Revision c1230df7e19e0f27655c0eb9d966c7e03be7cc50 authored by Paulo Zanoni on 03 May 2012, 01:55:43 UTC, committed by Daniel Vetter on 03 May 2012, 13:55:38 UTC
While testing with the intel_infoframes tool on gen4, I see that when video DIP is disabled, what we write to the DATA memory is not exactly what we read back later. This regression has been introduce in commit 64a8fc0145a1d0fdc25fc9367c2e6c621955fb3b Author: Jesse Barnes <jbarnes@virtuousgeek.org> Date: Thu Sep 22 11:16:00 2011 +0530 drm/i915: fix ILK+ infoframe support That commit was setting VIDEO_DIP_CTL to 0 when initializing, which caused the problem. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=43947 Cc: stable@kernel.org Tested-by: Yang Guang <guang.a.yang@intel.com> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com> [danvet: Pimped commit message by using the usual commit citation layout.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 parent 6200497
blk-ioc.c
/*
* Functions related to io context handling
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
#include <linux/slab.h>
#include "blk.h"
/*
* For io context allocations
*/
static struct kmem_cache *iocontext_cachep;
/**
* get_io_context - increment reference count to io_context
* @ioc: io_context to get
*
* Increment reference count to @ioc.
*/
void get_io_context(struct io_context *ioc)
{
BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
atomic_long_inc(&ioc->refcount);
}
EXPORT_SYMBOL(get_io_context);
static void icq_free_icq_rcu(struct rcu_head *head)
{
struct io_cq *icq = container_of(head, struct io_cq, __rcu_head);
kmem_cache_free(icq->__rcu_icq_cache, icq);
}
/* Exit an icq. Called with both ioc and q locked. */
static void ioc_exit_icq(struct io_cq *icq)
{
struct elevator_type *et = icq->q->elevator->type;
if (icq->flags & ICQ_EXITED)
return;
if (et->ops.elevator_exit_icq_fn)
et->ops.elevator_exit_icq_fn(icq);
icq->flags |= ICQ_EXITED;
}
/* Release an icq. Called with both ioc and q locked. */
static void ioc_destroy_icq(struct io_cq *icq)
{
struct io_context *ioc = icq->ioc;
struct request_queue *q = icq->q;
struct elevator_type *et = q->elevator->type;
lockdep_assert_held(&ioc->lock);
lockdep_assert_held(q->queue_lock);
radix_tree_delete(&ioc->icq_tree, icq->q->id);
hlist_del_init(&icq->ioc_node);
list_del_init(&icq->q_node);
/*
* Both setting lookup hint to and clearing it from @icq are done
* under queue_lock. If it's not pointing to @icq now, it never
* will. Hint assignment itself can race safely.
*/
if (rcu_dereference_raw(ioc->icq_hint) == icq)
rcu_assign_pointer(ioc->icq_hint, NULL);
ioc_exit_icq(icq);
/*
* @icq->q might have gone away by the time RCU callback runs
* making it impossible to determine icq_cache. Record it in @icq.
*/
icq->__rcu_icq_cache = et->icq_cache;
call_rcu(&icq->__rcu_head, icq_free_icq_rcu);
}
/*
* Slow path for ioc release in put_io_context(). Performs double-lock
* dancing to unlink all icq's and then frees ioc.
*/
static void ioc_release_fn(struct work_struct *work)
{
struct io_context *ioc = container_of(work, struct io_context,
release_work);
unsigned long flags;
/*
* Exiting icq may call into put_io_context() through elevator
* which will trigger lockdep warning. The ioc's are guaranteed to
* be different, use a different locking subclass here. Use
* irqsave variant as there's no spin_lock_irq_nested().
*/
spin_lock_irqsave_nested(&ioc->lock, flags, 1);
while (!hlist_empty(&ioc->icq_list)) {
struct io_cq *icq = hlist_entry(ioc->icq_list.first,
struct io_cq, ioc_node);
struct request_queue *q = icq->q;
if (spin_trylock(q->queue_lock)) {
ioc_destroy_icq(icq);
spin_unlock(q->queue_lock);
} else {
spin_unlock_irqrestore(&ioc->lock, flags);
cpu_relax();
spin_lock_irqsave_nested(&ioc->lock, flags, 1);
}
}
spin_unlock_irqrestore(&ioc->lock, flags);
kmem_cache_free(iocontext_cachep, ioc);
}
/**
* put_io_context - put a reference of io_context
* @ioc: io_context to put
*
* Decrement reference count of @ioc and release it if the count reaches
* zero.
*/
void put_io_context(struct io_context *ioc)
{
unsigned long flags;
bool free_ioc = false;
if (ioc == NULL)
return;
BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
/*
* Releasing ioc requires reverse order double locking and we may
* already be holding a queue_lock. Do it asynchronously from wq.
*/
if (atomic_long_dec_and_test(&ioc->refcount)) {
spin_lock_irqsave(&ioc->lock, flags);
if (!hlist_empty(&ioc->icq_list))
schedule_work(&ioc->release_work);
else
free_ioc = true;
spin_unlock_irqrestore(&ioc->lock, flags);
}
if (free_ioc)
kmem_cache_free(iocontext_cachep, ioc);
}
EXPORT_SYMBOL(put_io_context);
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
{
struct io_context *ioc;
struct io_cq *icq;
struct hlist_node *n;
unsigned long flags;
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
if (!atomic_dec_and_test(&ioc->nr_tasks)) {
put_io_context(ioc);
return;
}
/*
* Need ioc lock to walk icq_list and q lock to exit icq. Perform
* reverse double locking. Read comment in ioc_release_fn() for
* explanation on the nested locking annotation.
*/
retry:
spin_lock_irqsave_nested(&ioc->lock, flags, 1);
hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node) {
if (icq->flags & ICQ_EXITED)
continue;
if (spin_trylock(icq->q->queue_lock)) {
ioc_exit_icq(icq);
spin_unlock(icq->q->queue_lock);
} else {
spin_unlock_irqrestore(&ioc->lock, flags);
cpu_relax();
goto retry;
}
}
spin_unlock_irqrestore(&ioc->lock, flags);
put_io_context(ioc);
}
/**
* ioc_clear_queue - break any ioc association with the specified queue
* @q: request_queue being cleared
*
* Walk @q->icq_list and exit all io_cq's. Must be called with @q locked.
*/
void ioc_clear_queue(struct request_queue *q)
{
lockdep_assert_held(q->queue_lock);
while (!list_empty(&q->icq_list)) {
struct io_cq *icq = list_entry(q->icq_list.next,
struct io_cq, q_node);
struct io_context *ioc = icq->ioc;
spin_lock(&ioc->lock);
ioc_destroy_icq(icq);
spin_unlock(&ioc->lock);
}
}
void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
int node)
{
struct io_context *ioc;
ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
node);
if (unlikely(!ioc))
return;
/* initialize */
atomic_long_set(&ioc->refcount, 1);
atomic_set(&ioc->nr_tasks, 1);
spin_lock_init(&ioc->lock);
INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
INIT_HLIST_HEAD(&ioc->icq_list);
INIT_WORK(&ioc->release_work, ioc_release_fn);
/*
* Try to install. ioc shouldn't be installed if someone else
* already did or @task, which isn't %current, is exiting. Note
* that we need to allow ioc creation on exiting %current as exit
* path may issue IOs from e.g. exit_files(). The exit path is
* responsible for not issuing IO after exit_io_context().
*/
task_lock(task);
if (!task->io_context &&
(task == current || !(task->flags & PF_EXITING)))
task->io_context = ioc;
else
kmem_cache_free(iocontext_cachep, ioc);
task_unlock(task);
}
/**
* get_task_io_context - get io_context of a task
* @task: task of interest
* @gfp_flags: allocation flags, used if allocation is necessary
* @node: allocation node, used if allocation is necessary
*
* Return io_context of @task. If it doesn't exist, it is created with
* @gfp_flags and @node. The returned io_context has its reference count
* incremented.
*
* This function always goes through task_lock() and it's better to use
* %current->io_context + get_io_context() for %current.
*/
struct io_context *get_task_io_context(struct task_struct *task,
gfp_t gfp_flags, int node)
{
struct io_context *ioc;
might_sleep_if(gfp_flags & __GFP_WAIT);
do {
task_lock(task);
ioc = task->io_context;
if (likely(ioc)) {
get_io_context(ioc);
task_unlock(task);
return ioc;
}
task_unlock(task);
} while (create_io_context(task, gfp_flags, node));
return NULL;
}
EXPORT_SYMBOL(get_task_io_context);
/**
* ioc_lookup_icq - lookup io_cq from ioc
* @ioc: the associated io_context
* @q: the associated request_queue
*
* Look up io_cq associated with @ioc - @q pair from @ioc. Must be called
* with @q->queue_lock held.
*/
struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q)
{
struct io_cq *icq;
lockdep_assert_held(q->queue_lock);
/*
* icq's are indexed from @ioc using radix tree and hint pointer,
* both of which are protected with RCU. All removals are done
* holding both q and ioc locks, and we're holding q lock - if we
* find a icq which points to us, it's guaranteed to be valid.
*/
rcu_read_lock();
icq = rcu_dereference(ioc->icq_hint);
if (icq && icq->q == q)
goto out;
icq = radix_tree_lookup(&ioc->icq_tree, q->id);
if (icq && icq->q == q)
rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
else
icq = NULL;
out:
rcu_read_unlock();
return icq;
}
EXPORT_SYMBOL(ioc_lookup_icq);
/**
* ioc_create_icq - create and link io_cq
* @q: request_queue of interest
* @gfp_mask: allocation mask
*
* Make sure io_cq linking %current->io_context and @q exists. If either
* io_context and/or icq don't exist, they will be created using @gfp_mask.
*
* The caller is responsible for ensuring @ioc won't go away and @q is
* alive and will stay alive until this function returns.
*/
struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
{
struct elevator_type *et = q->elevator->type;
struct io_context *ioc;
struct io_cq *icq;
/* allocate stuff */
ioc = create_io_context(current, gfp_mask, q->node);
if (!ioc)
return NULL;
icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
q->node);
if (!icq)
return NULL;
if (radix_tree_preload(gfp_mask) < 0) {
kmem_cache_free(et->icq_cache, icq);
return NULL;
}
icq->ioc = ioc;
icq->q = q;
INIT_LIST_HEAD(&icq->q_node);
INIT_HLIST_NODE(&icq->ioc_node);
/* lock both q and ioc and try to link @icq */
spin_lock_irq(q->queue_lock);
spin_lock(&ioc->lock);
if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) {
hlist_add_head(&icq->ioc_node, &ioc->icq_list);
list_add(&icq->q_node, &q->icq_list);
if (et->ops.elevator_init_icq_fn)
et->ops.elevator_init_icq_fn(icq);
} else {
kmem_cache_free(et->icq_cache, icq);
icq = ioc_lookup_icq(ioc, q);
if (!icq)
printk(KERN_ERR "cfq: icq link failed!\n");
}
spin_unlock(&ioc->lock);
spin_unlock_irq(q->queue_lock);
radix_tree_preload_end();
return icq;
}
void ioc_set_icq_flags(struct io_context *ioc, unsigned int flags)
{
struct io_cq *icq;
struct hlist_node *n;
hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
icq->flags |= flags;
}
/**
* ioc_ioprio_changed - notify ioprio change
* @ioc: io_context of interest
* @ioprio: new ioprio
*
* @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
* icq's. iosched is responsible for checking the bit and applying it on
* request issue path.
*/
void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
{
unsigned long flags;
spin_lock_irqsave(&ioc->lock, flags);
ioc->ioprio = ioprio;
ioc_set_icq_flags(ioc, ICQ_IOPRIO_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}
/**
* ioc_cgroup_changed - notify cgroup change
* @ioc: io_context of interest
*
* @ioc's cgroup has changed. Set %ICQ_CGROUP_CHANGED for all icq's.
* iosched is responsible for checking the bit and applying it on request
* issue path.
*/
void ioc_cgroup_changed(struct io_context *ioc)
{
unsigned long flags;
spin_lock_irqsave(&ioc->lock, flags);
ioc_set_icq_flags(ioc, ICQ_CGROUP_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}
EXPORT_SYMBOL(ioc_cgroup_changed);
/**
* icq_get_changed - fetch and clear icq changed mask
* @icq: icq of interest
*
* Fetch and clear ICQ_*_CHANGED bits from @icq. Grabs and releases
* @icq->ioc->lock.
*/
unsigned icq_get_changed(struct io_cq *icq)
{
unsigned int changed = 0;
unsigned long flags;
if (unlikely(icq->flags & ICQ_CHANGED_MASK)) {
spin_lock_irqsave(&icq->ioc->lock, flags);
changed = icq->flags & ICQ_CHANGED_MASK;
icq->flags &= ~ICQ_CHANGED_MASK;
spin_unlock_irqrestore(&icq->ioc->lock, flags);
}
return changed;
}
EXPORT_SYMBOL(icq_get_changed);
static int __init blk_ioc_init(void)
{
iocontext_cachep = kmem_cache_create("blkdev_ioc",
sizeof(struct io_context), 0, SLAB_PANIC, NULL);
return 0;
}
subsys_initcall(blk_ioc_init);
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