[PATCH] blktrace: allow for unaligned events

Unfortunately it looks like we have to support this for now,
as it appears relayfs will still miss events on buffer wraps
for the read cases.

diff --git a/blktrace.c b/blktrace.c
index 559cb7f248ba5a5979743a2eb2ecf6d1c503d8a6..852c9252d53ac2e406f90d24365b5bd648f604a6 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -292,6 +292,22 @@ static void *extract_data(struct thread_information *tip, int nb)
        return NULL;
 }
 
+static int get_event(struct thread_information *tip, struct blk_io_trace *bit)
+{
+       void *p = &bit->sequence;
+
+       do {
+               if (read_data(tip, bit, sizeof(bit->magic)))
+                       return -1;
+
+       } while (!CHECK_MAGIC(bit));
+
+       if (!read_data(tip, p, sizeof(*bit) - sizeof(bit->magic)))
+               return 0;
+
+       return -1;
+}
+
 static inline void tip_fd_unlock(struct thread_information *tip)
 {
        if (tip->fd_lock)
@@ -333,7 +349,7 @@ static void *extract(void *arg)
 
        pdu_data = NULL;
        while (!is_done()) {
-               if (read_data(tip, &t, sizeof(t)))
+               if (get_event(tip, &t))
                        break;
 
                if (verify_trace(&t))