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Commit 4f5359e9 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
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s390/pci_dma: make lazy flush independent from the tlb_refresh bit 



We have 2 strategies to reduce the number of RPCIT instructions:
* A HW feature indicated via the tlb_refresh bit allows us to omit RPCIT for
  invalid -> valid translation-table entry updates.
* With "lazy flush" we omit RPCIT for valid -> invalid updates until we run
  out of dma addresses. When we have to reuse dma addresses we issue a global
  tlb flush using only one RPCIT instruction.

Currently lazy flushing depends on tlb_refresh. Since there is no technical
reason for this remove this dependency.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 6b7df3ce

arch/s390/pci/pci_dma.c

+11 −8
Original line number Diff line number Diff line
@@ -181,14 +181,17 @@ static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr, 
	/*

	 * With zdev->tlb_refresh == 0, rpcit is not required to establish new

	 * translations when previously invalid translation-table entries are

	 * validated. With lazy unmap, it also is skipped for previously valid

	 * validated. With lazy unmap, rpcit is skipped for previously valid

	 * entries, but a global rpcit is then required before any address can

	 * be re-used, i.e. after each iommu bitmap wrap-around.

	 */

	if (!zdev->tlb_refresh &&

			(!s390_iommu_strict ||

			((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))

	if ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID) {

		if (!zdev->tlb_refresh)

			return 0;

	} else {

		if (!s390_iommu_strict)

			return 0;

	}



	return zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,

				  PAGE_ALIGN(size));
@@ -257,7 +260,7 @@ static dma_addr_t dma_alloc_address(struct device *dev, int size) 
	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);

	offset = __dma_alloc_iommu(dev, zdev->next_bit, size);

	if (offset == -1) {

		if (!zdev->tlb_refresh && !s390_iommu_strict) {

		if (!s390_iommu_strict) {

			/* global flush before DMA addresses are reused */

			if (zpci_refresh_global(zdev))

				goto out_error;
@@ -292,7 +295,7 @@ static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size) 
	if (!zdev->iommu_bitmap)

		goto out;



	if (zdev->tlb_refresh || s390_iommu_strict)

	if (s390_iommu_strict)

		bitmap_clear(zdev->iommu_bitmap, offset, size);

	else

		bitmap_set(zdev->lazy_bitmap, offset, size);
@@ -565,7 +568,7 @@ int zpci_dma_init_device(struct zpci_dev *zdev) 
		rc = -ENOMEM;

		goto free_dma_table;

	}

	if (!zdev->tlb_refresh && !s390_iommu_strict) {

	if (!s390_iommu_strict) {

		zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);

		if (!zdev->lazy_bitmap) {

			rc = -ENOMEM;