OpenCloudOS-Kernel/drivers/net/ethernet/cisco/enic/enic_api.c

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drivers/net/ethernet: clean up mis-targeted comments As part of the W=1 cleanups for ethernet, a million [*] driver comments had to be cleaned up to get the W=1 compilation to succeed. This change finally makes the drivers/net/ethernet tree compile with W=1 set on the command line. NOTE: The kernel uses kdoc style (see Documentation/process/kernel-doc.rst) when documenting code, not doxygen or other styles. After this patch the x86_64 build has no warnings from W=1, however scripts/kernel-doc says there are 1545 more warnings in source files, that I need to develop a script to fix in a followup patch. The errors fixed here are all kdoc of a few classes, with a few outliers: In file included from drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c:10: drivers/net/ethernet/qlogic/netxen/netxen_nic.h:1193:18: warning: ‘FW_DUMP_LEVELS’ defined but not used [-Wunused-const-variable=] 1193 | static const u32 FW_DUMP_LEVELS[] = { 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff }; | ^~~~~~~~~~~~~~ ... repeats 4 times... drivers/net/ethernet/sun/cassini.c:2084:24: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body] 2084 | RX_USED_ADD(page, i); drivers/net/ethernet/natsemi/ns83820.c: In function ‘phy_intr’: drivers/net/ethernet/natsemi/ns83820.c:603:6: warning: variable ‘tbisr’ set but not used [-Wunused-but-set-variable] 603 | u32 tbisr, tanar, tanlpar; | ^~~~~ drivers/net/ethernet/natsemi/ns83820.c: In function ‘ns83820_get_link_ksettings’: drivers/net/ethernet/natsemi/ns83820.c:1207:11: warning: variable ‘tanar’ set but not used [-Wunused-but-set-variable] 1207 | u32 cfg, tanar, tbicr; | ^~~~~ drivers/net/ethernet/packetengines/yellowfin.c:1063:18: warning: variable ‘yf_size’ set but not used [-Wunused-but-set-variable] 1063 | int data_size, yf_size; | ^~~~~~~ Normal kdoc fixes: warning: Function parameter or member 'x' not described in 'y' warning: Excess function parameter 'x' description in 'y' warning: Cannot understand <string> on line <NNN> - I thought it was a doc line [*] - ok it wasn't quite a million, but it felt like it. Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-26 06:24:45 +08:00
/*
* Copyright 2013 Cisco Systems, Inc. All rights reserved.
*
* This program is free software; you may redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include "vnic_dev.h"
#include "vnic_devcmd.h"
#include "enic_res.h"
#include "enic.h"
#include "enic_api.h"
int enic_api_devcmd_proxy_by_index(struct net_device *netdev, int vf,
enum vnic_devcmd_cmd cmd, u64 *a0, u64 *a1, int wait)
{
int err;
struct enic *enic = netdev_priv(netdev);
struct vnic_dev *vdev = enic->vdev;
spin_lock(&enic->enic_api_lock);
net: enic: Cure the enic api locking trainwreck enic_dev_wait() has a BUG_ON(in_interrupt()). Chasing the callers of enic_dev_wait() revealed the gems of enic_reset() and enic_tx_hang_reset() which are both invoked through work queues in order to be able to call rtnl_lock(). So far so good. After locking rtnl both functions acquire enic::enic_api_lock which serializes against the (ab)use from infiniband. This is where the trainwreck starts. enic::enic_api_lock is a spin_lock() which implicitly disables preemption, but both functions invoke a ton of functions under that lock which can sleep. The BUG_ON(in_interrupt()) does not trigger in that case because it can't detect the preempt disabled condition. This clearly has never been tested with any of the mandatory debug options for 7+ years, which would have caught that for sure. Cure it by adding a enic_api_busy member to struct enic, which is modified and evaluated with enic::enic_api_lock held. If enic_api_devcmd_proxy_by_index() observes enic::enic_api_busy as true, it drops enic::enic_api_lock and busy waits for enic::enic_api_busy to become false. It would be smarter to wait for a completion of that busy period, but enic_api_devcmd_proxy_by_index() is called with other spin locks held which obviously can't sleep. Remove the BUG_ON(in_interrupt()) check as well because it's incomplete and with proper debugging enabled the problem would have been caught from the debug checks in schedule_timeout(). Fixes: 0b038566c0ea ("drivers/net: enic: Add an interface for USNIC to interact with firmware") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 04:25:10 +08:00
while (enic->enic_api_busy) {
spin_unlock(&enic->enic_api_lock);
cpu_relax();
spin_lock(&enic->enic_api_lock);
}
spin_lock_bh(&enic->devcmd_lock);
vnic_dev_cmd_proxy_by_index_start(vdev, vf);
err = vnic_dev_cmd(vdev, cmd, a0, a1, wait);
vnic_dev_cmd_proxy_end(vdev);
spin_unlock_bh(&enic->devcmd_lock);
spin_unlock(&enic->enic_api_lock);
return err;
}
EXPORT_SYMBOL(enic_api_devcmd_proxy_by_index);