Thread (27 messages) flat view 27 messages, 9 authors, 2021-08-04

Re: [PATCH 1/2] igc: don't rd/wr iomem when PCI is removed

From: Dave Airlie <airlied@gmail.com>
Date: 2021-07-05 07:47:18
Also in: intel-wired-lan, lkml

On Fri, 2 Jul 2021 at 14:53, Aaron Ma [off-list ref] wrote:
Check PCI state when rd/wr iomem.
Implement wr32 function as rd32 too.

When unplug TBT dock with i225, rd/wr PCI iomem will cause error log:
Trace:
BUG: unable to handle page fault for address: 000000000000b604
Oops: 0000 [#1] SMP NOPTI
RIP: 0010:igc_rd32+0x1c/0x90 [igc]
Call Trace:
igc_ptp_suspend+0x6c/0xa0 [igc]
igc_ptp_stop+0x12/0x50 [igc]
igc_remove+0x7f/0x1c0 [igc]
pci_device_remove+0x3e/0xb0
__device_release_driver+0x181/0x240

Signed-off-by: Aaron Ma <redacted>
---
Drive-by, but won't this add a lot of overhead on every register
access? has this been benchmarked with lots of small network transfers
or anything?

Dave.

quoted hunk ↗ jump to hunk
 drivers/net/ethernet/intel/igc/igc_main.c | 16 ++++++++++++++++
 drivers/net/ethernet/intel/igc/igc_regs.h |  7 ++-----
 2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index f1adf154ec4a..606b72cb6193 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -5292,6 +5292,10 @@ u32 igc_rd32(struct igc_hw *hw, u32 reg)
        u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr);
        u32 value = 0;

+       if (igc->pdev &&
+               igc->pdev->error_state == pci_channel_io_perm_failure)
+               return 0;
+
        value = readl(&hw_addr[reg]);

        /* reads should not return all F's */
@@ -5308,6 +5312,18 @@ u32 igc_rd32(struct igc_hw *hw, u32 reg)
        return value;
 }

+void igc_wr32(struct igc_hw *hw, u32 reg, u32 val)
+{
+       struct igc_adapter *igc = container_of(hw, struct igc_adapter, hw);
+       u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr);
+
+       if (igc->pdev &&
+               igc->pdev->error_state == pci_channel_io_perm_failure)
+               return;
+
+       writel((val), &hw_addr[(reg)]);
+}
+
 int igc_set_spd_dplx(struct igc_adapter *adapter, u32 spd, u8 dplx)
 {
        struct igc_mac_info *mac = &adapter->hw.mac;
diff --git a/drivers/net/ethernet/intel/igc/igc_regs.h b/drivers/net/ethernet/intel/igc/igc_regs.h
index cc174853554b..eb4be87d0e8b 100644
--- a/drivers/net/ethernet/intel/igc/igc_regs.h
+++ b/drivers/net/ethernet/intel/igc/igc_regs.h
@@ -260,13 +260,10 @@ struct igc_hw;
 u32 igc_rd32(struct igc_hw *hw, u32 reg);

 /* write operations, indexed using DWORDS */
-#define wr32(reg, val) \
-do { \
-       u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \
-       writel((val), &hw_addr[(reg)]); \
-} while (0)
+void igc_wr32(struct igc_hw *hw, u32 reg, u32 val);

 #define rd32(reg) (igc_rd32(hw, reg))
+#define wr32(reg, val) (igc_wr32(hw, reg, val))

 #define wrfl() ((void)rd32(IGC_STATUS))

--
2.30.2
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