On Tue, May 10, 2022 at 10:22:45PM +0800, Wan Jiabing wrote:
> Calling __phy_read() might return a negative error code. Use 'int'
> to declare variables which call __phy_read() and also add error check
> for them.
>
> The numerous callers of vsc8584_macsec_phy_read() don't expect it to
> fail. So don't return the error code from __phy_read(), but also don't
> return random values if it does fail.
>
> Fixes: fa164e40c53b ("net: phy: mscc: split the driver into separate files")
> Signed-off-by: Wan Jiabing <[email protected]>
> ---
> Changelog:
> v2:
> - Sort variable declaration and add a detailed comment.
> ---
> drivers/net/phy/mscc/mscc_macsec.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/phy/mscc/mscc_macsec.c b/drivers/net/phy/mscc/mscc_macsec.c
> index b7b2521c73fb..58ad11a697b6 100644
> --- a/drivers/net/phy/mscc/mscc_macsec.c
> +++ b/drivers/net/phy/mscc/mscc_macsec.c
> @@ -22,9 +22,9 @@
> static u32 vsc8584_macsec_phy_read(struct phy_device *phydev,
> enum macsec_bank bank, u32 reg)
> {
> - u32 val, val_l = 0, val_h = 0;
> + int rc, val, val_l, val_h;
> unsigned long deadline;
> - int rc;
> + u32 ret = 0;
>
> rc = phy_select_page(phydev, MSCC_PHY_PAGE_MACSEC);
> if (rc < 0)
> @@ -47,15 +47,20 @@ static u32 vsc8584_macsec_phy_read(struct phy_device *phydev,
> deadline = jiffies + msecs_to_jiffies(PROC_CMD_NCOMPLETED_TIMEOUT_MS);
> do {
> val = __phy_read(phydev, MSCC_EXT_PAGE_MACSEC_19);
> + if (val < 0)
> + goto failed;
> } while (time_before(jiffies, deadline) && !(val & MSCC_PHY_MACSEC_19_CMD));
>
> val_l = __phy_read(phydev, MSCC_EXT_PAGE_MACSEC_17);
> val_h = __phy_read(phydev, MSCC_EXT_PAGE_MACSEC_18);
>
> + if (val_l > 0 && val_h > 0)
> + ret = (val_h << 16) | val_l;
> +
> failed:
> phy_restore_page(phydev, rc, rc);
>
> - return (val_h << 16) | val_l;
> + return ret;
> }
This is still wrong - phy_restore_page() can fail to retore the page.
It's rather unfortunate that you need to return a u32, where the
high values become negative ints, which means you can't use
phy_restore_page() as it's supposed to be used.
If you fail to read from the PHY, is returning zero acceptable?
I think what you should be doing at the very least is:
rc = phy_select_page(phydev, MSCC_PHY_PAGE_MACSEC);
if (rc < 0)
goto failed;
rc = __phy_write(phydev, MSCC_EXT_PAGE_MACSEC_20, ...);
if (rc < 0)
goto failed;
...
rc = __phy_write(phydev, MSCC_EXT_PAGE_MACSEC_19, ...);
if (rc < 0)
goto failed;
...
do {
val = __phy_read(phydev, MSCC_EXT_PAGE_MACSEC_19);
if (val < 0) {
rc = val;
goto failed;
}
} while (...);
val_l = __phy_read(phydev, MSCC_EXT_PAGE_MACSEC_17);
if (val_l < 0) {
rc = val_l;
goto failed;
}
val_h = __phy_read(phydev, MSCC_EXT_PAGE_MACSEC_18);
if (val_h < 0)
rc = val_h;
failed:
rc = phy_restore_page(phgydev, rc, 0);
return rc < 0 ? 0 : val_h << 16 | val_l;
Which means that if any of the PHY IO functions fail at any point, this
returns zero.
--
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