ethtool: add infrastructure for centralized checking of coalescing parameters

Linux supports 22 different interrupt coalescing parameters.
No driver implements them all. Some drivers just ignore the
ones they don't support, while others have to carry a long
list of checks to reject unsupported settings.

To simplify the drivers add the ability to specify inside
ethtool_ops which parameters are supported and let the core
reject attempts to set any other one.

This commit makes the mechanism an opt-in, only drivers which
set ethtool_opts->coalesce_types to a non-zero value will have
the checks enforced.

The same mask is used for global and per queue settings.

v3: - move the (temporary) check if driver defines types
      earlier (Michal)
    - rename used_types -> nonzero_params, and
      coalesce_types -> supported_coalesce_params (Alex)
    - use EOPNOTSUPP instead of EINVAL (Andrew, Michal)

Leaving the long series of ifs for now, it seems nice to
be able to grep for the field and flag names. This will
probably have to be revisited once netlink support lands.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/ethtool.h

@@ -177,8 +177,44 @@ void ethtool_convert_legacy_u32_to_link_mode(unsigned long *dst,
 bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
 				     const unsigned long *src);
 
+#define ETHTOOL_COALESCE_RX_USECS		BIT(0)
+#define ETHTOOL_COALESCE_RX_MAX_FRAMES		BIT(1)
+#define ETHTOOL_COALESCE_RX_USECS_IRQ		BIT(2)
+#define ETHTOOL_COALESCE_RX_MAX_FRAMES_IRQ	BIT(3)
+#define ETHTOOL_COALESCE_TX_USECS		BIT(4)
+#define ETHTOOL_COALESCE_TX_MAX_FRAMES		BIT(5)
+#define ETHTOOL_COALESCE_TX_USECS_IRQ		BIT(6)
+#define ETHTOOL_COALESCE_TX_MAX_FRAMES_IRQ	BIT(7)
+#define ETHTOOL_COALESCE_STATS_BLOCK_USECS	BIT(8)
+#define ETHTOOL_COALESCE_USE_ADAPTIVE_RX	BIT(9)
+#define ETHTOOL_COALESCE_USE_ADAPTIVE_TX	BIT(10)
+#define ETHTOOL_COALESCE_PKT_RATE_LOW		BIT(11)
+#define ETHTOOL_COALESCE_RX_USECS_LOW		BIT(12)
+#define ETHTOOL_COALESCE_RX_MAX_FRAMES_LOW	BIT(13)
+#define ETHTOOL_COALESCE_TX_USECS_LOW		BIT(14)
+#define ETHTOOL_COALESCE_TX_MAX_FRAMES_LOW	BIT(15)
+#define ETHTOOL_COALESCE_PKT_RATE_HIGH		BIT(16)
+#define ETHTOOL_COALESCE_RX_USECS_HIGH		BIT(17)
+#define ETHTOOL_COALESCE_RX_MAX_FRAMES_HIGH	BIT(18)
+#define ETHTOOL_COALESCE_TX_USECS_HIGH		BIT(19)
+#define ETHTOOL_COALESCE_TX_MAX_FRAMES_HIGH	BIT(20)
+#define ETHTOOL_COALESCE_RATE_SAMPLE_INTERVAL	BIT(21)
+
+#define ETHTOOL_COALESCE_USECS						\
+	(ETHTOOL_COALESCE_RX_USECS | ETHTOOL_COALESCE_TX_USECS)
+#define ETHTOOL_COALESCE_MAX_FRAMES					\
+	(ETHTOOL_COALESCE_RX_MAX_FRAMES | ETHTOOL_COALESCE_TX_MAX_FRAMES)
+#define ETHTOOL_COALESCE_USECS_IRQ					\
+	(ETHTOOL_COALESCE_RX_USECS_IRQ | ETHTOOL_COALESCE_TX_USECS_IRQ)
+#define ETHTOOL_COALESCE_MAX_FRAMES_IRQ		\
+	(ETHTOOL_COALESCE_RX_MAX_FRAMES_IRQ |	\
+	 ETHTOOL_COALESCE_TX_MAX_FRAMES_IRQ)
+#define ETHTOOL_COALESCE_USE_ADAPTIVE					\
+	(ETHTOOL_COALESCE_USE_ADAPTIVE_RX | ETHTOOL_COALESCE_USE_ADAPTIVE_TX)
+
 /**
  * struct ethtool_ops - optional netdev operations
+ * @supported_coalesce_params: supported types of interrupt coalescing.
  * @get_drvinfo: Report driver/device information.  Should only set the
  *	@driver, @version, @fw_version and @bus_info fields.  If not
  *	implemented, the @driver and @bus_info fields will be filled in
@@ -207,8 +243,9 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
  *	or zero.
  * @get_coalesce: Get interrupt coalescing parameters.  Returns a negative
  *	error code or zero.
- * @set_coalesce: Set interrupt coalescing parameters.  Returns a negative
- *	error code or zero.
+ * @set_coalesce: Set interrupt coalescing parameters.  Supported coalescing
+ *	types should be set in @supported_coalesce_params.
+ *	Returns a negative error code or zero.
  * @get_ringparam: Report ring sizes
  * @set_ringparam: Set ring sizes.  Returns a negative error code or zero.
  * @get_pauseparam: Report pause parameters
@@ -292,7 +329,8 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
  * @set_per_queue_coalesce: Set interrupt coalescing parameters per queue.
  *	It must check that the given queue number is valid. If neither a RX nor
  *	a TX queue has this number, return -EINVAL. If only a RX queue or a TX
- *	queue has this number, ignore the inapplicable fields.
+ *	queue has this number, ignore the inapplicable fields. Supported
+ *	coalescing types should be set in @supported_coalesce_params.
  *	Returns a negative error code or zero.
  * @get_link_ksettings: Get various device settings including Ethernet link
  *	settings. The %cmd and %link_mode_masks_nwords fields should be
@@ -323,6 +361,7 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
  * of the generic netdev features interface.
  */
 struct ethtool_ops {
+	u32	supported_coalesce_params;
 	void	(*get_drvinfo)(struct net_device *, struct ethtool_drvinfo *);
 	int	(*get_regs_len)(struct net_device *);
 	void	(*get_regs)(struct net_device *, struct ethtool_regs *, void *);

net/ethtool/ioctl.c

@@ -1544,6 +1544,64 @@ static noinline_for_stack int ethtool_get_coalesce(struct net_device *dev,
 	return 0;
 }
 
+static bool
+ethtool_set_coalesce_supported(struct net_device *dev,
+			       struct ethtool_coalesce *coalesce)
+{
+	u32 supported_params = dev->ethtool_ops->supported_coalesce_params;
+	u32 nonzero_params = 0;
+
+	if (!supported_params)
+		return true;
+
+	if (coalesce->rx_coalesce_usecs)
+		nonzero_params |= ETHTOOL_COALESCE_RX_USECS;
+	if (coalesce->rx_max_coalesced_frames)
+		nonzero_params |= ETHTOOL_COALESCE_RX_MAX_FRAMES;
+	if (coalesce->rx_coalesce_usecs_irq)
+		nonzero_params |= ETHTOOL_COALESCE_RX_USECS_IRQ;
+	if (coalesce->rx_max_coalesced_frames_irq)
+		nonzero_params |= ETHTOOL_COALESCE_RX_MAX_FRAMES_IRQ;
+	if (coalesce->tx_coalesce_usecs)
+		nonzero_params |= ETHTOOL_COALESCE_TX_USECS;
+	if (coalesce->tx_max_coalesced_frames)
+		nonzero_params |= ETHTOOL_COALESCE_TX_MAX_FRAMES;
+	if (coalesce->tx_coalesce_usecs_irq)
+		nonzero_params |= ETHTOOL_COALESCE_TX_USECS_IRQ;
+	if (coalesce->tx_max_coalesced_frames_irq)
+		nonzero_params |= ETHTOOL_COALESCE_TX_MAX_FRAMES_IRQ;
+	if (coalesce->stats_block_coalesce_usecs)
+		nonzero_params |= ETHTOOL_COALESCE_STATS_BLOCK_USECS;
+	if (coalesce->use_adaptive_rx_coalesce)
+		nonzero_params |= ETHTOOL_COALESCE_USE_ADAPTIVE_RX;
+	if (coalesce->use_adaptive_tx_coalesce)
+		nonzero_params |= ETHTOOL_COALESCE_USE_ADAPTIVE_TX;
+	if (coalesce->pkt_rate_low)
+		nonzero_params |= ETHTOOL_COALESCE_PKT_RATE_LOW;
+	if (coalesce->rx_coalesce_usecs_low)
+		nonzero_params |= ETHTOOL_COALESCE_RX_USECS_LOW;
+	if (coalesce->rx_max_coalesced_frames_low)
+		nonzero_params |= ETHTOOL_COALESCE_RX_MAX_FRAMES_LOW;
+	if (coalesce->tx_coalesce_usecs_low)
+		nonzero_params |= ETHTOOL_COALESCE_TX_USECS_LOW;
+	if (coalesce->tx_max_coalesced_frames_low)
+		nonzero_params |= ETHTOOL_COALESCE_TX_MAX_FRAMES_LOW;
+	if (coalesce->pkt_rate_high)
+		nonzero_params |= ETHTOOL_COALESCE_PKT_RATE_HIGH;
+	if (coalesce->rx_coalesce_usecs_high)
+		nonzero_params |= ETHTOOL_COALESCE_RX_USECS_HIGH;
+	if (coalesce->rx_max_coalesced_frames_high)
+		nonzero_params |= ETHTOOL_COALESCE_RX_MAX_FRAMES_HIGH;
+	if (coalesce->tx_coalesce_usecs_high)
+		nonzero_params |= ETHTOOL_COALESCE_TX_USECS_HIGH;
+	if (coalesce->tx_max_coalesced_frames_high)
+		nonzero_params |= ETHTOOL_COALESCE_TX_MAX_FRAMES_HIGH;
+	if (coalesce->rate_sample_interval)
+		nonzero_params |= ETHTOOL_COALESCE_RATE_SAMPLE_INTERVAL;
+
+	return (supported_params & nonzero_params) == nonzero_params;
+}
+
 static noinline_for_stack int ethtool_set_coalesce(struct net_device *dev,
 						   void __user *useraddr)
 {
@@ -1555,6 +1613,9 @@ static noinline_for_stack int ethtool_set_coalesce(struct net_device *dev,
 	if (copy_from_user(&coalesce, useraddr, sizeof(coalesce)))
 		return -EFAULT;
 
+	if (!ethtool_set_coalesce_supported(dev, &coalesce))
+		return -EOPNOTSUPP;
+
 	return dev->ethtool_ops->set_coalesce(dev, &coalesce);
 }
 
@@ -2336,6 +2397,11 @@ ethtool_set_per_queue_coalesce(struct net_device *dev,
 			goto roll_back;
 		}
 
+		if (!ethtool_set_coalesce_supported(dev, &coalesce)) {
+			ret = -EOPNOTSUPP;
+			goto roll_back;
+		}
+
 		ret = dev->ethtool_ops->set_per_queue_coalesce(dev, bit, &coalesce);
 		if (ret != 0)
 			goto roll_back;