summaryrefslogtreecommitdiff
path: root/block/blk-iopoll.c
diff options
context:
space:
mode:
Diffstat (limited to 'block/blk-iopoll.c')
-rw-r--r--block/blk-iopoll.c224
1 files changed, 0 insertions, 224 deletions
diff --git a/block/blk-iopoll.c b/block/blk-iopoll.c
deleted file mode 100644
index 0736729d6..000000000
--- a/block/blk-iopoll.c
+++ /dev/null
@@ -1,224 +0,0 @@
-/*
- * Functions related to interrupt-poll handling in the block layer. This
- * is similar to NAPI for network devices.
- */
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/bio.h>
-#include <linux/blkdev.h>
-#include <linux/interrupt.h>
-#include <linux/cpu.h>
-#include <linux/blk-iopoll.h>
-#include <linux/delay.h>
-
-#include "blk.h"
-
-static unsigned int blk_iopoll_budget __read_mostly = 256;
-
-static DEFINE_PER_CPU(struct list_head, blk_cpu_iopoll);
-
-/**
- * blk_iopoll_sched - Schedule a run of the iopoll handler
- * @iop: The parent iopoll structure
- *
- * Description:
- * Add this blk_iopoll structure to the pending poll list and trigger the
- * raise of the blk iopoll softirq. The driver must already have gotten a
- * successful return from blk_iopoll_sched_prep() before calling this.
- **/
-void blk_iopoll_sched(struct blk_iopoll *iop)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- list_add_tail(&iop->list, this_cpu_ptr(&blk_cpu_iopoll));
- __raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
- local_irq_restore(flags);
-}
-EXPORT_SYMBOL(blk_iopoll_sched);
-
-/**
- * __blk_iopoll_complete - Mark this @iop as un-polled again
- * @iop: The parent iopoll structure
- *
- * Description:
- * See blk_iopoll_complete(). This function must be called with interrupts
- * disabled.
- **/
-void __blk_iopoll_complete(struct blk_iopoll *iop)
-{
- list_del(&iop->list);
- smp_mb__before_atomic();
- clear_bit_unlock(IOPOLL_F_SCHED, &iop->state);
-}
-EXPORT_SYMBOL(__blk_iopoll_complete);
-
-/**
- * blk_iopoll_complete - Mark this @iop as un-polled again
- * @iop: The parent iopoll structure
- *
- * Description:
- * If a driver consumes less than the assigned budget in its run of the
- * iopoll handler, it'll end the polled mode by calling this function. The
- * iopoll handler will not be invoked again before blk_iopoll_sched_prep()
- * is called.
- **/
-void blk_iopoll_complete(struct blk_iopoll *iop)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- __blk_iopoll_complete(iop);
- local_irq_restore(flags);
-}
-EXPORT_SYMBOL(blk_iopoll_complete);
-
-static void blk_iopoll_softirq(struct softirq_action *h)
-{
- struct list_head *list = this_cpu_ptr(&blk_cpu_iopoll);
- int rearm = 0, budget = blk_iopoll_budget;
- unsigned long start_time = jiffies;
-
- local_irq_disable();
-
- while (!list_empty(list)) {
- struct blk_iopoll *iop;
- int work, weight;
-
- /*
- * If softirq window is exhausted then punt.
- */
- if (budget <= 0 || time_after(jiffies, start_time)) {
- rearm = 1;
- break;
- }
-
- local_irq_enable();
-
- /* Even though interrupts have been re-enabled, this
- * access is safe because interrupts can only add new
- * entries to the tail of this list, and only ->poll()
- * calls can remove this head entry from the list.
- */
- iop = list_entry(list->next, struct blk_iopoll, list);
-
- weight = iop->weight;
- work = 0;
- if (test_bit(IOPOLL_F_SCHED, &iop->state))
- work = iop->poll(iop, weight);
-
- budget -= work;
-
- local_irq_disable();
-
- /*
- * Drivers must not modify the iopoll state, if they
- * consume their assigned weight (or more, some drivers can't
- * easily just stop processing, they have to complete an
- * entire mask of commands).In such cases this code
- * still "owns" the iopoll instance and therefore can
- * move the instance around on the list at-will.
- */
- if (work >= weight) {
- if (blk_iopoll_disable_pending(iop))
- __blk_iopoll_complete(iop);
- else
- list_move_tail(&iop->list, list);
- }
- }
-
- if (rearm)
- __raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
-
- local_irq_enable();
-}
-
-/**
- * blk_iopoll_disable - Disable iopoll on this @iop
- * @iop: The parent iopoll structure
- *
- * Description:
- * Disable io polling and wait for any pending callbacks to have completed.
- **/
-void blk_iopoll_disable(struct blk_iopoll *iop)
-{
- set_bit(IOPOLL_F_DISABLE, &iop->state);
- while (test_and_set_bit(IOPOLL_F_SCHED, &iop->state))
- msleep(1);
- clear_bit(IOPOLL_F_DISABLE, &iop->state);
-}
-EXPORT_SYMBOL(blk_iopoll_disable);
-
-/**
- * blk_iopoll_enable - Enable iopoll on this @iop
- * @iop: The parent iopoll structure
- *
- * Description:
- * Enable iopoll on this @iop. Note that the handler run will not be
- * scheduled, it will only mark it as active.
- **/
-void blk_iopoll_enable(struct blk_iopoll *iop)
-{
- BUG_ON(!test_bit(IOPOLL_F_SCHED, &iop->state));
- smp_mb__before_atomic();
- clear_bit_unlock(IOPOLL_F_SCHED, &iop->state);
-}
-EXPORT_SYMBOL(blk_iopoll_enable);
-
-/**
- * blk_iopoll_init - Initialize this @iop
- * @iop: The parent iopoll structure
- * @weight: The default weight (or command completion budget)
- * @poll_fn: The handler to invoke
- *
- * Description:
- * Initialize this blk_iopoll structure. Before being actively used, the
- * driver must call blk_iopoll_enable().
- **/
-void blk_iopoll_init(struct blk_iopoll *iop, int weight, blk_iopoll_fn *poll_fn)
-{
- memset(iop, 0, sizeof(*iop));
- INIT_LIST_HEAD(&iop->list);
- iop->weight = weight;
- iop->poll = poll_fn;
- set_bit(IOPOLL_F_SCHED, &iop->state);
-}
-EXPORT_SYMBOL(blk_iopoll_init);
-
-static int blk_iopoll_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- /*
- * If a CPU goes away, splice its entries to the current CPU
- * and trigger a run of the softirq
- */
- if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
- int cpu = (unsigned long) hcpu;
-
- local_irq_disable();
- list_splice_init(&per_cpu(blk_cpu_iopoll, cpu),
- this_cpu_ptr(&blk_cpu_iopoll));
- __raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
- local_irq_enable();
- }
-
- return NOTIFY_OK;
-}
-
-static struct notifier_block blk_iopoll_cpu_notifier = {
- .notifier_call = blk_iopoll_cpu_notify,
-};
-
-static __init int blk_iopoll_setup(void)
-{
- int i;
-
- for_each_possible_cpu(i)
- INIT_LIST_HEAD(&per_cpu(blk_cpu_iopoll, i));
-
- open_softirq(BLOCK_IOPOLL_SOFTIRQ, blk_iopoll_softirq);
- register_hotcpu_notifier(&blk_iopoll_cpu_notifier);
- return 0;
-}
-subsys_initcall(blk_iopoll_setup);