Merge remote-tracking branch 'airlied/drm-fixes' into drm-intel-next-queued

Back-merge from drm-fixes into drm-intel-next to sort out two things:

- interlaced support: -fixes contains a bugfix to correctly clear
  interlaced configuration bits in case the bios sets up an interlaced
  mode and we want to set up the progressive mode (current kernels
  don't support interlaced). The actual feature work to support
  interlaced depends upon (and conflicts with) this bugfix.

- forcewake voodoo to workaround missed IRQ issues: -fixes only enabled
  this for ivybridge, but some recent bug reports indicate that we
  need this on Sandybridge, too. But in a slightly different flavour
  and with other fixes and reworks on top. Additionally there are some
  forcewake cleanup patches heading to -next that would conflict with
  currrent -fixes.

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 95 insertions, 41 deletions

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 5037a0ad2312..7e1371c4bccf 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -3,32 +3,92 @@
 
 #include <linux/radix-tree.h>
 #include <linux/rcupdate.h>
+#include <linux/workqueue.h>
 
-struct cfq_queue;
-struct cfq_ttime {
-	unsigned long last_end_request;
-
-	unsigned long ttime_total;
-	unsigned long ttime_samples;
-	unsigned long ttime_mean;
+enum {
+	ICQ_IOPRIO_CHANGED,
+	ICQ_CGROUP_CHANGED,
 };
 
-struct cfq_io_context {
-	void *key;
-
-	struct cfq_queue *cfqq[2];
-
-	struct io_context *ioc;
-
-	struct cfq_ttime ttime;
-
-	struct list_head queue_list;
-	struct hlist_node cic_list;
-
-	void (*dtor)(struct io_context *); /* destructor */
-	void (*exit)(struct io_context *); /* called on task exit */
+/*
+ * An io_cq (icq) is association between an io_context (ioc) and a
+ * request_queue (q).  This is used by elevators which need to track
+ * information per ioc - q pair.
+ *
+ * Elevator can request use of icq by setting elevator_type->icq_size and
+ * ->icq_align.  Both size and align must be larger than that of struct
+ * io_cq and elevator can use the tail area for private information.  The
+ * recommended way to do this is defining a struct which contains io_cq as
+ * the first member followed by private members and using its size and
+ * align.  For example,
+ *
+ *	struct snail_io_cq {
+ *		struct io_cq	icq;
+ *		int		poke_snail;
+ *		int		feed_snail;
+ *	};
+ *
+ *	struct elevator_type snail_elv_type {
+ *		.ops =		{ ... },
+ *		.icq_size =	sizeof(struct snail_io_cq),
+ *		.icq_align =	__alignof__(struct snail_io_cq),
+ *		...
+ *	};
+ *
+ * If icq_size is set, block core will manage icq's.  All requests will
+ * have its ->elv.icq field set before elevator_ops->elevator_set_req_fn()
+ * is called and be holding a reference to the associated io_context.
+ *
+ * Whenever a new icq is created, elevator_ops->elevator_init_icq_fn() is
+ * called and, on destruction, ->elevator_exit_icq_fn().  Both functions
+ * are called with both the associated io_context and queue locks held.
+ *
+ * Elevator is allowed to lookup icq using ioc_lookup_icq() while holding
+ * queue lock but the returned icq is valid only until the queue lock is
+ * released.  Elevators can not and should not try to create or destroy
+ * icq's.
+ *
+ * As icq's are linked from both ioc and q, the locking rules are a bit
+ * complex.
+ *
+ * - ioc lock nests inside q lock.
+ *
+ * - ioc->icq_list and icq->ioc_node are protected by ioc lock.
+ *   q->icq_list and icq->q_node by q lock.
+ *
+ * - ioc->icq_tree and ioc->icq_hint are protected by ioc lock, while icq
+ *   itself is protected by q lock.  However, both the indexes and icq
+ *   itself are also RCU managed and lookup can be performed holding only
+ *   the q lock.
+ *
+ * - icq's are not reference counted.  They are destroyed when either the
+ *   ioc or q goes away.  Each request with icq set holds an extra
+ *   reference to ioc to ensure it stays until the request is completed.
+ *
+ * - Linking and unlinking icq's are performed while holding both ioc and q
+ *   locks.  Due to the lock ordering, q exit is simple but ioc exit
+ *   requires reverse-order double lock dance.
+ */
+struct io_cq {
+	struct request_queue	*q;
+	struct io_context	*ioc;
 
-	struct rcu_head rcu_head;
+	/*
+	 * q_node and ioc_node link io_cq through icq_list of q and ioc
+	 * respectively.  Both fields are unused once ioc_exit_icq() is
+	 * called and shared with __rcu_icq_cache and __rcu_head which are
+	 * used for RCU free of io_cq.
+	 */
+	union {
+		struct list_head	q_node;
+		struct kmem_cache	*__rcu_icq_cache;
+	};
+	union {
+		struct hlist_node	ioc_node;
+		struct rcu_head		__rcu_head;
+	};
+
+	unsigned long		changed;
 };
 
 /*
@@ -43,11 +103,6 @@ struct io_context {
 	spinlock_t lock;
 
 	unsigned short ioprio;
-	unsigned short ioprio_changed;
-
-#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
-	unsigned short cgroup_changed;
-#endif
 
 	/*
 	 * For request batching
@@ -55,9 +110,11 @@ struct io_context {
 	int nr_batch_requests;     /* Number of requests left in the batch */
 	unsigned long last_waited; /* Time last woken after wait for request */
 
-	struct radix_tree_root radix_root;
-	struct hlist_head cic_list;
-	void __rcu *ioc_data;
+	struct radix_tree_root	icq_tree;
+	struct io_cq __rcu	*icq_hint;
+	struct hlist_head	icq_list;
+
+	struct work_struct release_work;
 };
 
 static inline struct io_context *ioc_task_link(struct io_context *ioc)
@@ -76,20 +133,17 @@ static inline struct io_context *ioc_task_link(struct io_context *ioc)
 
 struct task_struct;
 #ifdef CONFIG_BLOCK
-int put_io_context(struct io_context *ioc);
+void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
 void exit_io_context(struct task_struct *task);
-struct io_context *get_io_context(gfp_t gfp_flags, int node);
-struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
+struct io_context *get_task_io_context(struct task_struct *task,
+				       gfp_t gfp_flags, int node);
+void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
+void ioc_cgroup_changed(struct io_context *ioc);
 #else
-static inline void exit_io_context(struct task_struct *task)
-{
-}
-
 struct io_context;
-static inline int put_io_context(struct io_context *ioc)
-{
-	return 1;
-}
+static inline void put_io_context(struct io_context *ioc,
+				  struct request_queue *locked_q) { }
+static inline void exit_io_context(struct task_struct *task) { }
 #endif
 
 #endif