common/compat: resolve signedness warnings

    /home/ubuntu/ceph/src/common/compat.cc:365:11: warning: comparison of integers of different signs: 'int' and 'const size_t' (aka 'const unsigned long long') [-Wsign-compare]
        if (r < iov[i].iov_len)
            ~ ^ ~~~~~~~~~~~~~~
    /home/ubuntu/ceph/src/common/compat.cc:380:11: warning: comparison of integers of different signs: 'int' and 'const size_t' (aka 'const unsigned long long') [-Wsign-compare]
        if (r < iov[i].iov_len)
            ~ ^ ~~~~~~~~~~~~~~
    6 warnings generated.

Signed-off-by: Patrick Donnelly <[email protected]>

Author: batrick

src/common/compat.cc

@@ -368,7 +368,7 @@ ssize_t preadv(int fd, const struct iovec *iov, int iov_cnt) {
     if (r < 0)
       return r;
     read += r;
-    if (r < iov[i].iov_len)
+    if ((unsigned)r < iov[i].iov_len)
       break;
   }
 
@@ -383,7 +383,7 @@ ssize_t writev(int fd, const struct iovec *iov, int iov_cnt) {
     if (r < 0)
       return r;
     written += r;
-    if (r < iov[i].iov_len)
+    if ((unsigned)r < iov[i].iov_len)
       break;
   }