[PATCH 1/2] net: ax88796c: Fix clang -Wimplicit-fallthrough in ax88796c_set_mac()

Clang warns:

drivers/net/ethernet/asix/ax88796c_main.c:696:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case SPEED_10:
        ^
drivers/net/ethernet/asix/ax88796c_main.c:696:2: note: insert 'break;' to avoid fall-through
        case SPEED_10:
        ^
        break;
drivers/net/ethernet/asix/ax88796c_main.c:706:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case DUPLEX_HALF:
        ^
drivers/net/ethernet/asix/ax88796c_main.c:706:2: note: insert 'break;' to avoid fall-through
        case DUPLEX_HALF:
        ^
        break;

Clang is a little more pedantic than GCC, which permits implicit
fallthroughs to cases that contain just break or return. Clang's version
is more in line with the kernel's own stance in deprecated.rst, which
states that all switch/case blocks must end in either break,
fallthrough, continue, goto, or return. Add the missing breaks to fix
the warning.

Link: https://github.com/ClangBuiltLinux/linux/issues/1491
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/net/ethernet/asix/ax88796c_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/asix/ax88796c_main.c b/drivers/net/ethernet/asix/ax88796c_main.c
index cfc597f72e3d..cf0f96f93f3b 100644
--- a/drivers/net/ethernet/asix/ax88796c_main.c
+++ b/drivers/net/ethernet/asix/ax88796c_main.c

@@ -693,6 +693,7 @@ static void ax88796c_set_mac(struct  ax88796c_device *ax_local)
 	switch (ax_local->speed) {
 	case SPEED_100:
 		maccr |= MACCR_SPEED_100;
+		break;
 	case SPEED_10:
 	case SPEED_UNKNOWN:
 		break;

@@ -703,6 +704,7 @@ static void ax88796c_set_mac(struct  ax88796c_device *ax_local)
 	switch (ax_local->duplex) {
 	case DUPLEX_FULL:
 		maccr |= MACCR_SPEED_100;
+		break;
 	case DUPLEX_HALF:
 	case DUPLEX_UNKNOWN:
 		break;

base-commit: dcd63d4326802cec525de2a4775019849958125c
-- 
2.33.1.637.gf443b226ca

Clang warns:

drivers/net/ethernet/asix/ax88796c_main.c:851:24: error: address of
array 'ax_local->phydev->advertising' will always evaluate to 'true'
[-Werror,-Wpointer-bool-conversion]
        if (ax_local->phydev->advertising &&
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~ ~~

advertising cannot be NULL here if ax_local is not NULL, which cannot
happen due to the check in ax88796c_probe(). Remove the check.

Link: https://github.com/ClangBuiltLinux/linux/issues/1492
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/net/ethernet/asix/ax88796c_main.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/asix/ax88796c_main.c b/drivers/net/ethernet/asix/ax88796c_main.c
index cf0f96f93f3b..528a0c43540b 100644
--- a/drivers/net/ethernet/asix/ax88796c_main.c
+++ b/drivers/net/ethernet/asix/ax88796c_main.c

@@ -850,11 +850,10 @@ ax88796c_open(struct net_device *ndev)
 	/* Setup flow-control configuration */
 	phy_support_asym_pause(ax_local->phydev);
 
-	if (ax_local->phydev->advertising &&
-	    (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
-			       ax_local->phydev->advertising) ||
-	     linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
-			       ax_local->phydev->advertising)))
+	if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
+			      ax_local->phydev->advertising) ||
+	    linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
+			      ax_local->phydev->advertising))
 		fc |= AX_FC_ANEG;
 
 	fc |= linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,

-- 
2.33.1.637.gf443b226ca

Hello:

This series was applied to netdev/net-next.git (master)
by David S. Miller [off-list ref]:

On Mon, 25 Oct 2021 14:12:38 -0700 you wrote:

Clang warns:

drivers/net/ethernet/asix/ax88796c_main.c:696:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case SPEED_10:
        ^
drivers/net/ethernet/asix/ax88796c_main.c:696:2: note: insert 'break;' to avoid fall-through
        case SPEED_10:
        ^
        break;
drivers/net/ethernet/asix/ax88796c_main.c:706:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case DUPLEX_HALF:
        ^
drivers/net/ethernet/asix/ax88796c_main.c:706:2: note: insert 'break;' to avoid fall-through
        case DUPLEX_HALF:
        ^
        break;

[...]

Here is the summary with links:
  - [1/2] net: ax88796c: Fix clang -Wimplicit-fallthrough in ax88796c_set_mac()
    https://git.kernel.org/netdev/net-next/c/3c5548812a0c
  - [2/2] net: ax88796c: Remove pointless check in ax88796c_open()
    https://git.kernel.org/netdev/net-next/c/971f5c4079ed

You are awesome, thank you!
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