Messages in this thread | | | From | Colin Ian King <> | Subject | issue with unreachable code in net sxgbe driver | Date | Fri, 9 Jul 2021 15:03:32 +0100 |
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Hi,
Static analysis with Coverity has detected several occurrences of dead code in the sxgbe driver in function sxgbe_mtl_init. The issue was introduced with the following commit:
commit 1edb9ca69e8a7988900fc0283e10550b5592164d Author: Siva Reddy <siva.kallam@samsung.com> Date: Tue Mar 25 12:10:54 2014 -0700
net: sxgbe: add basic framework for Samsung 10Gb ethernet driver
The analysis is as follows:
20static void sxgbe_mtl_init(void __iomem *ioaddr, unsigned int etsalg, 21 unsigned int raa) 22{ 23 u32 reg_val; 24 25 reg_val = readl(ioaddr + SXGBE_MTL_OP_MODE_REG); 26 reg_val &= ETS_RST; 27 28 /* ETS Algorith */ 29 switch (etsalg & SXGBE_MTL_OPMODE_ESTMASK) {
Logically dead code (DEADCODE)
30 case ETS_WRR: 31 reg_val &= ETS_WRR; 32 break;
Logically dead code (DEADCODE)
33 case ETS_WFQ: 34 reg_val |= ETS_WFQ; 35 break;
Logically dead code (DEADCODE)
36 case ETS_DWRR: 37 reg_val |= ETS_DWRR; 38 break; 39 }
SXGBE_MTL_OPMODE_ESTMASK is defined as 0x03 ETS_WRR is 0xFFFFFF9F ETS_WFQ is 0x00000020 ETS_DWRR is 0x00000040
so the masking of etsalg & SXGBE_MTL_OPMODE_ESTMASK will never match any of the ETS_* values, hence the dead code.
40 writel(reg_val, ioaddr + SXGBE_MTL_OP_MODE_REG); 41 42 switch (raa & SXGBE_MTL_OPMODE_RAAMASK) {
Logically dead code (DEADCODE)
43 case RAA_SP: 44 reg_val &= RAA_SP; 45 break;
Logically dead code (DEADCODE)
46 case RAA_WSP: 47 reg_val |= RAA_WSP; 48 break; 49 } 50 writel(reg_val, ioaddr + SXGBE_MTL_OP_MODE_REG); 51}
SXGBE_MTL_OPMODE_RAAMASK is defined as 0x1 RAA_SP is 0xFFFFFFFB RAA_WSP is 0x00000004
so masking of raa & SXGBE_MTL_OPMODE_RAAMASK will never match any of the RAA_* values, hence the dead code.
I don't think this is intentional. Not sure how to fix this hence I'm reporting this issue.
Regards,
Colin
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