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-rw-r--r--lib/librte_eal/linuxapp/kni/kni_fifo.h24
1 files changed, 18 insertions, 6 deletions
diff --git a/lib/librte_eal/linuxapp/kni/kni_fifo.h b/lib/librte_eal/linuxapp/kni/kni_fifo.h
index 025ec1c9..208d34bf 100644
--- a/lib/librte_eal/linuxapp/kni/kni_fifo.h
+++ b/lib/librte_eal/linuxapp/kni/kni_fifo.h
@@ -27,6 +27,14 @@
#include <exec-env/rte_kni_common.h>
+/* Skip some memory barriers on Linux < 3.14 */
+#ifndef smp_load_acquire
+#define smp_load_acquire(a) (*(a))
+#endif
+#ifndef smp_store_release
+#define smp_store_release(a, b) *(a) = (b)
+#endif
+
/**
* Adds num elements into the fifo. Return the number actually written
*/
@@ -35,7 +43,7 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, uint32_t num)
{
uint32_t i = 0;
uint32_t fifo_write = fifo->write;
- uint32_t fifo_read = fifo->read;
+ uint32_t fifo_read = smp_load_acquire(&fifo->read);
uint32_t new_write = fifo_write;
for (i = 0; i < num; i++) {
@@ -46,7 +54,7 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, uint32_t num)
fifo->buffer[fifo_write] = data[i];
fifo_write = new_write;
}
- fifo->write = fifo_write;
+ smp_store_release(&fifo->write, fifo_write);
return i;
}
@@ -59,7 +67,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, uint32_t num)
{
uint32_t i = 0;
uint32_t new_read = fifo->read;
- uint32_t fifo_write = fifo->write;
+ uint32_t fifo_write = smp_load_acquire(&fifo->write);
for (i = 0; i < num; i++) {
if (new_read == fifo_write)
@@ -68,7 +76,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, uint32_t num)
data[i] = fifo->buffer[new_read];
new_read = (new_read + 1) & (fifo->len - 1);
}
- fifo->read = new_read;
+ smp_store_release(&fifo->read, new_read);
return i;
}
@@ -79,7 +87,9 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, uint32_t num)
static inline uint32_t
kni_fifo_count(struct rte_kni_fifo *fifo)
{
- return (fifo->len + fifo->write - fifo->read) & (fifo->len - 1);
+ uint32_t fifo_write = smp_load_acquire(&fifo->write);
+ uint32_t fifo_read = smp_load_acquire(&fifo->read);
+ return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1);
}
/**
@@ -88,7 +98,9 @@ kni_fifo_count(struct rte_kni_fifo *fifo)
static inline uint32_t
kni_fifo_free_count(struct rte_kni_fifo *fifo)
{
- return (fifo->read - fifo->write - 1) & (fifo->len - 1);
+ uint32_t fifo_write = smp_load_acquire(&fifo->write);
+ uint32_t fifo_read = smp_load_acquire(&fifo->read);
+ return (fifo_read - fifo_write - 1) & (fifo->len - 1);
}
#ifdef RTE_KNI_VHOST