Merge tag 'drm-intel-next-fixes-2018-06-08-2' of git://anongit.freedesktop.org/drm...

[linux.git] / lib / errseq.c

diff --git a/lib/errseq.c b/lib/errseq.c
index df782418b333eedea39cdb793c38ad623f96a707..81f9e33aa7e72aa7f3a524ff061aa3c9d48fe1a9 100644 (file)
--- a/lib/errseq.c
+++ b/lib/errseq.c
@@ -111,27 +111,22 @@ EXPORT_SYMBOL(errseq_set);
  * errseq_sample() - Grab current errseq_t value.
  * @eseq: Pointer to errseq_t to be sampled.
  *
- * This function allows callers to sample an errseq_t value, marking it as
- * "seen" if required.
+ * This function allows callers to initialise their errseq_t variable.
+ * If the error has been "seen", new callers will not see an old error.
+ * If there is an unseen error in @eseq, the caller of this function will
+ * see it the next time it checks for an error.
  *
+ * Context: Any context.
  * Return: The current errseq value.
  */
 errseq_t errseq_sample(errseq_t *eseq)
 {
        errseq_t old = READ_ONCE(*eseq);
-       errseq_t new = old;
 
-       /*
-        * For the common case of no errors ever having been set, we can skip
-        * marking the SEEN bit. Once an error has been set, the value will
-        * never go back to zero.
-        */
-       if (old != 0) {
-               new |= ERRSEQ_SEEN;
-               if (old != new)
-                       cmpxchg(eseq, old, new);
-       }
-       return new;
+       /* If nobody has seen this error yet, then we can be the first. */
+       if (!(old & ERRSEQ_SEEN))
+               old = 0;
+       return old;
 }
 EXPORT_SYMBOL(errseq_sample);