[Xen-changelog] [xen master] tools/libxc: unused attribute in DECLARE_HYPERCALL_BUFFER_SHADOW

[patchbot@xxxxxxx]

commit 22c06289dccb2c45ed47ee39d285e7ee24174f1a
Author:     Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
AuthorDate: Thu May 14 16:55:07 2015 +0800
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Thu May 14 13:01:54 2015 +0100

    tools/libxc: unused attribute in DECLARE_HYPERCALL_BUFFER_SHADOW
    
    There are cases where we only need to use the hypercall buffer data,
    and do not use the xc_hypercall_buffer_t struct.
    DECLARE_HYPERCALL_BUFFER_SHADOW defines a user pointer that can allow
    us to access the hypercall buffer data but it also defines a
    xc_hypercall_buffer_t that we don't use, the compiler will report arg
    unused error.
    Add __attribute__((unused)) before xc_hypercall_buffer_t to avoid
    the compiler error.
    
    Example cases:
    In send_all_pages(), we only need to use the hypercall buffer data
    which is a dirty bitmap, we set the dirty bitmap to all dirty and call
    send_dirty_pages, we will not use the xc_hypercall_buffer_t and hypercall
    to retrieve the dirty bitmap.
    In send_some_pages(), we will also only need to use the dirty_bitmap.
    the retrieve dirty bitmap hypercall are done by the caller.
    
    Signed-off-by: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
    CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
    CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
    CC: Wei Liu <wei.liu2@xxxxxxxxxx>
    CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
---
 tools/libxc/include/xenctrl.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 09faa7f..5a9f76a 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -289,6 +289,7 @@ typedef struct xc_hypercall_buffer xc_hypercall_buffer_t;
  */
 #define DECLARE_HYPERCALL_BUFFER_SHADOW(_type, _name, _hbuf)   \
     _type *(_name) = (_hbuf)->hbuf;                            \
+    __attribute__((unused))                                    \
     xc_hypercall_buffer_t XC__HYPERCALL_BUFFER_NAME(_name) = { \
         .hbuf = (void *)-1,                                    \
         .param_shadow = (_hbuf),                               \
--
generated by git-patchbot for /home/xen/git/xen.git#master

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