[PATCH 2/2] net: encx24j600: Fix invalid logic in reading of MISTAT register

From: Valentina Goncharenko
Date: Thu Dec 01 2022 - 12:34:37 EST


A loop for reading MISTAT register continues while regmap_read() fails
and (mistat & BUSY), but if regmap_read() fails a value of mistat is
undefined.

The patch proposes to check for BUSY flag only when regmap_read()
succeed. Compile test only.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: d70e53262f5c ("net: Microchip encx24j600 driver")
Signed-off-by: Valentina Goncharenko <goncharenko.vp@xxxxxxxxx>
---
drivers/net/ethernet/microchip/encx24j600-regmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/microchip/encx24j600-regmap.c b/drivers/net/ethernet/microchip/encx24j600-regmap.c
index 2e337c7a5773..5693784eec5b 100644
--- a/drivers/net/ethernet/microchip/encx24j600-regmap.c
+++ b/drivers/net/ethernet/microchip/encx24j600-regmap.c
@@ -359,7 +359,7 @@ static int regmap_encx24j600_phy_reg_read(void *context, unsigned int reg,
goto err_out;

usleep_range(26, 100);
- while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
+ while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
(mistat & BUSY))
cpu_relax();

@@ -397,7 +397,7 @@ static int regmap_encx24j600_phy_reg_write(void *context, unsigned int reg,
goto err_out;

usleep_range(26, 100);
- while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
+ while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
(mistat & BUSY))
cpu_relax();

--
2.25.1