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kni: fix FIFO synchronization

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With existing code in kni_fifo_put, rx_q values are not being updated
before updating fifo_write. While reading rx_q in kni_net_rx_normal,
This is causing the sync issue on other core. The same situation happens
in kni_fifo_get as well.

So syncing the values by adding memory barriers to make sure the values
being synced before updating fifo_write and fifo_read.

Fixes: 3fc5ca2f6352 ("kni: initial import")
Cc: stable@dpdk.org

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>
Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com>
Reviewed-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
This commit is contained in:
Phil Yang 2018-10-08 17:11:44 +08:00 committed by Thomas Monjalon
parent ede56cc18d
commit 0b05abe7bf
1 changed files with 10 additions and 2 deletions
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12
lib/librte_kni/rte_kni_fifo.h
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@ -28,8 +28,9 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
{
unsigned i = 0;
unsigned fifo_write = fifo->write;
unsigned fifo_read = fifo->read;
unsigned new_write = fifo_write;
rte_smp_rmb();
unsigned fifo_read = fifo->read;
for (i = 0; i < num; i++) {
new_write = (new_write + 1) & (fifo->len - 1);
@ -39,6 +40,7 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
fifo->buffer[fifo_write] = data[i];
fifo_write = new_write;
}
rte_smp_wmb();
fifo->write = fifo_write;
return i;
}
@ -51,7 +53,9 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)
{
unsigned i = 0;
unsigned new_read = fifo->read;
rte_smp_rmb();
unsigned fifo_write = fifo->write;
for (i = 0; i < num; i++) {
if (new_read == fifo_write)
break;
@ -59,6 +63,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)
data[i] = fifo->buffer[new_read];
new_read = (new_read + 1) & (fifo->len - 1);
}
rte_smp_rmb();
fifo->read = new_read;
return i;
}
@ -69,5 +74,8 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)
static inline uint32_t
kni_fifo_count(struct rte_kni_fifo *fifo)
{
return (fifo->len + fifo->write - fifo->read) & (fifo->len - 1);
unsigned fifo_write = fifo->write;
rte_smp_rmb();
unsigned fifo_read = fifo->read;
return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1);
}