Revision 9c29bcd189f4ab1644b7125713602532d0aefdb7 authored by Eric Dumazet on 21 September 2018, 22:27:48 UTC, committed by David S. Miller on 24 September 2018, 04:55:25 UTC
As diagnosed by Song Liu, ndo_poll_controller() can be very dangerous on loaded hosts, since the cpu calling ndo_poll_controller() might steal all NAPI contexts (for all RX/TX queues of the NIC). This capture can last for unlimited amount of time, since one cpu is generally not able to drain all the queues under load. mlx5 uses NAPI for TX completions, so we better let core networking stack call the napi->poll() to avoid the capture. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent a24b66c
iomap_copy.c
/*
* Copyright 2006 PathScale, Inc. All Rights Reserved.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/export.h>
#include <linux/io.h>
/**
* __iowrite32_copy - copy data to MMIO space, in 32-bit units
* @to: destination, in MMIO space (must be 32-bit aligned)
* @from: source (must be 32-bit aligned)
* @count: number of 32-bit quantities to copy
*
* Copy data from kernel space to MMIO space, in units of 32 bits at a
* time. Order of access is not guaranteed, nor is a memory barrier
* performed afterwards.
*/
void __attribute__((weak)) __iowrite32_copy(void __iomem *to,
const void *from,
size_t count)
{
u32 __iomem *dst = to;
const u32 *src = from;
const u32 *end = src + count;
while (src < end)
__raw_writel(*src++, dst++);
}
EXPORT_SYMBOL_GPL(__iowrite32_copy);
/**
* __ioread32_copy - copy data from MMIO space, in 32-bit units
* @to: destination (must be 32-bit aligned)
* @from: source, in MMIO space (must be 32-bit aligned)
* @count: number of 32-bit quantities to copy
*
* Copy data from MMIO space to kernel space, in units of 32 bits at a
* time. Order of access is not guaranteed, nor is a memory barrier
* performed afterwards.
*/
void __ioread32_copy(void *to, const void __iomem *from, size_t count)
{
u32 *dst = to;
const u32 __iomem *src = from;
const u32 __iomem *end = src + count;
while (src < end)
*dst++ = __raw_readl(src++);
}
EXPORT_SYMBOL_GPL(__ioread32_copy);
/**
* __iowrite64_copy - copy data to MMIO space, in 64-bit or 32-bit units
* @to: destination, in MMIO space (must be 64-bit aligned)
* @from: source (must be 64-bit aligned)
* @count: number of 64-bit quantities to copy
*
* Copy data from kernel space to MMIO space, in units of 32 or 64 bits at a
* time. Order of access is not guaranteed, nor is a memory barrier
* performed afterwards.
*/
void __attribute__((weak)) __iowrite64_copy(void __iomem *to,
const void *from,
size_t count)
{
#ifdef CONFIG_64BIT
u64 __iomem *dst = to;
const u64 *src = from;
const u64 *end = src + count;
while (src < end)
__raw_writeq(*src++, dst++);
#else
__iowrite32_copy(to, from, count * 2);
#endif
}
EXPORT_SYMBOL_GPL(__iowrite64_copy);
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