diff mbox series

[v3,3/4] kni: fix kni kernel fifo synchronization

Message ID 1538989906-8349-3-git-send-email-phil.yang@arm.com (mailing list archive)
State Accepted, archived
Delegated to: Thomas Monjalon
Headers
Series [v3,1/4] config: use one single config option for C11 memory model |

Checks

Context Check Description
ci/checkpatch warning coding style issues
ci/Intel-compilation success Compilation OK

Commit Message

Phil Yang Oct. 8, 2018, 9:11 a.m. UTC 
  Adding memory barrier to make sure the values being synced
before updating fifo_write in kni_fifo_put and fifo_read in
kni_fifo_get.

Fixes: 3fc5ca2 ("kni: initial import")

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
Reviewed-by: Gavin Hu <Gavin.Hu@arm.com>
---
 kernel/linux/kni/kni_fifo.h                              | 16 ++++++++++------
 .../linuxapp/eal/include/exec-env/rte_kni_common.h       |  1 +
 2 files changed, 11 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/kernel/linux/kni/kni_fifo.h b/kernel/linux/kni/kni_fifo.h
index 9a4762d..2cb3a4a 100644
--- a/kernel/linux/kni/kni_fifo.h
+++ b/kernel/linux/kni/kni_fifo.h
@@ -16,7 +16,7 @@  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++) {
@@ -27,7 +27,7 @@  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;
 }
@@ -40,7 +40,7 @@  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)
@@ -49,7 +49,7 @@  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;
 }
@@ -60,7 +60,9 @@  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);
 }
 
 /**
@@ -69,7 +71,9 @@  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);
 }
 
 #endif /* _KNI_FIFO_H_ */
diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
index cfa9448..58e8533 100644
--- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
+++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
@@ -8,6 +8,7 @@ 
 
 #ifdef __KERNEL__
 #include <linux/if.h>
+#include <asm/barrier.h>
 #define RTE_STD_C11
 #else
 #include <rte_common.h>