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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: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Sebastian Ott 2016-09-08 13:44:57 +02:00 committed by Martin Schwidefsky
parent 6b7df3ce92
commit 4f5359e94b
1 changed files with 11 additions and 8 deletions
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19
arch/s390/pci/pci_dma.c
View File

@ -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)))
return 0;
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;