Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc update from Benjamin Herrenschmidt:
 "The main highlights this time around are:

   - A pile of addition POWER8 bits and nits, such as updated
     performance counter support (Michael Ellerman), new branch history
     buffer support (Anshuman Khandual), base support for the new PCI
     host bridge when not using the hypervisor (Gavin Shan) and other
     random related bits and fixes from various contributors.

   - Some rework of our page table format by Aneesh Kumar which fixes a
     thing or two and paves the way for THP support.  THP itself will
     not make it this time around however.

   - More Freescale updates, including Altivec support on the new e6500
     cores, new PCI controller support, and a pile of new boards support
     and updates.

   - The usual batch of trivial cleanups & fixes"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (156 commits)
  powerpc: Fix build error for book3e
  powerpc: Context switch the new EBB SPRs
  powerpc: Turn on the EBB H/FSCR bits
  powerpc: Replace CPU_FTR_BCTAR with CPU_FTR_ARCH_207S
  powerpc: Setup BHRB instructions facility in HFSCR for POWER8
  powerpc: Fix interrupt range check on debug exception
  powerpc: Update tlbie/tlbiel as per ISA doc
  powerpc: Print page size info during boot
  powerpc: print both base and actual page size on hash failure
  powerpc: Fix hpte_decode to use the correct decoding for page sizes
  powerpc: Decode the pte-lp-encoding bits correctly.
  powerpc: Use encode avpn where we need only avpn values
  powerpc: Reduce PTE table memory wastage
  powerpc: Move the pte free routines from common header
  powerpc: Reduce the PTE_INDEX_SIZE
  powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format
  powerpc: New hugepage directory format
  powerpc: Don't truncate pgd_index wrongly
  powerpc: Don't hard code the size of pte page
  powerpc: Save DAR and DSISR in pt_regs on MCE
  ...

1 files changed, 26 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 1b2a174..86ae364 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -924,6 +924,13 @@ static void restore_default_window(struct pci_dev *dev,
 	__restore_default_window(pci_dev_to_eeh_dev(dev), ddw_restore_token);
 }
 
+struct failed_ddw_pdn {
+	struct device_node *pdn;
+	struct list_head list;
+};
+
+static LIST_HEAD(failed_ddw_pdn_list);
+
 /*
  * If the PE supports dynamic dma windows, and there is space for a table
  * that can map all pages in a linear offset, then setup such a table,
@@ -951,6 +958,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 	struct dynamic_dma_window_prop *ddwprop;
 	const void *dma_window = NULL;
 	unsigned long liobn, offset, size;
+	struct failed_ddw_pdn *fpdn;
 
 	mutex_lock(&direct_window_init_mutex);
 
@@ -959,6 +967,18 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 		goto out_unlock;
 
 	/*
+	 * If we already went through this for a previous function of
+	 * the same device and failed, we don't want to muck with the
+	 * DMA window again, as it will race with in-flight operations
+	 * and can lead to EEHs. The above mutex protects access to the
+	 * list.
+	 */
+	list_for_each_entry(fpdn, &failed_ddw_pdn_list, list) {
+		if (!strcmp(fpdn->pdn->full_name, pdn->full_name))
+			goto out_unlock;
+	}
+
+	/*
 	 * the ibm,ddw-applicable property holds the tokens for:
 	 * ibm,query-pe-dma-window
 	 * ibm,create-pe-dma-window
@@ -1114,6 +1134,12 @@ out_restore_window:
 	if (ddw_restore_token)
 		restore_default_window(dev, ddw_restore_token);
 
+	fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL);
+	if (!fpdn)
+		goto out_unlock;
+	fpdn->pdn = pdn;
+	list_add(&fpdn->list, &failed_ddw_pdn_list);
+
 out_unlock:
 	mutex_unlock(&direct_window_init_mutex);
 	return dma_addr;