net: encx24j600: Fix invalid logic in reading of MISTAT register

[ Upstream commit 25f427ac7b8d89b0259f86c0c6407b329df742b2 ]

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@ispras.ru>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit ea113b570eeed36801504b4667f2b8d6741f9f12)
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/drivers/net/ethernet/microchip/encx24j600-regmap.c b/drivers/net/ethernet/microchip/encx24j600-regmap.c
index 2e337c7a57736d1bf3f441d7f922b418094b8217..5693784eec5bc0a73ae4bf60b096ba999eff9233 100644 (file)
--- 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();