| Message ID | ac97150d7ba16b2145edfe77e377bd5e467735ff.1624013456.git.esben@geanix.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 28d9fab458b16bcd83f9dd07ede3d585c3e1a69e |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [1/4] net: ll_temac: Make sure to free skb when it is completely used | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | warning | Series does not have a cover letter |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | success | CCed 10 of 10 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 29 this patch: 29 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 37 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 29 this patch: 29 |
| netdev/header_inline | success | Link |
diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c index e82f162cd80c..9797aa3221d1 100644 --- a/drivers/net/ethernet/xilinx/ll_temac_main.c +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c @@ -774,12 +774,15 @@ static void temac_start_xmit_done(struct net_device *ndev) stat = be32_to_cpu(cur_p->app0); while (stat & STS_CTRL_APP0_CMPLT) { + /* Make sure that the other fields are read after bd is + * released by dma + */ + rmb(); dma_unmap_single(ndev->dev.parent, be32_to_cpu(cur_p->phys), be32_to_cpu(cur_p->len), DMA_TO_DEVICE); skb = (struct sk_buff *)ptr_from_txbd(cur_p); if (skb) dev_consume_skb_irq(skb); - cur_p->app0 = 0; cur_p->app1 = 0; cur_p->app2 = 0; cur_p->app3 = 0; @@ -788,6 +791,12 @@ static void temac_start_xmit_done(struct net_device *ndev) ndev->stats.tx_packets++; ndev->stats.tx_bytes += be32_to_cpu(cur_p->len); + /* app0 must be visible last, as it is used to flag + * availability of the bd + */ + smp_mb(); + cur_p->app0 = 0; + lp->tx_bd_ci++; if (lp->tx_bd_ci >= lp->tx_bd_num) lp->tx_bd_ci = 0; @@ -814,6 +823,9 @@ static inline int temac_check_tx_bd_space(struct temac_local *lp, int num_frag) if (cur_p->app0) return NETDEV_TX_BUSY; + /* Make sure to read next bd app0 after this one */ + rmb(); + tail++; if (tail >= lp->tx_bd_num) tail = 0;
Add a couple of memory-barriers to ensure correct ordering of read/write access to TX BDs. In xmit_done, we should ensure that reading the additional BD fields are only done after STS_CTRL_APP0_CMPLT bit is set. When xmit_done marks the BD as free by setting APP0=0, we need to ensure that the other BD fields are reset first, so we avoid racing with the xmit path, which writes to the same fields. Finally, making sure to read APP0 of next BD after the current BD, ensures that we see all available buffers. Signed-off-by: Esben Haabendal <esben@geanix.com> --- drivers/net/ethernet/xilinx/ll_temac_main.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)