Merge branch 'blk-softirq' of git://brick.kernel.dk/data/git/linux-2.…

…6-block

Manual merge for trivial #include changes

block/ll_rw_blk.c

@@ -26,6 +26,8 @@
 #include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/writeback.h>
+#include <linux/interrupt.h>
+#include <linux/cpu.h>
 
 /*
  * for max sense size
@@ -61,13 +63,15 @@ static wait_queue_head_t congestion_wqh[2] = {
 /*
  * Controlling structure to kblockd
  */
-static struct workqueue_struct *kblockd_workqueue; 
+static struct workqueue_struct *kblockd_workqueue;
 
 unsigned long blk_max_low_pfn, blk_max_pfn;
 
 EXPORT_SYMBOL(blk_max_low_pfn);
 EXPORT_SYMBOL(blk_max_pfn);
 
+static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
+
 /* Amount of time in which a process may batch requests */
 #define BLK_BATCH_TIME	(HZ/50UL)
 
@@ -206,6 +210,13 @@ void blk_queue_merge_bvec(request_queue_t *q, merge_bvec_fn *mbfn)
 
 EXPORT_SYMBOL(blk_queue_merge_bvec);
 
+void blk_queue_softirq_done(request_queue_t *q, softirq_done_fn *fn)
+{
+	q->softirq_done_fn = fn;
+}
+
+EXPORT_SYMBOL(blk_queue_softirq_done);
+
 /**
  * blk_queue_make_request - define an alternate make_request function for a device
  * @q:  the request queue for the device to be affected
@@ -269,6 +280,7 @@ EXPORT_SYMBOL(blk_queue_make_request);
 static inline void rq_init(request_queue_t *q, struct request *rq)
 {
 	INIT_LIST_HEAD(&rq->queuelist);
+	INIT_LIST_HEAD(&rq->donelist);
 
 	rq->errors = 0;
 	rq->rq_status = RQ_ACTIVE;
@@ -285,6 +297,7 @@ static inline void rq_init(request_queue_t *q, struct request *rq)
 	rq->sense = NULL;
 	rq->end_io = NULL;
 	rq->end_io_data = NULL;
+	rq->completion_data = NULL;
 }
 
 /**
@@ -3261,6 +3274,87 @@ int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes)
 
 EXPORT_SYMBOL(end_that_request_chunk);
 
+/*
+ * splice the completion data to a local structure and hand off to
+ * process_completion_queue() to complete the requests
+ */
+static void blk_done_softirq(struct softirq_action *h)
+{
+	struct list_head *cpu_list;
+	LIST_HEAD(local_list);
+
+	local_irq_disable();
+	cpu_list = &__get_cpu_var(blk_cpu_done);
+	list_splice_init(cpu_list, &local_list);
+	local_irq_enable();
+
+	while (!list_empty(&local_list)) {
+		struct request *rq = list_entry(local_list.next, struct request, donelist);
+
+		list_del_init(&rq->donelist);
+		rq->q->softirq_done_fn(rq);
+	}
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static int blk_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) {
+		int cpu = (unsigned long) hcpu;
+
+		local_irq_disable();
+		list_splice_init(&per_cpu(blk_cpu_done, cpu),
+				 &__get_cpu_var(blk_cpu_done));
+		raise_softirq_irqoff(BLOCK_SOFTIRQ);
+		local_irq_enable();
+	}
+
+	return NOTIFY_OK;
+}
+
+
+static struct notifier_block __devinitdata blk_cpu_notifier = {
+	.notifier_call	= blk_cpu_notify,
+};
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+/**
+ * blk_complete_request - end I/O on a request
+ * @req:      the request being processed
+ *
+ * Description:
+ *     Ends all I/O on a request. It does not handle partial completions,
+ *     unless the driver actually implements this in its completionc callback
+ *     through requeueing. Theh actual completion happens out-of-order,
+ *     through a softirq handler. The user must have registered a completion
+ *     callback through blk_queue_softirq_done().
+ **/
+
+void blk_complete_request(struct request *req)
+{
+	struct list_head *cpu_list;
+	unsigned long flags;
+
+	BUG_ON(!req->q->softirq_done_fn);
+
+	local_irq_save(flags);
+
+	cpu_list = &__get_cpu_var(blk_cpu_done);
+	list_add_tail(&req->donelist, cpu_list);
+	raise_softirq_irqoff(BLOCK_SOFTIRQ);
+
+	local_irq_restore(flags);
+}
+
+EXPORT_SYMBOL(blk_complete_request);
+
 /*
  * queue lock must be held
  */
@@ -3339,6 +3433,8 @@ EXPORT_SYMBOL(kblockd_flush);
 
 int __init blk_dev_init(void)
 {
+	int i;
+
 	kblockd_workqueue = create_workqueue("kblockd");
 	if (!kblockd_workqueue)
 		panic("Failed to create kblockd\n");
@@ -3352,6 +3448,14 @@ int __init blk_dev_init(void)
 	iocontext_cachep = kmem_cache_create("blkdev_ioc",
 			sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL);
 
+	for (i = 0; i < NR_CPUS; i++)
+		INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
+
+	open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
+#ifdef CONFIG_HOTPLUG_CPU
+	register_cpu_notifier(&blk_cpu_notifier);
+#endif
+
 	blk_max_low_pfn = max_low_pfn;
 	blk_max_pfn = max_pfn;
 

drivers/block/cciss.c

@@ -2178,16 +2178,48 @@ static inline void resend_cciss_cmd( ctlr_info_t *h, CommandList_struct *c)
 
 	start_io(h);
 }
+
+static void cciss_softirq_done(struct request *rq)
+{
+	CommandList_struct *cmd = rq->completion_data;
+	ctlr_info_t *h = hba[cmd->ctlr];
+	u64bit temp64;
+	int i, ddir;
+
+	if (cmd->Request.Type.Direction == XFER_READ)
+		ddir = PCI_DMA_FROMDEVICE;
+	else
+		ddir = PCI_DMA_TODEVICE;
+
+	/* command did not need to be retried */
+	/* unmap the DMA mapping for all the scatter gather elements */
+	for(i=0; i<cmd->Header.SGList; i++) {
+		temp64.val32.lower = cmd->SG[i].Addr.lower;
+		temp64.val32.upper = cmd->SG[i].Addr.upper;
+		pci_unmap_page(h->pdev, temp64.val, cmd->SG[i].Len, ddir);
+	}
+
+	complete_buffers(rq->bio, rq->errors);
+
+#ifdef CCISS_DEBUG
+	printk("Done with %p\n", rq);
+#endif /* CCISS_DEBUG */ 
+
+	spin_lock_irq(&h->lock);
+	end_that_request_last(rq, rq->errors);
+	cmd_free(h, cmd,1);
+	spin_unlock_irq(&h->lock);
+}
+
 /* checks the status of the job and calls complete buffers to mark all 
- * buffers for the completed job. 
+ * buffers for the completed job. Note that this function does not need
+ * to hold the hba/queue lock.
  */ 
 static inline void complete_command( ctlr_info_t *h, CommandList_struct *cmd,
 		int timeout)
 {
 	int status = 1;
-	int i;
 	int retry_cmd = 0;
-	u64bit temp64;
 
 	if (timeout)
 		status = 0; 
@@ -2295,24 +2327,10 @@ static inline void complete_command( ctlr_info_t *h, CommandList_struct *cmd,
 		resend_cciss_cmd(h,cmd);
 		return;
 	}	
-	/* command did not need to be retried */
-	/* unmap the DMA mapping for all the scatter gather elements */
-	for(i=0; i<cmd->Header.SGList; i++) {
-		temp64.val32.lower = cmd->SG[i].Addr.lower;
-		temp64.val32.upper = cmd->SG[i].Addr.upper;
-		pci_unmap_page(hba[cmd->ctlr]->pdev,
-			temp64.val, cmd->SG[i].Len,
-			(cmd->Request.Type.Direction == XFER_READ) ?
-				PCI_DMA_FROMDEVICE : PCI_DMA_TODEVICE);
-	}
-	complete_buffers(cmd->rq->bio, status);
-
-#ifdef CCISS_DEBUG
-	printk("Done with %p\n", cmd->rq);
-#endif /* CCISS_DEBUG */ 
 
-	end_that_request_last(cmd->rq, status ? 1 : -EIO);
-	cmd_free(h,cmd,1);
+	cmd->rq->completion_data = cmd;
+	cmd->rq->errors = status;
+	blk_complete_request(cmd->rq);
 }
 
 /* 
@@ -3199,15 +3217,17 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
 		drv->queue = q;
 
 		q->backing_dev_info.ra_pages = READ_AHEAD;
-	blk_queue_bounce_limit(q, hba[i]->pdev->dma_mask);
+		blk_queue_bounce_limit(q, hba[i]->pdev->dma_mask);
+
+		/* This is a hardware imposed limit. */
+		blk_queue_max_hw_segments(q, MAXSGENTRIES);
 
-	/* This is a hardware imposed limit. */
-	blk_queue_max_hw_segments(q, MAXSGENTRIES);
+		/* This is a limit in the driver and could be eliminated. */
+		blk_queue_max_phys_segments(q, MAXSGENTRIES);
 
-	/* This is a limit in the driver and could be eliminated. */
-	blk_queue_max_phys_segments(q, MAXSGENTRIES);
+		blk_queue_max_sectors(q, 512);
 
-	blk_queue_max_sectors(q, 512);
+		blk_queue_softirq_done(q, cciss_softirq_done);
 
 		q->queuedata = hba[i];
 		sprintf(disk->disk_name, "cciss/c%dd%d", i, j);

drivers/ide/ide-io.c

@@ -55,9 +55,22 @@
 #include <asm/io.h>
 #include <asm/bitops.h>
 
+void ide_softirq_done(struct request *rq)
+{
+	request_queue_t *q = rq->q;
+
+	add_disk_randomness(rq->rq_disk);
+	end_that_request_chunk(rq, rq->errors, rq->data_len);
+
+	spin_lock_irq(q->queue_lock);
+	end_that_request_last(rq, rq->errors);
+	spin_unlock_irq(q->queue_lock);
+}
+
 int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate,
 		      int nr_sectors)
 {
+	unsigned int nbytes;
 	int ret = 1;
 
 	BUG_ON(!(rq->flags & REQ_STARTED));
@@ -81,17 +94,28 @@ int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate,
 		HWGROUP(drive)->hwif->ide_dma_on(drive);
 	}
 
-	if (!end_that_request_first(rq, uptodate, nr_sectors)) {
-		add_disk_randomness(rq->rq_disk);
-
-		if (blk_rq_tagged(rq))
-			blk_queue_end_tag(drive->queue, rq);
-
+	/*
+	 * For partial completions (or non fs/pc requests), use the regular
+	 * direct completion path.
+	 */
+	nbytes = nr_sectors << 9;
+	if (rq_all_done(rq, nbytes)) {
+		rq->errors = uptodate;
+		rq->data_len = nbytes;
 		blkdev_dequeue_request(rq);
 		HWGROUP(drive)->rq = NULL;
-		end_that_request_last(rq, uptodate);
+		blk_complete_request(rq);
 		ret = 0;
+	} else {
+		if (!end_that_request_first(rq, uptodate, nr_sectors)) {
+			add_disk_randomness(rq->rq_disk);
+			blkdev_dequeue_request(rq);
+			HWGROUP(drive)->rq = NULL;
+			end_that_request_last(rq, uptodate);
+			ret = 0;
+		}
 	}
+
 	return ret;
 }
 EXPORT_SYMBOL(__ide_end_request);
@@ -113,6 +137,10 @@ int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
 	unsigned long flags;
 	int ret = 1;
 
+	/*
+	 * room for locking improvements here, the calls below don't
+	 * need the queue lock held at all
+	 */
 	spin_lock_irqsave(&ide_lock, flags);
 	rq = HWGROUP(drive)->rq;
 

drivers/ide/ide-probe.c

@@ -1011,6 +1011,8 @@ static int ide_init_queue(ide_drive_t *drive)
 	blk_queue_max_hw_segments(q, max_sg_entries);
 	blk_queue_max_phys_segments(q, max_sg_entries);
 
+	blk_queue_softirq_done(q, ide_softirq_done);
+
 	/* assign drive queue */
 	drive->queue = q;