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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 
mlx5: remove ndo_poll_controller
 
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
Raw File
crc4.c 
/*
 * crc4.c - simple crc-4 calculations.
 *
 * This source code is licensed under the GNU General Public License, Version
 * 2. See the file COPYING for more details.
 */

#include <linux/crc4.h>
#include <linux/module.h>

static const uint8_t crc4_tab[] = {
	0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2,
	0x1, 0x6, 0xf, 0x8, 0xa, 0xd, 0x4, 0x3,
};

/**
 * crc4 - calculate the 4-bit crc of a value.
 * @c:    starting crc4
 * @x:    value to checksum
 * @bits: number of bits in @x to checksum
 *
 * Returns the crc4 value of @x, using polynomial 0b10111.
 *
 * The @x value is treated as left-aligned, and bits above @bits are ignored
 * in the crc calculations.
 */
uint8_t crc4(uint8_t c, uint64_t x, int bits)
{
	int i;

	/* mask off anything above the top bit */
	x &= (1ull << bits) - 1;

	/* Align to 4-bits */
	bits = (bits + 3) & ~0x3;

	/* Calculate crc4 over four-bit nibbles, starting at the MSbit */
	for (i = bits - 4; i >= 0; i -= 4)
		c = crc4_tab[c ^ ((x >> i) & 0xf)];

	return c;
}
EXPORT_SYMBOL_GPL(crc4);

MODULE_DESCRIPTION("CRC4 calculations");
MODULE_LICENSE("GPL");
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