Revision 6e474083f3daf3a3546737f5d7d502ad12eb257c authored by Wei Xu on 01 December 2017, 10:10:36 UTC, committed by David S. Miller on 03 December 2017, 02:31:03 UTC
Matthew found a roughly 40% tcp throughput regression with commit c67df11f(vhost_net: try batch dequing from skb array) as discussed in the following thread: https://www.mail-archive.com/netdev@vger.kernel.org/msg187936.html Eventually we figured out that it was a skb leak in handle_rx() when sending packets to the VM. This usually happens when a guest can not drain out vq as fast as vhost fills in, afterwards it sets off the traffic jam and leaks skb(s) which occurs as no headcount to send on the vq from vhost side. This can be avoided by making sure we have got enough headcount before actually consuming a skb from the batched rx array while transmitting, which is simply done by moving checking the zero headcount a bit ahead. Signed-off-by: Wei Xu <wexu@redhat.com> Reported-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent fa935ca
i2c-powermac.c
/*
i2c Support for Apple SMU Controller
Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
<benh@kernel.crashing.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/of_irq.h>
#include <asm/prom.h>
#include <asm/pmac_low_i2c.h>
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
MODULE_LICENSE("GPL");
/*
* SMBUS-type transfer entrypoint
*/
static s32 i2c_powermac_smbus_xfer( struct i2c_adapter* adap,
u16 addr,
unsigned short flags,
char read_write,
u8 command,
int size,
union i2c_smbus_data* data)
{
struct pmac_i2c_bus *bus = i2c_get_adapdata(adap);
int rc = 0;
int read = (read_write == I2C_SMBUS_READ);
int addrdir = (addr << 1) | read;
int mode, subsize, len;
u32 subaddr;
u8 *buf;
u8 local[2];
if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) {
mode = pmac_i2c_mode_std;
subsize = 0;
subaddr = 0;
} else {
mode = read ? pmac_i2c_mode_combined : pmac_i2c_mode_stdsub;
subsize = 1;
subaddr = command;
}
switch (size) {
case I2C_SMBUS_QUICK:
buf = NULL;
len = 0;
break;
case I2C_SMBUS_BYTE:
case I2C_SMBUS_BYTE_DATA:
buf = &data->byte;
len = 1;
break;
case I2C_SMBUS_WORD_DATA:
if (!read) {
local[0] = data->word & 0xff;
local[1] = (data->word >> 8) & 0xff;
}
buf = local;
len = 2;
break;
/* Note that these are broken vs. the expected smbus API where
* on reads, the length is actually returned from the function,
* but I think the current API makes no sense and I don't want
* any driver that I haven't verified for correctness to go
* anywhere near a pmac i2c bus anyway ...
*
* I'm also not completely sure what kind of phases to do between
* the actual command and the data (what I am _supposed_ to do that
* is). For now, I assume writes are a single stream and reads have
* a repeat start/addr phase (but not stop in between)
*/
case I2C_SMBUS_BLOCK_DATA:
buf = data->block;
len = data->block[0] + 1;
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
buf = &data->block[1];
len = data->block[0];
break;
default:
return -EINVAL;
}
rc = pmac_i2c_open(bus, 0);
if (rc) {
dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
return rc;
}
rc = pmac_i2c_setmode(bus, mode);
if (rc) {
dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
mode, rc);
goto bail;
}
rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
if (rc) {
if (rc == -ENXIO)
dev_dbg(&adap->dev,
"I2C transfer at 0x%02x failed, size %d, "
"err %d\n", addrdir >> 1, size, rc);
else
dev_err(&adap->dev,
"I2C transfer at 0x%02x failed, size %d, "
"err %d\n", addrdir >> 1, size, rc);
goto bail;
}
if (size == I2C_SMBUS_WORD_DATA && read) {
data->word = ((u16)local[1]) << 8;
data->word |= local[0];
}
bail:
pmac_i2c_close(bus);
return rc;
}
/*
* Generic i2c master transfer entrypoint. This driver only support single
* messages (for "lame i2c" transfers). Anything else should use the smbus
* entry point
*/
static int i2c_powermac_master_xfer( struct i2c_adapter *adap,
struct i2c_msg *msgs,
int num)
{
struct pmac_i2c_bus *bus = i2c_get_adapdata(adap);
int rc = 0;
int addrdir;
if (msgs->flags & I2C_M_TEN)
return -EINVAL;
addrdir = i2c_8bit_addr_from_msg(msgs);
rc = pmac_i2c_open(bus, 0);
if (rc) {
dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
return rc;
}
rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
if (rc) {
dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
pmac_i2c_mode_std, rc);
goto bail;
}
rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
if (rc < 0) {
if (rc == -ENXIO)
dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
addrdir & 1 ? "read from" : "write to",
addrdir >> 1, rc);
else
dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
addrdir & 1 ? "read from" : "write to",
addrdir >> 1, rc);
}
bail:
pmac_i2c_close(bus);
return rc < 0 ? rc : 1;
}
static u32 i2c_powermac_func(struct i2c_adapter * adapter)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
}
/* For now, we only handle smbus */
static const struct i2c_algorithm i2c_powermac_algorithm = {
.smbus_xfer = i2c_powermac_smbus_xfer,
.master_xfer = i2c_powermac_master_xfer,
.functionality = i2c_powermac_func,
};
static const struct i2c_adapter_quirks i2c_powermac_quirks = {
.max_num_msgs = 1,
};
static int i2c_powermac_remove(struct platform_device *dev)
{
struct i2c_adapter *adapter = platform_get_drvdata(dev);
i2c_del_adapter(adapter);
memset(adapter, 0, sizeof(*adapter));
return 0;
}
static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
struct pmac_i2c_bus *bus,
struct device_node *node)
{
const __be32 *prop;
int len;
/* First check for valid "reg" */
prop = of_get_property(node, "reg", &len);
if (prop && (len >= sizeof(int)))
return (be32_to_cpup(prop) & 0xff) >> 1;
/* Then check old-style "i2c-address" */
prop = of_get_property(node, "i2c-address", &len);
if (prop && (len >= sizeof(int)))
return (be32_to_cpup(prop) & 0xff) >> 1;
/* Now handle some devices with missing "reg" properties */
if (!strcmp(node->name, "cereal"))
return 0x60;
else if (!strcmp(node->name, "deq"))
return 0x34;
dev_warn(&adap->dev, "No i2c address for %pOF\n", node);
return 0xffffffff;
}
static void i2c_powermac_create_one(struct i2c_adapter *adap,
const char *type,
u32 addr)
{
struct i2c_board_info info = {};
struct i2c_client *newdev;
strncpy(info.type, type, sizeof(info.type));
info.addr = addr;
newdev = i2c_new_device(adap, &info);
if (!newdev)
dev_err(&adap->dev,
"i2c-powermac: Failure to register missing %s\n",
type);
}
static void i2c_powermac_add_missing(struct i2c_adapter *adap,
struct pmac_i2c_bus *bus,
bool found_onyx)
{
struct device_node *busnode = pmac_i2c_get_bus_node(bus);
int rc;
/* Check for the onyx audio codec */
#define ONYX_REG_CONTROL 67
if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
union i2c_smbus_data data;
rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
&data);
if (rc >= 0)
i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
&data);
if (rc >= 0)
i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
}
}
static bool i2c_powermac_get_type(struct i2c_adapter *adap,
struct device_node *node,
u32 addr, char *type, int type_size)
{
char tmp[16];
/* Note: we to _NOT_ want the standard
* i2c drivers to match with any of our powermac stuff
* unless they have been specifically modified to handle
* it on a case by case basis. For example, for thermal
* control, things like lm75 etc... shall match with their
* corresponding windfarm drivers, _NOT_ the generic ones,
* so we force a prefix of AAPL, onto the modalias to
* make that happen
*/
/* First try proper modalias */
if (of_modalias_node(node, tmp, sizeof(tmp)) >= 0) {
snprintf(type, type_size, "MAC,%s", tmp);
return true;
}
/* Now look for known workarounds */
if (!strcmp(node->name, "deq")) {
/* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
if (addr == 0x34) {
snprintf(type, type_size, "MAC,tas3001");
return true;
} else if (addr == 0x35) {
snprintf(type, type_size, "MAC,tas3004");
return true;
}
}
dev_err(&adap->dev, "i2c-powermac: modalias failure on %pOF\n", node);
return false;
}
static void i2c_powermac_register_devices(struct i2c_adapter *adap,
struct pmac_i2c_bus *bus)
{
struct i2c_client *newdev;
struct device_node *node;
bool found_onyx = 0;
/*
* In some cases we end up with the via-pmu node itself, in this
* case we skip this function completely as the device-tree will
* not contain anything useful.
*/
if (!strcmp(adap->dev.of_node->name, "via-pmu"))
return;
for_each_child_of_node(adap->dev.of_node, node) {
struct i2c_board_info info = {};
u32 addr;
/* Get address & channel */
addr = i2c_powermac_get_addr(adap, bus, node);
if (addr == 0xffffffff)
continue;
/* Multibus setup, check channel */
if (!pmac_i2c_match_adapter(node, adap))
continue;
dev_dbg(&adap->dev, "i2c-powermac: register %pOF\n", node);
/*
* Keep track of some device existence to handle
* workarounds later.
*/
if (of_device_is_compatible(node, "pcm3052"))
found_onyx = true;
/* Make up a modalias */
if (!i2c_powermac_get_type(adap, node, addr,
info.type, sizeof(info.type))) {
continue;
}
/* Fill out the rest of the info structure */
info.addr = addr;
info.irq = irq_of_parse_and_map(node, 0);
info.of_node = of_node_get(node);
newdev = i2c_new_device(adap, &info);
if (!newdev) {
dev_err(&adap->dev, "i2c-powermac: Failure to register"
" %pOF\n", node);
of_node_put(node);
/* We do not dispose of the interrupt mapping on
* purpose. It's not necessary (interrupt cannot be
* re-used) and somebody else might have grabbed it
* via direct DT lookup so let's not bother
*/
continue;
}
}
/* Additional workarounds */
i2c_powermac_add_missing(adap, bus, found_onyx);
}
static int i2c_powermac_probe(struct platform_device *dev)
{
struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
struct device_node *parent = NULL;
struct i2c_adapter *adapter;
const char *basename;
int rc;
if (bus == NULL)
return -EINVAL;
adapter = pmac_i2c_get_adapter(bus);
/* Ok, now we need to make up a name for the interface that will
* match what we used to do in the past, that is basically the
* controller's parent device node for keywest. PMU didn't have a
* naming convention and SMU has a different one
*/
switch(pmac_i2c_get_type(bus)) {
case pmac_i2c_bus_keywest:
parent = of_get_parent(pmac_i2c_get_controller(bus));
if (parent == NULL)
return -EINVAL;
basename = parent->name;
break;
case pmac_i2c_bus_pmu:
basename = "pmu";
break;
case pmac_i2c_bus_smu:
/* This is not what we used to do but I'm fixing drivers at
* the same time as this change
*/
basename = "smu";
break;
default:
return -EINVAL;
}
snprintf(adapter->name, sizeof(adapter->name), "%s %d", basename,
pmac_i2c_get_channel(bus));
of_node_put(parent);
platform_set_drvdata(dev, adapter);
adapter->algo = &i2c_powermac_algorithm;
adapter->quirks = &i2c_powermac_quirks;
i2c_set_adapdata(adapter, bus);
adapter->dev.parent = &dev->dev;
/* Clear of_node to skip automatic registration of i2c child nodes */
adapter->dev.of_node = NULL;
rc = i2c_add_adapter(adapter);
if (rc) {
printk(KERN_ERR "i2c-powermac: Adapter %s registration "
"failed\n", adapter->name);
memset(adapter, 0, sizeof(*adapter));
return rc;
}
printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
/* Use custom child registration due to Apple device-tree funkyness */
adapter->dev.of_node = dev->dev.of_node;
i2c_powermac_register_devices(adapter, bus);
return 0;
}
static struct platform_driver i2c_powermac_driver = {
.probe = i2c_powermac_probe,
.remove = i2c_powermac_remove,
.driver = {
.name = "i2c-powermac",
.bus = &platform_bus_type,
},
};
module_platform_driver(i2c_powermac_driver);
MODULE_ALIAS("platform:i2c-powermac");
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