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-rw-r--r--lib/errseq.c23
1 files changed, 9 insertions, 14 deletions
diff --git a/lib/errseq.c b/lib/errseq.c
index df782418b333..81f9e33aa7e7 100644
--- a/lib/errseq.c
+++ b/lib/errseq.c
@@ -111,27 +111,22 @@ EXPORT_SYMBOL(errseq_set);
111 * errseq_sample() - Grab current errseq_t value. 111 * errseq_sample() - Grab current errseq_t value.
112 * @eseq: Pointer to errseq_t to be sampled. 112 * @eseq: Pointer to errseq_t to be sampled.
113 * 113 *
114 * This function allows callers to sample an errseq_t value, marking it as 114 * This function allows callers to initialise their errseq_t variable.
115 * "seen" if required. 115 * If the error has been "seen", new callers will not see an old error.
116 * If there is an unseen error in @eseq, the caller of this function will
117 * see it the next time it checks for an error.
116 * 118 *
119 * Context: Any context.
117 * Return: The current errseq value. 120 * Return: The current errseq value.
118 */ 121 */
119errseq_t errseq_sample(errseq_t *eseq) 122errseq_t errseq_sample(errseq_t *eseq)
120{ 123{
121 errseq_t old = READ_ONCE(*eseq); 124 errseq_t old = READ_ONCE(*eseq);
122 errseq_t new = old;
123 125
124 /* 126 /* If nobody has seen this error yet, then we can be the first. */
125 * For the common case of no errors ever having been set, we can skip 127 if (!(old & ERRSEQ_SEEN))
126 * marking the SEEN bit. Once an error has been set, the value will 128 old = 0;
127 * never go back to zero. 129 return old;
128 */
129 if (old != 0) {
130 new |= ERRSEQ_SEEN;
131 if (old != new)
132 cmpxchg(eseq, old, new);
133 }
134 return new;
135} 130}
136EXPORT_SYMBOL(errseq_sample); 131EXPORT_SYMBOL(errseq_sample);
137 132