cutils: Export only buffer_is_zero

Since the two users don't make use of the returned offset,
beyond ensuring that the entire buffer is zero, consider the
can_use_buffer_find_nonzero_offset and buffer_find_nonzero_offset
functions internal.
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>
Message-Id: <1472496380-19706-4-git-send-email-rth@twiddle.net>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

include/qemu/cutils.h

@@ -168,8 +168,6 @@ int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
 /* used to print char* safely */
 #define STR_OR_NULL(str) ((str) ? (str) : "null")
 
-bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len);
-size_t buffer_find_nonzero_offset(const void *buf, size_t len);
 bool buffer_is_zero(const void *buf, size_t len);
 
 /*

migration/ram.c

@@ -73,7 +73,7 @@ static const uint8_t ZERO_TARGET_PAGE[TARGET_PAGE_SIZE];
 
 static inline bool is_zero_range(uint8_t *p, uint64_t size)
 {
-    return buffer_find_nonzero_offset(p, size) == size;
+    return buffer_is_zero(p, size);
 }
 
 /* struct contains XBZRLE cache and a static page

migration/rdma.c

@@ -1934,10 +1934,7 @@ retry:
              * memset() + madvise() the entire chunk without RDMA.
              */
 
-            if (can_use_buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr,
-                                                   length)
-                   && buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr,
-                                                    length) == length) {
+            if (buffer_is_zero((void *)(uintptr_t)sge.addr, length)) {
                 RDMACompress comp = {
                                         .offset = current_addr,
                                         .value = 0,

util/bufferiszero.c

@@ -192,9 +192,9 @@ static bool avx2_support(void)
     return b & bit_AVX2;
 }
 
-bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
+static bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
          __attribute__ ((ifunc("can_use_buffer_find_nonzero_offset_ifunc")));
-size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
+static size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
          __attribute__ ((ifunc("buffer_find_nonzero_offset_ifunc")));
 
 static void *buffer_find_nonzero_offset_ifunc(void)
@@ -215,12 +215,12 @@ static void *can_use_buffer_find_nonzero_offset_ifunc(void)
 }
 #pragma GCC pop_options
 #else
-bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
+static bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
 {
     return can_use_buffer_find_nonzero_offset_inner(buf, len);
 }
 
-size_t buffer_find_nonzero_offset(const void *buf, size_t len)
+static size_t buffer_find_nonzero_offset(const void *buf, size_t len)
 {
     return buffer_find_nonzero_offset_inner(buf, len);
 }