Merge branch 'ethtool-allow-nesting-of-begin-and-complete-callbacks'

Michal Kubecek says:

====================
ethtool: allow nesting of begin() and complete() callbacks

The ethtool ioctl interface used to guarantee that ethtool_ops callbacks
were always called in a block between calls to ->begin() and ->complete()
(if these are defined) and that this whole block was executed with RTNL
lock held:

	rtnl_lock();
	ops->begin();
	/* other ethtool_ops calls */
	ops->complete();
	rtnl_unlock();

This prevented any nesting or crossing of the begin-complete blocks.
However, this is no longer guaranteed even for ioctl interface as at least
ethtool_phys_id() releases RTNL lock while waiting for a timer. With the
introduction of netlink ethtool interface, the begin-complete pairs are
naturally nested e.g. when a request triggers a netlink notification.

Fortunately, only minority of networking drivers implements begin() and
complete() callbacks and most of those that do, fall into three groups:

  - wrappers for pm_runtime_get_sync() and pm_runtime_put()
  - wrappers for clk_prepare_enable() and clk_disable_unprepare()
  - begin() checks netif_running() (fails if false), no complete()

First two have their own refcounting, third is safe w.r.t. nesting of the
blocks.

Only three in-tree networking drivers need an update to deal with nesting
of begin() and complete() calls: via-velocity and epic100 perform resume
and suspend on their own and wil6210 completely serializes the calls using
its own mutex (which would lead to a deadlock if a request request
triggered a netlink notification). The series addresses these problems.

changes between v1 and v2:
  - fix inverted condition in epic100 ethtool_begin() (thanks to Andrew
    Lunn)
====================

Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2020-01-06 13:54:55 -08:00
commit 50d31037e4
4 changed files with 32 additions and 33 deletions
drivers/net
ethernet
wireless/ath/wil6210

View File

@ -280,6 +280,7 @@ struct epic_private {
signed char phys[4]; /* MII device addresses. */
u16 advertising; /* NWay media advertisement */
int mii_phy_cnt;
u32 ethtool_ops_nesting;
struct mii_if_info mii;
unsigned int tx_full:1; /* The Tx queue is full. */
unsigned int default_port:4; /* Last dev->if_port value. */
@ -1435,8 +1436,10 @@ static int ethtool_begin(struct net_device *dev)
struct epic_private *ep = netdev_priv(dev);
void __iomem *ioaddr = ep->ioaddr;
if (ep->ethtool_ops_nesting == U32_MAX)
return -EBUSY;
/* power-up, if interface is down */
if (!netif_running(dev)) {
if (!ep->ethtool_ops_nesting++ && !netif_running(dev)) {
ew32(GENCTL, 0x0200);
ew32(NVCTL, (er32(NVCTL) & ~0x003c) | 0x4800);
}
@ -1449,7 +1452,7 @@ static void ethtool_complete(struct net_device *dev)
void __iomem *ioaddr = ep->ioaddr;
/* power-down, if interface is down */
if (!netif_running(dev)) {
if (!--ep->ethtool_ops_nesting && !netif_running(dev)) {
ew32(GENCTL, 0x0008);
ew32(NVCTL, (er32(NVCTL) & ~0x483c) | 0x0000);
}

View File

@ -3257,12 +3257,16 @@ static struct platform_driver velocity_platform_driver = {
* @dev: network device
*
* Called before an ethtool operation. We need to make sure the
* chip is out of D3 state before we poke at it.
* chip is out of D3 state before we poke at it. In case of ethtool
* ops nesting, only wake the device up in the outermost block.
*/
static int velocity_ethtool_up(struct net_device *dev)
{
struct velocity_info *vptr = netdev_priv(dev);
if (!netif_running(dev))
if (vptr->ethtool_ops_nesting == U32_MAX)
return -EBUSY;
if (!vptr->ethtool_ops_nesting++ && !netif_running(dev))
velocity_set_power_state(vptr, PCI_D0);
return 0;
}
@ -3272,12 +3276,14 @@ static int velocity_ethtool_up(struct net_device *dev)
* @dev: network device
*
* Called after an ethtool operation. Restore the chip back to D3
* state if it isn't running.
* state if it isn't running. In case of ethtool ops nesting, only
* put the device to sleep in the outermost block.
*/
static void velocity_ethtool_down(struct net_device *dev)
{
struct velocity_info *vptr = netdev_priv(dev);
if (!netif_running(dev))
if (!--vptr->ethtool_ops_nesting && !netif_running(dev))
velocity_set_power_state(vptr, PCI_D3hot);
}

View File

@ -1483,6 +1483,7 @@ struct velocity_info {
struct velocity_context context;
u32 ticks;
u32 ethtool_ops_nesting;
u8 rev_id;

View File

@ -11,26 +11,6 @@
#include "wil6210.h"
static int wil_ethtoolops_begin(struct net_device *ndev)
{
struct wil6210_priv *wil = ndev_to_wil(ndev);
mutex_lock(&wil->mutex);
wil_dbg_misc(wil, "ethtoolops_begin\n");
return 0;
}
static void wil_ethtoolops_complete(struct net_device *ndev)
{
struct wil6210_priv *wil = ndev_to_wil(ndev);
wil_dbg_misc(wil, "ethtoolops_complete\n");
mutex_unlock(&wil->mutex);
}
static int wil_ethtoolops_get_coalesce(struct net_device *ndev,
struct ethtool_coalesce *cp)
{
@ -39,11 +19,12 @@ static int wil_ethtoolops_get_coalesce(struct net_device *ndev,
u32 rx_itr_en, rx_itr_val = 0;
int ret;
mutex_lock(&wil->mutex);
wil_dbg_misc(wil, "ethtoolops_get_coalesce\n");
ret = wil_pm_runtime_get(wil);
if (ret < 0)
return ret;
goto out;
tx_itr_en = wil_r(wil, RGF_DMA_ITR_TX_CNT_CTL);
if (tx_itr_en & BIT_DMA_ITR_TX_CNT_CTL_EN)
@ -57,7 +38,11 @@ static int wil_ethtoolops_get_coalesce(struct net_device *ndev,
cp->tx_coalesce_usecs = tx_itr_val;
cp->rx_coalesce_usecs = rx_itr_val;
return 0;
ret = 0;
out:
mutex_unlock(&wil->mutex);
return ret;
}
static int wil_ethtoolops_set_coalesce(struct net_device *ndev,
@ -67,12 +52,14 @@ static int wil_ethtoolops_set_coalesce(struct net_device *ndev,
struct wireless_dev *wdev = ndev->ieee80211_ptr;
int ret;
mutex_lock(&wil->mutex);
wil_dbg_misc(wil, "ethtoolops_set_coalesce: rx %d usec, tx %d usec\n",
cp->rx_coalesce_usecs, cp->tx_coalesce_usecs);
if (wdev->iftype == NL80211_IFTYPE_MONITOR) {
wil_dbg_misc(wil, "No IRQ coalescing in monitor mode\n");
return -EINVAL;
ret = -EINVAL;
goto out;
}
/* only @rx_coalesce_usecs and @tx_coalesce_usecs supported,
@ -88,24 +75,26 @@ static int wil_ethtoolops_set_coalesce(struct net_device *ndev,
ret = wil_pm_runtime_get(wil);
if (ret < 0)
return ret;
goto out;
wil->txrx_ops.configure_interrupt_moderation(wil);
wil_pm_runtime_put(wil);
ret = 0;
return 0;
out:
mutex_unlock(&wil->mutex);
return ret;
out_bad:
wil_dbg_misc(wil, "Unsupported coalescing params. Raw command:\n");
print_hex_dump_debug("DBG[MISC] coal ", DUMP_PREFIX_OFFSET, 16, 4,
cp, sizeof(*cp), false);
mutex_unlock(&wil->mutex);
return -EINVAL;
}
static const struct ethtool_ops wil_ethtool_ops = {
.begin = wil_ethtoolops_begin,
.complete = wil_ethtoolops_complete,
.get_drvinfo = cfg80211_get_drvinfo,
.get_coalesce = wil_ethtoolops_get_coalesce,
.set_coalesce = wil_ethtoolops_set_coalesce,