive,send}_{request,reply}.  Remove the unused magic field,
> reorder the struct to avoid holes, and remove the packed attribute.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/block/nbd.h | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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