[PATCH net-next-2.6] sfc: Replace enum efx_fc_type with a 'bitwise' type

[Ben Hutchings <bhutchings@solarflare.com>]

gcc 4.5 doesn't like enumerators as flags, and neither does davem.
Replace the enumerated type with a 'bitwise' type alias which makes it
clear where these flags are being used and allows sparse to validate
their use.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
You wrote:
> What part of "get rid of the enum" is so hard to understand?
>
> I'll say it again: Please get rid of the enum efx_fc_type

OK, done.

> You can define bit positions if you like, because those will
> be used as a proper enum, as unique bit positions within
> a set of bits.  Then you can define macros as (1 << XXX)

But that seems to result in discarding all type information for the
flags. I would prefer to improve type checking.

Ben.

 drivers/net/sfc/efx.c        |    2 +-
 drivers/net/sfc/efx.h        |    2 +-
 drivers/net/sfc/ethtool.c    |    2 +-
 drivers/net/sfc/mdio_10g.c   |   13 ++++++++-----
 drivers/net/sfc/mdio_10g.h   |    2 +-
 drivers/net/sfc/net_driver.h |   15 +++++++--------
 6 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 05502b3..f840879 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -833,7 +833,7 @@ void efx_link_set_advertising(struct efx_nic *efx, u32 advertising)
 	}
 }
 
-void efx_link_set_wanted_fc(struct efx_nic *efx, enum efx_fc_type wanted_fc)
+void efx_link_set_wanted_fc(struct efx_nic *efx, efx_fc_mode wanted_fc)
 {
 	efx->wanted_fc = wanted_fc;
 	if (efx->link_advertising) {
diff --git a/drivers/net/sfc/efx.h b/drivers/net/sfc/efx.h
index 3d83a1f..242d68b 100644
--- a/drivers/net/sfc/efx.h
+++ b/drivers/net/sfc/efx.h
@@ -142,6 +142,6 @@ static inline void efx_schedule_channel(struct efx_channel *channel)
 
 extern void efx_link_status_changed(struct efx_nic *efx);
 extern void efx_link_set_advertising(struct efx_nic *efx, u32);
-extern void efx_link_set_wanted_fc(struct efx_nic *efx, enum efx_fc_type);
+extern void efx_link_set_wanted_fc(struct efx_nic *efx, efx_fc_mode);
 
 #endif /* EFX_EFX_H */
diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index 348437a..114829d 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -698,7 +698,7 @@ static int efx_ethtool_set_pauseparam(struct net_device *net_dev,
 				      struct ethtool_pauseparam *pause)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
-	enum efx_fc_type wanted_fc, old_fc;
+	efx_fc_mode wanted_fc, old_fc;
 	u32 old_adv;
 	bool reset;
 	int rc = 0;
diff --git a/drivers/net/sfc/mdio_10g.c b/drivers/net/sfc/mdio_10g.c
index 7115914..9be5da6 100644
--- a/drivers/net/sfc/mdio_10g.c
+++ b/drivers/net/sfc/mdio_10g.c
@@ -284,18 +284,21 @@ void efx_mdio_an_reconfigure(struct efx_nic *efx)
 	efx_mdio_write(efx, MDIO_MMD_AN, MDIO_CTRL1, reg);
 }
 
-enum efx_fc_type efx_mdio_get_pause(struct efx_nic *efx)
+efx_fc_mode efx_mdio_get_pause(struct efx_nic *efx)
 {
-	BUILD_BUG_ON(EFX_FC_AUTO & (EFX_FC_RX | EFX_FC_TX));
+	BUILD_BUG_ON((__force u8)EFX_FC_TX != FLOW_CTRL_TX);
+	BUILD_BUG_ON((__force u8)EFX_FC_RX != FLOW_CTRL_RX);
 
 	if (!(efx->wanted_fc & EFX_FC_AUTO))
 		return efx->wanted_fc;
 
 	WARN_ON(!(efx->mdio.mmds & MDIO_DEVS_AN));
 
-	return mii_resolve_flowctrl_fdx(
-		mii_advertise_flowctrl(efx->wanted_fc),
-		efx_mdio_read(efx, MDIO_MMD_AN, MDIO_AN_LPA));
+	return (__force efx_fc_mode)
+		mii_resolve_flowctrl_fdx(
+			mii_advertise_flowctrl((__force int)
+					       (efx->wanted_fc & ~EFX_FC_AUTO)),
+			efx_mdio_read(efx, MDIO_MMD_AN, MDIO_AN_LPA));
 }
 
 int efx_mdio_test_alive(struct efx_nic *efx)
diff --git a/drivers/net/sfc/mdio_10g.h b/drivers/net/sfc/mdio_10g.h
index df07039..1616b13 100644
--- a/drivers/net/sfc/mdio_10g.h
+++ b/drivers/net/sfc/mdio_10g.h
@@ -92,7 +92,7 @@ extern void efx_mdio_an_reconfigure(struct efx_nic *efx);
 /* Get pause parameters from AN if available (otherwise return
  * requested pause parameters)
  */
-enum efx_fc_type efx_mdio_get_pause(struct efx_nic *efx);
+extern efx_fc_mode efx_mdio_get_pause(struct efx_nic *efx);
 
 /* Wait for specified MMDs to exit reset within a timeout */
 extern int efx_mdio_wait_reset_mmds(struct efx_nic *efx,
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index ce9697b..1c29775 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -448,12 +448,11 @@ enum nic_state {
 /* Forward declaration */
 struct efx_nic;
 
-/* Pseudo bit-mask flow control field */
-enum efx_fc_type {
-	EFX_FC_RX = FLOW_CTRL_RX,
-	EFX_FC_TX = FLOW_CTRL_TX,
-	EFX_FC_AUTO = 4,
-};
+/* Flow control flags */
+typedef unsigned int __bitwise efx_fc_mode;
+#define EFX_FC_TX	((__force efx_fc_mode) 1)
+#define EFX_FC_RX	((__force efx_fc_mode) 2)
+#define EFX_FC_AUTO	((__force efx_fc_mode) 4)
 
 /**
  * struct efx_link_state - Current state of the link
@@ -465,7 +464,7 @@ enum efx_fc_type {
 struct efx_link_state {
 	bool up;
 	bool fd;
-	enum efx_fc_type fc;
+	efx_fc_mode fc;
 	unsigned int speed;
 };
 
@@ -784,7 +783,7 @@ struct efx_nic {
 
 	bool promiscuous;
 	union efx_multicast_hash multicast_hash;
-	enum efx_fc_type wanted_fc;
+	efx_fc_mode wanted_fc;
 
 	atomic_t rx_reset;
 	enum efx_loopback_mode loopback_mode;
-- 
1.7.4


-- 
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.