| Message ID | 20210727082147.270734-1-yoshihiro.shimoda.uh@renesas.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | ravb and sh_eth: Fix descriptor counters' conditions | expand |
Hi all, > From: Yoshihiro Shimoda, Sent: Tuesday, July 27, 2021 5:22 PM > > When we change the type of {cur,dirty}_tx from u32 to u8, we can > reproduce this issue easily. I'm afraid but I would like to recall this patch series because the original code didn't have any issue around these counters so that the patch series should not be applied. For just a record, I tried to write why I misunderstood these counters are incorrect below: - I got a report locally about an issue happen when the system sends/receives data in long time transfer - So, I doubted these counters' overflow. - To reproduce the issue quickly, I changed the type from u32 to u8. - And then, the following condition will not work correctly (as I mentioned on the patch). for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) { --- [1] - Also, I found if we used "> 0U" instead of "0", the issue disappeared. for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0U; priv->dirty_tx[q]++) { --- [2] ~~ - However, today I got a report from our team member locally. The object code of the get_num_desc() is just "from - subtract". - If we use u32 as the original code, I realized the object codes between [1] and [2] are the same. - Also, I realized just priv->cur_tx[q] - priv->dirty_tx[q] is no problem. - So, I would like to recall this patch series. Best regards, Yoshihiro Shimoda
When we change the type of {cur,dirty}_tx from u32 to u8, we can reproduce this issue easily. Yoshihiro Shimoda (2): ravb: Fix descriptor counters' conditions sh_eth: Fix descriptor counters' conditions drivers/net/ethernet/renesas/ravb_main.c | 22 +++++++++++++++------- drivers/net/ethernet/renesas/sh_eth.c | 16 ++++++++++++---- 2 files changed, 27 insertions(+), 11 deletions(-)