Re: [patch] pm_qos update fixing mmotm 2010-05-11 -dies in pm_qos_update_request()
From: Rafael J. Wysocki
Date: Sat May 15 2010 - 15:38:14 EST
On Saturday 15 May 2010, mgross wrote:
> I apologize for the goofy email address.
>
> The following is a fix for the crash reported by Valdis.
>
> The problem was that the original pm_qos silently fails when a request
> update is passed to a parameter that has not been added to the list
> yet. It seems that the e1000e is doing this. This update restores this
> behavior.
>
> I need to think about how to better handle such abuse, but for now this
> restores the original behavior.
Can you please post a signed-off incremental patch against
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6.git for-llinus
that contains your original PM QOS update?
Thanks,
Rafael
> Signed-off-by: markgross <markgross@xxxxxxxxxxx>
> --mgross
>
>
> From 66700dc26ab7582bc7351541ba2e6241cc4b4144 Mon Sep 17 00:00:00 2001
> From: mgross <mgross@mgross-desktop.(none)>
> Date: Fri, 14 May 2010 19:05:44 -0700
> Subject: [PATCH] PM QOS update
> This patch changes the string based list management to a handle base
> implementation to help with the hot path use of pm-qos, it also renames
> much of the API to use "request" as opposed to "requirement" that was
> used in the initial implementation. I did this because request more
> accurately represents what it actually does.
>
> Also, I added a string based ABI for users wanting to use a string
> interface. So if the user writes 0xDDDDDDDD formatted hex it will be
> accepted by the interface. (someone asked me for it and I don't think
> it hurts anything.)
>
> This patch updates some documentation input I got from Randy.
>
> This version handles a use case where pm_qos update requests need to
> silently not fail if the update is being sent to a handle that is null.
> This is what happened in the initial version of pm-qos if you used a
> string that wasn't in the list.
>
> Signed-off-by: markgross <mgross@xxxxxxxxxxxxxxx>
> ---
> Documentation/power/pm_qos_interface.txt | 48 ++++---
> drivers/acpi/processor_idle.c | 2 +-
> drivers/cpuidle/governors/ladder.c | 2 +-
> drivers/cpuidle/governors/menu.c | 2 +-
> drivers/net/e1000e/netdev.c | 22 ++--
> drivers/net/igbvf/netdev.c | 6 +-
> drivers/net/wireless/ipw2x00/ipw2100.c | 11 +-
> include/linux/netdevice.h | 4 +
> include/linux/pm_qos_params.h | 14 +-
> include/sound/pcm.h | 3 +-
> kernel/pm_qos_params.c | 217 +++++++++++++++---------------
> net/mac80211/mlme.c | 2 +-
> sound/core/pcm.c | 3 -
> sound/core/pcm_native.c | 14 +-
> 14 files changed, 179 insertions(+), 171 deletions(-)
>
> diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt
> index c40866e..bfed898 100644
> --- a/Documentation/power/pm_qos_interface.txt
> +++ b/Documentation/power/pm_qos_interface.txt
> @@ -18,44 +18,46 @@ and pm_qos_params.h. This is done because having the available parameters
> being runtime configurable or changeable from a driver was seen as too easy to
> abuse.
>
> -For each parameter a list of performance requirements is maintained along with
> +For each parameter a list of performance requests is maintained along with
> an aggregated target value. The aggregated target value is updated with
> -changes to the requirement list or elements of the list. Typically the
> -aggregated target value is simply the max or min of the requirement values held
> +changes to the request list or elements of the list. Typically the
> +aggregated target value is simply the max or min of the request values held
> in the parameter list elements.
>
> From kernel mode the use of this interface is simple:
> -pm_qos_add_requirement(param_id, name, target_value):
> -Will insert a named element in the list for that identified PM_QOS parameter
> -with the target value. Upon change to this list the new target is recomputed
> -and any registered notifiers are called only if the target value is now
> -different.
>
> -pm_qos_update_requirement(param_id, name, new_target_value):
> -Will search the list identified by the param_id for the named list element and
> -then update its target value, calling the notification tree if the aggregated
> -target is changed. with that name is already registered.
> +handle = pm_qos_add_request(param_class, target_value):
> +Will insert an element into the list for that identified PM_QOS class with the
> +target value. Upon change to this list the new target is recomputed and any
> +registered notifiers are called only if the target value is now different.
> +Clients of pm_qos need to save the returned handle.
>
> -pm_qos_remove_requirement(param_id, name):
> -Will search the identified list for the named element and remove it, after
> -removal it will update the aggregate target and call the notification tree if
> -the target was changed as a result of removing the named requirement.
> +void pm_qos_update_request(handle, new_target_value):
> +Will update the list element pointed to by the handle with the new target value
> +and recompute the new aggregated target, calling the notification tree if the
> +target is changed.
> +
> +void pm_qos_remove_request(handle):
> +Will remove the element. After removal it will update the aggregate target and
> +call the notification tree if the target was changed as a result of removing
> +the request.
>
>
> From user mode:
> -Only processes can register a pm_qos requirement. To provide for automatic
> -cleanup for process the interface requires the process to register its
> -parameter requirements in the following way:
> +Only processes can register a pm_qos request. To provide for automatic
> +cleanup of a process, the interface requires the process to register its
> +parameter requests in the following way:
>
> To register the default pm_qos target for the specific parameter, the process
> must open one of /dev/[cpu_dma_latency, network_latency, network_throughput]
>
> As long as the device node is held open that process has a registered
> -requirement on the parameter. The name of the requirement is "process_<PID>"
> -derived from the current->pid from within the open system call.
> +request on the parameter.
>
> -To change the requested target value the process needs to write a s32 value to
> -the open device node. This translates to a pm_qos_update_requirement call.
> +To change the requested target value the process needs to write an s32 value to
> +the open device node. Alternatively the user mode program could write a hex
> +string for the value using 10 char long format e.g. "0x12345678". This
> +translates to a pm_qos_update_request call.
>
> To remove the user mode request for a target value simply close the device
> node.
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 5939e7f..c3817e1 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -698,7 +698,7 @@ static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
> "max_cstate: C%d\n"
> "maximum allowed latency: %d usec\n",
> pr->power.state ? pr->power.state - pr->power.states : 0,
> - max_cstate, pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY));
> + max_cstate, pm_qos_request(PM_QOS_CPU_DMA_LATENCY));
>
> seq_puts(seq, "states:\n");
>
> diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
> index 1c1ceb4..12c9890 100644
> --- a/drivers/cpuidle/governors/ladder.c
> +++ b/drivers/cpuidle/governors/ladder.c
> @@ -67,7 +67,7 @@ static int ladder_select_state(struct cpuidle_device *dev)
> struct ladder_device *ldev = &__get_cpu_var(ladder_devices);
> struct ladder_device_state *last_state;
> int last_residency, last_idx = ldev->last_state_idx;
> - int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
> + int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
>
> /* Special case when user has set very strict latency requirement */
> if (unlikely(latency_req == 0)) {
> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
> index f8e57c6..b81ad9c 100644
> --- a/drivers/cpuidle/governors/menu.c
> +++ b/drivers/cpuidle/governors/menu.c
> @@ -182,7 +182,7 @@ static u64 div_round64(u64 dividend, u32 divisor)
> static int menu_select(struct cpuidle_device *dev)
> {
> struct menu_device *data = &__get_cpu_var(menu_devices);
> - int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
> + int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
> int i;
> int multiplier;
>
> diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
> index dbf8178..d5d55c6 100644
> --- a/drivers/net/e1000e/netdev.c
> +++ b/drivers/net/e1000e/netdev.c
> @@ -2524,12 +2524,12 @@ static void e1000_configure_rx(struct e1000_adapter *adapter)
> * excessive C-state transition latencies result in
> * dropped transactions.
> */
> - pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY,
> - adapter->netdev->name, 55);
> + pm_qos_update_request(
> + adapter->netdev->pm_qos_req, 55);
> } else {
> - pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY,
> - adapter->netdev->name,
> - PM_QOS_DEFAULT_VALUE);
> + pm_qos_update_request(
> + adapter->netdev->pm_qos_req,
> + PM_QOS_DEFAULT_VALUE);
> }
> }
>
> @@ -2824,8 +2824,8 @@ int e1000e_up(struct e1000_adapter *adapter)
>
> /* DMA latency requirement to workaround early-receive/jumbo issue */
> if (adapter->flags & FLAG_HAS_ERT)
> - pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
> - adapter->netdev->name,
> + adapter->netdev->pm_qos_req =
> + pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
> PM_QOS_DEFAULT_VALUE);
>
> /* hardware has been reset, we need to reload some things */
> @@ -2887,9 +2887,11 @@ void e1000e_down(struct e1000_adapter *adapter)
> e1000_clean_tx_ring(adapter);
> e1000_clean_rx_ring(adapter);
>
> - if (adapter->flags & FLAG_HAS_ERT)
> - pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
> - adapter->netdev->name);
> + if (adapter->flags & FLAG_HAS_ERT) {
> + pm_qos_remove_request(
> + adapter->netdev->pm_qos_req);
> + adapter->netdev->pm_qos_req = NULL;
> + }
>
> /*
> * TODO: for power management, we could drop the link and
> diff --git a/drivers/net/igbvf/netdev.c b/drivers/net/igbvf/netdev.c
> index 1b1edad..f16e981 100644
> --- a/drivers/net/igbvf/netdev.c
> +++ b/drivers/net/igbvf/netdev.c
> @@ -48,6 +48,7 @@
> #define DRV_VERSION "1.0.0-k0"
> char igbvf_driver_name[] = "igbvf";
> const char igbvf_driver_version[] = DRV_VERSION;
> +struct pm_qos_request_list *igbvf_driver_pm_qos_req;
> static const char igbvf_driver_string[] =
> "Intel(R) Virtual Function Network Driver";
> static const char igbvf_copyright[] = "Copyright (c) 2009 Intel Corporation.";
> @@ -2899,7 +2900,7 @@ static int __init igbvf_init_module(void)
> printk(KERN_INFO "%s\n", igbvf_copyright);
>
> ret = pci_register_driver(&igbvf_driver);
> - pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY, igbvf_driver_name,
> + igbvf_driver_pm_qos_req = pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
> PM_QOS_DEFAULT_VALUE);
>
> return ret;
> @@ -2915,7 +2916,8 @@ module_init(igbvf_init_module);
> static void __exit igbvf_exit_module(void)
> {
> pci_unregister_driver(&igbvf_driver);
> - pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY, igbvf_driver_name);
> + pm_qos_remove_request(igbvf_driver_pm_qos_req);
> + igbvf_driver_pm_qos_req = NULL;
> }
> module_exit(igbvf_exit_module);
>
> diff --git a/drivers/net/wireless/ipw2x00/ipw2100.c b/drivers/net/wireless/ipw2x00/ipw2100.c
> index 9b72c45..2b05fe5 100644
> --- a/drivers/net/wireless/ipw2x00/ipw2100.c
> +++ b/drivers/net/wireless/ipw2x00/ipw2100.c
> @@ -174,6 +174,8 @@ that only one external action is invoked at a time.
> #define DRV_DESCRIPTION "Intel(R) PRO/Wireless 2100 Network Driver"
> #define DRV_COPYRIGHT "Copyright(c) 2003-2006 Intel Corporation"
>
> +struct pm_qos_request_list *ipw2100_pm_qos_req;
> +
> /* Debugging stuff */
> #ifdef CONFIG_IPW2100_DEBUG
> #define IPW2100_RX_DEBUG /* Reception debugging */
> @@ -1739,7 +1741,7 @@ static int ipw2100_up(struct ipw2100_priv *priv, int deferred)
> /* the ipw2100 hardware really doesn't want power management delays
> * longer than 175usec
> */
> - pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100", 175);
> + pm_qos_update_request(ipw2100_pm_qos_req, 175);
>
> /* If the interrupt is enabled, turn it off... */
> spin_lock_irqsave(&priv->low_lock, flags);
> @@ -1887,8 +1889,7 @@ static void ipw2100_down(struct ipw2100_priv *priv)
> ipw2100_disable_interrupts(priv);
> spin_unlock_irqrestore(&priv->low_lock, flags);
>
> - pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
> - PM_QOS_DEFAULT_VALUE);
> + pm_qos_update_request(ipw2100_pm_qos_req, PM_QOS_DEFAULT_VALUE);
>
> /* We have to signal any supplicant if we are disassociating */
> if (associated)
> @@ -6669,7 +6670,7 @@ static int __init ipw2100_init(void)
> if (ret)
> goto out;
>
> - pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
> + ipw2100_pm_qos_req = pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
> PM_QOS_DEFAULT_VALUE);
> #ifdef CONFIG_IPW2100_DEBUG
> ipw2100_debug_level = debug;
> @@ -6692,7 +6693,7 @@ static void __exit ipw2100_exit(void)
> &driver_attr_debug_level);
> #endif
> pci_unregister_driver(&ipw2100_pci_driver);
> - pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100");
> + pm_qos_remove_request(ipw2100_pm_qos_req);
> }
>
> module_init(ipw2100_init);
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index fa8b476..3857517 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -31,6 +31,7 @@
> #include <linux/if_link.h>
>
> #ifdef __KERNEL__
> +#include <linux/pm_qos_params.h>
> #include <linux/timer.h>
> #include <linux/delay.h>
> #include <linux/mm.h>
> @@ -711,6 +712,9 @@ struct net_device {
> * the interface.
> */
> char name[IFNAMSIZ];
> +
> + struct pm_qos_request_list *pm_qos_req;
> +
> /* device name hash chain */
> struct hlist_node name_hlist;
> /* snmp alias */
> diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
> index d74f75e..8ba440e 100644
> --- a/include/linux/pm_qos_params.h
> +++ b/include/linux/pm_qos_params.h
> @@ -14,12 +14,14 @@
> #define PM_QOS_NUM_CLASSES 4
> #define PM_QOS_DEFAULT_VALUE -1
>
> -int pm_qos_add_requirement(int qos, char *name, s32 value);
> -int pm_qos_update_requirement(int qos, char *name, s32 new_value);
> -void pm_qos_remove_requirement(int qos, char *name);
> +struct pm_qos_request_list;
>
> -int pm_qos_requirement(int qos);
> +struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value);
> +void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
> + s32 new_value);
> +void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req);
>
> -int pm_qos_add_notifier(int qos, struct notifier_block *notifier);
> -int pm_qos_remove_notifier(int qos, struct notifier_block *notifier);
> +int pm_qos_request(int pm_qos_class);
> +int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
> +int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
>
> diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> index 8b611a5..dd76cde 100644
> --- a/include/sound/pcm.h
> +++ b/include/sound/pcm.h
> @@ -29,6 +29,7 @@
> #include <linux/poll.h>
> #include <linux/mm.h>
> #include <linux/bitops.h>
> +#include <linux/pm_qos_params.h>
>
> #define snd_pcm_substream_chip(substream) ((substream)->private_data)
> #define snd_pcm_chip(pcm) ((pcm)->private_data)
> @@ -365,7 +366,7 @@ struct snd_pcm_substream {
> int number;
> char name[32]; /* substream name */
> int stream; /* stream (direction) */
> - char latency_id[20]; /* latency identifier */
> + struct pm_qos_request_list *latency_pm_qos_req; /* pm_qos request */
> size_t buffer_bytes_max; /* limit ring buffer size */
> struct snd_dma_buffer dma_buffer;
> unsigned int dma_buf_id;
> diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
> index 3db49b9..dfa1425 100644
> --- a/kernel/pm_qos_params.c
> +++ b/kernel/pm_qos_params.c
> @@ -2,7 +2,7 @@
> * This module exposes the interface to kernel space for specifying
> * QoS dependencies. It provides infrastructure for registration of:
> *
> - * Dependents on a QoS value : register requirements
> + * Dependents on a QoS value : register requests
> * Watchers of QoS value : get notified when target QoS value changes
> *
> * This QoS design is best effort based. Dependents register their QoS needs.
> @@ -14,19 +14,21 @@
> * timeout: usec <-- currently not used.
> * throughput: kbs (kilo byte / sec)
> *
> - * There are lists of pm_qos_objects each one wrapping requirements, notifiers
> + * There are lists of pm_qos_objects each one wrapping requests, notifiers
> *
> - * User mode requirements on a QOS parameter register themselves to the
> + * User mode requests on a QOS parameter register themselves to the
> * subsystem by opening the device node /dev/... and writing there request to
> * the node. As long as the process holds a file handle open to the node the
> * client continues to be accounted for. Upon file release the usermode
> - * requirement is removed and a new qos target is computed. This way when the
> - * requirement that the application has is cleaned up when closes the file
> + * request is removed and a new qos target is computed. This way when the
> + * request that the application has is cleaned up when closes the file
> * pointer or exits the pm_qos_object will get an opportunity to clean up.
> *
> * Mark Gross <mgross@xxxxxxxxxxxxxxx>
> */
>
> +/*#define DEBUG*/
> +
> #include <linux/pm_qos_params.h>
> #include <linux/sched.h>
> #include <linux/spinlock.h>
> @@ -42,25 +44,25 @@
> #include <linux/uaccess.h>
>
> /*
> - * locking rule: all changes to requirements or notifiers lists
> + * locking rule: all changes to requests or notifiers lists
> * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
> * held, taken with _irqsave. One lock to rule them all
> */
> -struct requirement_list {
> +struct pm_qos_request_list {
> struct list_head list;
> union {
> s32 value;
> s32 usec;
> s32 kbps;
> };
> - char *name;
> + int pm_qos_class;
> };
>
> static s32 max_compare(s32 v1, s32 v2);
> static s32 min_compare(s32 v1, s32 v2);
>
> struct pm_qos_object {
> - struct requirement_list requirements;
> + struct pm_qos_request_list requests;
> struct blocking_notifier_head *notifiers;
> struct miscdevice pm_qos_power_miscdev;
> char *name;
> @@ -72,7 +74,7 @@ struct pm_qos_object {
> static struct pm_qos_object null_pm_qos;
> static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
> static struct pm_qos_object cpu_dma_pm_qos = {
> - .requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
> + .requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
> .notifiers = &cpu_dma_lat_notifier,
> .name = "cpu_dma_latency",
> .default_value = 2000 * USEC_PER_SEC,
> @@ -82,7 +84,7 @@ static struct pm_qos_object cpu_dma_pm_qos = {
>
> static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
> static struct pm_qos_object network_lat_pm_qos = {
> - .requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
> + .requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
> .notifiers = &network_lat_notifier,
> .name = "network_latency",
> .default_value = 2000 * USEC_PER_SEC,
> @@ -93,8 +95,7 @@ static struct pm_qos_object network_lat_pm_qos = {
>
> static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
> static struct pm_qos_object network_throughput_pm_qos = {
> - .requirements =
> - {LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
> + .requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
> .notifiers = &network_throughput_notifier,
> .name = "network_throughput",
> .default_value = 0,
> @@ -135,31 +136,34 @@ static s32 min_compare(s32 v1, s32 v2)
> }
>
>
> -static void update_target(int target)
> +static void update_target(int pm_qos_class)
> {
> s32 extreme_value;
> - struct requirement_list *node;
> + struct pm_qos_request_list *node;
> unsigned long flags;
> int call_notifier = 0;
>
> spin_lock_irqsave(&pm_qos_lock, flags);
> - extreme_value = pm_qos_array[target]->default_value;
> + extreme_value = pm_qos_array[pm_qos_class]->default_value;
> list_for_each_entry(node,
> - &pm_qos_array[target]->requirements.list, list) {
> - extreme_value = pm_qos_array[target]->comparitor(
> + &pm_qos_array[pm_qos_class]->requests.list, list) {
> + extreme_value = pm_qos_array[pm_qos_class]->comparitor(
> extreme_value, node->value);
> }
> - if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
> + if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
> + extreme_value) {
> call_notifier = 1;
> - atomic_set(&pm_qos_array[target]->target_value, extreme_value);
> - pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
> - atomic_read(&pm_qos_array[target]->target_value));
> + atomic_set(&pm_qos_array[pm_qos_class]->target_value,
> + extreme_value);
> + pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
> + atomic_read(&pm_qos_array[pm_qos_class]->target_value));
> }
> spin_unlock_irqrestore(&pm_qos_lock, flags);
>
> if (call_notifier)
> - blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
> - (unsigned long) extreme_value, NULL);
> + blocking_notifier_call_chain(
> + pm_qos_array[pm_qos_class]->notifiers,
> + (unsigned long) extreme_value, NULL);
> }
>
> static int register_pm_qos_misc(struct pm_qos_object *qos)
> @@ -185,125 +189,113 @@ static int find_pm_qos_object_by_minor(int minor)
> }
>
> /**
> - * pm_qos_requirement - returns current system wide qos expectation
> + * pm_qos_request - returns current system wide qos expectation
> * @pm_qos_class: identification of which qos value is requested
> *
> * This function returns the current target value in an atomic manner.
> */
> -int pm_qos_requirement(int pm_qos_class)
> +int pm_qos_request(int pm_qos_class)
> {
> return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
> }
> -EXPORT_SYMBOL_GPL(pm_qos_requirement);
> +EXPORT_SYMBOL_GPL(pm_qos_request);
>
> /**
> - * pm_qos_add_requirement - inserts new qos request into the list
> + * pm_qos_add_request - inserts new qos request into the list
> * @pm_qos_class: identifies which list of qos request to us
> - * @name: identifies the request
> * @value: defines the qos request
> *
> * This function inserts a new entry in the pm_qos_class list of requested qos
> * performance characteristics. It recomputes the aggregate QoS expectations
> - * for the pm_qos_class of parameters.
> + * for the pm_qos_class of parameters, and returns the pm_qos_request list
> + * element as a handle for use in updating and removal. Call needs to save
> + * this handle for later use.
> */
> -int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
> +struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
> {
> - struct requirement_list *dep;
> + struct pm_qos_request_list *dep;
> unsigned long flags;
>
> - dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
> + dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
> if (dep) {
> if (value == PM_QOS_DEFAULT_VALUE)
> dep->value = pm_qos_array[pm_qos_class]->default_value;
> else
> dep->value = value;
> - dep->name = kstrdup(name, GFP_KERNEL);
> - if (!dep->name)
> - goto cleanup;
> + dep->pm_qos_class = pm_qos_class;
>
> spin_lock_irqsave(&pm_qos_lock, flags);
> list_add(&dep->list,
> - &pm_qos_array[pm_qos_class]->requirements.list);
> + &pm_qos_array[pm_qos_class]->requests.list);
> spin_unlock_irqrestore(&pm_qos_lock, flags);
> update_target(pm_qos_class);
> -
> - return 0;
> }
>
> -cleanup:
> - kfree(dep);
> - return -ENOMEM;
> + return dep;
> }
> -EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
> +EXPORT_SYMBOL_GPL(pm_qos_add_request);
>
> /**
> - * pm_qos_update_requirement - modifies an existing qos request
> - * @pm_qos_class: identifies which list of qos request to us
> - * @name: identifies the request
> + * pm_qos_update_request - modifies an existing qos request
> + * @pm_qos_req : handle to list element holding a pm_qos request to use
> * @value: defines the qos request
> *
> - * Updates an existing qos requirement for the pm_qos_class of parameters along
> + * Updates an existing qos request for the pm_qos_class of parameters along
> * with updating the target pm_qos_class value.
> *
> - * If the named request isn't in the list then no change is made.
> + * Attempts are made to make this code callable on hot code paths.
> */
> -int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
> +void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
> + s32 new_value)
> {
> unsigned long flags;
> - struct requirement_list *node;
> int pending_update = 0;
> + s32 temp;
>
> - spin_lock_irqsave(&pm_qos_lock, flags);
> - list_for_each_entry(node,
> - &pm_qos_array[pm_qos_class]->requirements.list, list) {
> - if (strcmp(node->name, name) == 0) {
> - if (new_value == PM_QOS_DEFAULT_VALUE)
> - node->value =
> - pm_qos_array[pm_qos_class]->default_value;
> - else
> - node->value = new_value;
> + if (pm_qos_req) { /*guard against callers passing in null */
> + spin_lock_irqsave(&pm_qos_lock, flags);
> + if (new_value == PM_QOS_DEFAULT_VALUE)
> + temp = pm_qos_array[pm_qos_req->pm_qos_class]->
> + default_value;
> + else
> + temp = new_value;
> +
> + if (temp != pm_qos_req->value) {
> pending_update = 1;
> - break;
> + pm_qos_req->value = temp;
> }
> + spin_unlock_irqrestore(&pm_qos_lock, flags);
> }
> - spin_unlock_irqrestore(&pm_qos_lock, flags);
> if (pending_update)
> - update_target(pm_qos_class);
> -
> - return 0;
> + update_target(pm_qos_req->pm_qos_class);
> }
> -EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
> +EXPORT_SYMBOL_GPL(pm_qos_update_request);
>
> /**
> - * pm_qos_remove_requirement - modifies an existing qos request
> - * @pm_qos_class: identifies which list of qos request to us
> - * @name: identifies the request
> + * pm_qos_remove_request - modifies an existing qos request
> + * @pm_qos_req: handle to request list element
> *
> - * Will remove named qos request from pm_qos_class list of parameters and
> - * recompute the current target value for the pm_qos_class.
> + * Will remove pm qos request from the list of requests and
> + * recompute the current target value for the pm_qos_class. Call this
> + * on slow code paths.
> */
> -void pm_qos_remove_requirement(int pm_qos_class, char *name)
> +void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
> {
> unsigned long flags;
> - struct requirement_list *node;
> - int pending_update = 0;
> + int qos_class;
> +
> + if (pm_qos_req == NULL)
> + return;
> + /* silent return to keep pcm code cleaner */
>
> + qos_class = pm_qos_req->pm_qos_class;
> spin_lock_irqsave(&pm_qos_lock, flags);
> - list_for_each_entry(node,
> - &pm_qos_array[pm_qos_class]->requirements.list, list) {
> - if (strcmp(node->name, name) == 0) {
> - kfree(node->name);
> - list_del(&node->list);
> - kfree(node);
> - pending_update = 1;
> - break;
> - }
> - }
> + list_del(&pm_qos_req->list);
> + kfree(pm_qos_req);
> spin_unlock_irqrestore(&pm_qos_lock, flags);
> - if (pending_update)
> - update_target(pm_qos_class);
> + update_target(qos_class);
> }
> -EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
> +EXPORT_SYMBOL_GPL(pm_qos_remove_request);
>
> /**
> * pm_qos_add_notifier - sets notification entry for changes to target value
> @@ -313,7 +305,7 @@ EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
> * will register the notifier into a notification chain that gets called
> * upon changes to the pm_qos_class target value.
> */
> - int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
> +int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
> {
> int retval;
>
> @@ -343,21 +335,16 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
> }
> EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
>
> -#define PID_NAME_LEN 32
> -
> static int pm_qos_power_open(struct inode *inode, struct file *filp)
> {
> - int ret;
> long pm_qos_class;
> - char name[PID_NAME_LEN];
>
> pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
> if (pm_qos_class >= 0) {
> - filp->private_data = (void *)pm_qos_class;
> - snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
> - ret = pm_qos_add_requirement(pm_qos_class, name,
> - PM_QOS_DEFAULT_VALUE);
> - if (ret >= 0)
> + filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
> + PM_QOS_DEFAULT_VALUE);
> +
> + if (filp->private_data)
> return 0;
> }
> return -EPERM;
> @@ -365,32 +352,40 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp)
>
> static int pm_qos_power_release(struct inode *inode, struct file *filp)
> {
> - int pm_qos_class;
> - char name[PID_NAME_LEN];
> + struct pm_qos_request_list *req;
>
> - pm_qos_class = (long)filp->private_data;
> - snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
> - pm_qos_remove_requirement(pm_qos_class, name);
> + req = (struct pm_qos_request_list *)filp->private_data;
> + pm_qos_remove_request(req);
>
> return 0;
> }
>
> +
> static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
> size_t count, loff_t *f_pos)
> {
> s32 value;
> - int pm_qos_class;
> - char name[PID_NAME_LEN];
> -
> - pm_qos_class = (long)filp->private_data;
> - if (count != sizeof(s32))
> + int x;
> + char ascii_value[11];
> + struct pm_qos_request_list *pm_qos_req;
> +
> + if (count == sizeof(s32)) {
> + if (copy_from_user(&value, buf, sizeof(s32)))
> + return -EFAULT;
> + } else if (count == 11) { /* len('0x12345678/0') */
> + if (copy_from_user(ascii_value, buf, 11))
> + return -EFAULT;
> + x = sscanf(ascii_value, "%x", &value);
> + if (x != 1)
> + return -EINVAL;
> + pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
> + } else
> return -EINVAL;
> - if (copy_from_user(&value, buf, sizeof(s32)))
> - return -EFAULT;
> - snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
> - pm_qos_update_requirement(pm_qos_class, name, value);
>
> - return sizeof(s32);
> + pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
> + pm_qos_update_request(pm_qos_req, value);
> +
> + return count;
> }
>
>
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index 875c8de..88f95e7 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -495,7 +495,7 @@ void ieee80211_recalc_ps(struct ieee80211_local *local, s32 latency)
> s32 beaconint_us;
>
> if (latency < 0)
> - latency = pm_qos_requirement(PM_QOS_NETWORK_LATENCY);
> + latency = pm_qos_request(PM_QOS_NETWORK_LATENCY);
>
> beaconint_us = ieee80211_tu_to_usec(
> found->vif.bss_conf.beacon_int);
> diff --git a/sound/core/pcm.c b/sound/core/pcm.c
> index 0d428d0..cbe815d 100644
> --- a/sound/core/pcm.c
> +++ b/sound/core/pcm.c
> @@ -648,9 +648,6 @@ int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
> substream->number = idx;
> substream->stream = stream;
> sprintf(substream->name, "subdevice #%i", idx);
> - snprintf(substream->latency_id, sizeof(substream->latency_id),
> - "ALSA-PCM%d-%d%c%d", pcm->card->number, pcm->device,
> - (stream ? 'c' : 'p'), idx);
> substream->buffer_bytes_max = UINT_MAX;
> if (prev == NULL)
> pstr->substream = substream;
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index 20b5982..192dd40 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -484,11 +484,13 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
> snd_pcm_timer_resolution_change(substream);
> runtime->status->state = SNDRV_PCM_STATE_SETUP;
>
> - pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
> - substream->latency_id);
> + if (substream->latency_pm_qos_req) {
> + pm_qos_remove_request(substream->latency_pm_qos_req);
> + substream->latency_pm_qos_req = NULL;
> + }
> if ((usecs = period_to_usecs(runtime)) >= 0)
> - pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
> - substream->latency_id, usecs);
> + substream->latency_pm_qos_req = pm_qos_add_request(
> + PM_QOS_CPU_DMA_LATENCY, usecs);
> return 0;
> _error:
> /* hardware might be unuseable from this time,
> @@ -543,8 +545,8 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
> if (substream->ops->hw_free)
> result = substream->ops->hw_free(substream);
> runtime->status->state = SNDRV_PCM_STATE_OPEN;
> - pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
> - substream->latency_id);
> + pm_qos_remove_request(substream->latency_pm_qos_req);
> + substream->latency_pm_qos_req = NULL;
> return result;
> }
>
>
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