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authorSebastian Ott <sebott@linux.vnet.ibm.com>2016-09-08 14:44:57 +0300
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-11-17 09:10:08 +0300
commit4f5359e94bbfbe349fd1ae00516dfe749d53fe22 (patch)
tree7e3ba089f8df67aa0219c41691939af49975c271 /arch/s390/pci/pci_dma.c
parent6b7df3ce92ac82ec3f4a2953b6fed77da7b38aaa (diff)
downloadlinux-4f5359e94bbfbe349fd1ae00516dfe749d53fe22.tar.xz
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>
Diffstat (limited to 'arch/s390/pci/pci_dma.c')
-rw-r--r--arch/s390/pci/pci_dma.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 47f4afbff0a5..0c626c1303cb 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -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;