Re: [PATCH v7 23/50] powerpc/powernv: Use PE instead of number during setup and release

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On 11/17/2015 08:03 PM, Gavin Shan wrote:

On Tue, Nov 17, 2015 at 04:08:30PM +1100, Alexey Kardashevskiy wrote:

On 11/05/2015 12:12 AM, Gavin Shan wrote:

In current implementation, the PEs that are allocated or picked

>from the reserved list are identified by PE number. The PE instance

has to be picked according to the PE number eventually. We have
same issue when PE is released.

For pnv_ioda_pick_m64_pe() and pnv_ioda_alloc_pe(), this returns
PE instance so that pnv_ioda_setup_bus_PE() can use the allocated
or reserved PE instance directly. Also, pnv_ioda_setup_bus_PE()
returns the reserved/allocated PE instance to be used in subsequent
patches. On the other hand, pnv_ioda_free_pe() uses PE instance
(not number) as its argument. No logical changes introduced.

Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
---
  arch/powerpc/platforms/powernv/pci-ioda.c | 81 +++++++++++++++++--------------
  arch/powerpc/platforms/powernv/pci.h      |  2 +-
  2 files changed, 46 insertions(+), 37 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 488e0f8..ae82df1 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -152,7 +152,7 @@ static void pnv_ioda_reserve_pe(struct pnv_phb *phb, int pe_no)
  	pnv_ioda_init_pe(phb, pe_no);
  }

-static int pnv_ioda_alloc_pe(struct pnv_phb *phb)
+static struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb)
  {
  	unsigned long pe;

@@ -160,19 +160,20 @@ static int pnv_ioda_alloc_pe(struct pnv_phb *phb)
  		pe = find_next_zero_bit(phb->ioda.pe_alloc,
  					phb->ioda.total_pe_num, 0);
  		if (pe >= phb->ioda.total_pe_num)
-			return IODA_INVALID_PE;
+			return NULL;
  	} while(test_and_set_bit(pe, phb->ioda.pe_alloc));

-	pnv_ioda_init_pe(phb, pe);
-	return pe;
+	return pnv_ioda_init_pe(phb, pe);
  }

-static void pnv_ioda_free_pe(struct pnv_phb *phb, int pe)
+static void pnv_ioda_free_pe(struct pnv_ioda_pe *pe)
  {
-	WARN_ON(phb->ioda.pe_array[pe].pdev);
+	struct pnv_phb *phb = pe->phb;
+
+	WARN_ON(pe->pdev);

-	memset(&phb->ioda.pe_array[pe], 0, sizeof(struct pnv_ioda_pe));
-	clear_bit(pe, phb->ioda.pe_alloc);
+	memset(pe, 0, sizeof(struct pnv_ioda_pe));
+	clear_bit(pe->pe_number, phb->ioda.pe_alloc);
  }

  /* The default M64 BAR is shared by all PEs */
@@ -332,7 +333,7 @@ static void pnv_ioda_reserve_m64_pe(struct pci_bus *bus,
  	}
  }

-static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
+static struct pnv_ioda_pe *pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
  {
  	struct pci_controller *hose = pci_bus_to_host(bus);
  	struct pnv_phb *phb = hose->private_data;
@@ -342,7 +343,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)

  	/* Root bus shouldn't use M64 */
  	if (pci_is_root_bus(bus))
-		return IODA_INVALID_PE;
+		return NULL;

  	/* Allocate bitmap */
  	size = _ALIGN_UP(phb->ioda.total_pe_num / 8, sizeof(unsigned long));
@@ -350,7 +351,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
  	if (!pe_alloc) {
  		pr_warn("%s: Out of memory !\n",
  			__func__);
-		return IODA_INVALID_PE;
+		return NULL;
  	}

  	/* Figure out reserved PE numbers by the PE */
@@ -363,7 +364,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
  	 */
  	if (bitmap_empty(pe_alloc, phb->ioda.total_pe_num)) {
  		kfree(pe_alloc);
-		return IODA_INVALID_PE;
+		return NULL;
  	}

  	/*
@@ -409,7 +410,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
  	}

  	kfree(pe_alloc);
-	return master_pe->pe_number;
+	return master_pe;
  }

  static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
@@ -988,28 +989,26 @@ static void pnv_ioda_setup_same_PE(struct pci_bus *bus, struct pnv_ioda_pe *pe)
   * subordinate PCI devices and buses. The second type of PE is normally
   * orgiriated by PCIe-to-PCI bridge or PLX switch downstream ports.
   */
-static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
+static struct pnv_ioda_pe *pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
  {
  	struct pci_controller *hose = pci_bus_to_host(bus);
  	struct pnv_phb *phb = hose->private_data;
-	struct pnv_ioda_pe *pe;
-	int pe_num = IODA_INVALID_PE;
+	struct pnv_ioda_pe *pe = NULL;

  	/* Check if PE is determined by M64 */
  	if (phb->pick_m64_pe)
-		pe_num = phb->pick_m64_pe(bus, all);
+		pe = phb->pick_m64_pe(bus, all);

  	/* The PE number isn't pinned by M64 */
-	if (pe_num == IODA_INVALID_PE)
-		pe_num = pnv_ioda_alloc_pe(phb);
+	if (!pe)
+		pe = pnv_ioda_alloc_pe(phb);

-	if (pe_num == IODA_INVALID_PE) {
+	if (!pe) {
  		pr_warning("%s: Not enough PE# available for PCI bus %04x:%02x\n",
  			__func__, pci_domain_nr(bus), bus->number);
-		return;
+		return NULL;
  	}

-	pe = &phb->ioda.pe_array[pe_num];
  	pe->flags |= (all ? PNV_IODA_PE_BUS_ALL : PNV_IODA_PE_BUS);
  	pe->pbus = bus;
  	pe->pdev = NULL;
@@ -1018,17 +1017,16 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)

  	if (all)
  		pe_info(pe, "Secondary bus %d..%d associated with PE#%d\n",
-			bus->busn_res.start, bus->busn_res.end, pe_num);
+			bus->busn_res.start, bus->busn_res.end, pe->pe_number);
  	else
  		pe_info(pe, "Secondary bus %d associated with PE#%d\n",
-			bus->busn_res.start, pe_num);
+			bus->busn_res.start, pe->pe_number);

  	if (pnv_ioda_configure_pe(phb, pe)) {
  		/* XXX What do we do here ? */
-		if (pe_num)
-			pnv_ioda_free_pe(phb, pe_num);
+		pnv_ioda_free_pe(pe);
  		pe->pbus = NULL;
-		return;
+		return NULL;
  	}

  	/* Associate it with all child devices */
@@ -1036,6 +1034,8 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)

  	/* Put PE to the list */
  	list_add_tail(&pe->list, &phb->ioda.pe_list);
+
+	return pe;
  }

  static void pnv_ioda_setup_PEs(struct pci_bus *bus)
@@ -1267,7 +1267,7 @@ static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)

  		pnv_ioda_deconfigure_pe(phb, pe);

-		pnv_ioda_free_pe(phb, pe->pe_number);
+		pnv_ioda_free_pe(pe);
  	}
  }

@@ -1276,6 +1276,7 @@ void pnv_pci_sriov_disable(struct pci_dev *pdev)
  	struct pci_bus        *bus;
  	struct pci_controller *hose;
  	struct pnv_phb        *phb;
+	struct pnv_ioda_pe    *pe;
  	struct pci_dn         *pdn;
  	struct pci_sriov      *iov;
  	u16                    num_vfs, i;
@@ -1300,8 +1301,11 @@ void pnv_pci_sriov_disable(struct pci_dev *pdev)
  		/* Release PE numbers */
  		if (pdn->m64_single_mode) {
  			for (i = 0; i < num_vfs; i++) {
-				if (pdn->pe_num_map[i] != IODA_INVALID_PE)
-					pnv_ioda_free_pe(phb, pdn->pe_num_map[i]);
+				if (pdn->pe_num_map[i] == IODA_INVALID_PE)
+					continue;
+
+				pe = &phb->ioda.pe_array[pdn->pe_num_map[i]];
+				pnv_ioda_free_pe(pe);
  			}
  		} else
  			bitmap_clear(phb->ioda.pe_alloc, *pdn->pe_num_map, num_vfs);
@@ -1354,9 +1358,8 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)

  		if (pnv_ioda_configure_pe(phb, pe)) {
  			/* XXX What do we do here ? */
-			if (pe_num)
-				pnv_ioda_free_pe(phb, pe_num);
  			pe->pdev = NULL;
+			pnv_ioda_free_pe(pe);




pnv_ioda_free_pe() does WARN_ON(pdev). Before this patch you would free PE
first and then reset pe->pdev, now you reset it first, then call
pnv_ioda_free_pe(). This change is not just about "Use PE instead of number
during setup and release", is/was that a bug?

And I fail to see when pe->pdev could get initialized in
pnv_ioda_configure_pe() as pnv_pci_dma_dev_setup() should not be called while
pnv_ioda_setup_vf_PE() is working.



It wasn't or isn't a bug as
There is an unexplained change in behavior - after the patch pe->pdev gets cleaned before pnv_ioda_free_pe(), before the patch it was opposite. Your options are: - remove "No logical changes introduced" from the commit log and explain the change or 
- move "pe->pdev = NULL;" after pnv_ioda_free_pe().




pe->pdev is initialized in arch/powerpc/platform/powernv/pci.c::
pnv_pci_dma_dev_setup()
So when pnv_ioda_setup_vf_PE() starts working, it is valid for pe->pdev to have not-NULL pointer? Because nothing in pnv_ioda_setup_vf_PE() calls pnv_pci_dma_dev_setup(), explicitly or implicitly. 







  			continue;
  		}

@@ -1374,6 +1377,7 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
  	struct pci_bus        *bus;
  	struct pci_controller *hose;
  	struct pnv_phb        *phb;
+	struct pnv_ioda_pe    *pe;
  	struct pci_dn         *pdn;
  	int                    ret;
  	u16                    i;
@@ -1416,11 +1420,13 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
  		/* Calculate available PE for required VFs */
  		if (pdn->m64_single_mode) {
  			for (i = 0; i < num_vfs; i++) {
-				pdn->pe_num_map[i] = pnv_ioda_alloc_pe(phb);
-				if (pdn->pe_num_map[i] == IODA_INVALID_PE) {
+				pe = pnv_ioda_alloc_pe(phb);
+				if (!pe) {
  					ret = -EBUSY;
  					goto m64_failed;
  				}
+
+				pdn->pe_num_map[i] = pe->pe_number;
  			}
  		} else {
  			mutex_lock(&phb->ioda.pe_alloc_mutex);
@@ -1465,8 +1471,11 @@ int pnv_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
  m64_failed:
  	if (pdn->m64_single_mode) {
  		for (i = 0; i < num_vfs; i++) {
-			if (pdn->pe_num_map[i] != IODA_INVALID_PE)
-				pnv_ioda_free_pe(phb, pdn->pe_num_map[i]);
+			if (pdn->pe_num_map[i] == IODA_INVALID_PE)
+				continue;
+
+			pe = &phb->ioda.pe_array[pdn->pe_num_map[i]];
+			pnv_ioda_free_pe(pe);
  		}
  	} else
  		bitmap_clear(phb->ioda.pe_alloc, *pdn->pe_num_map, num_vfs);
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 5df945f..e55ab0e 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -105,7 +105,7 @@ struct pnv_phb {
  	int (*init_m64)(struct pnv_phb *phb);
  	void (*reserve_m64_pe)(struct pci_bus *bus,
  			       unsigned long *pe_bitmap, bool all);
-	int (*pick_m64_pe)(struct pci_bus *bus, bool all);
+	struct pnv_ioda_pe *(*pick_m64_pe)(struct pci_bus *bus, bool all);
  	int (*get_pe_state)(struct pnv_phb *phb, int pe_no);
  	void (*freeze_pe)(struct pnv_phb *phb, int pe_no);
  	int (*unfreeze_pe)(struct pnv_phb *phb, int pe_no, int opt);



Thanks,
Gavin




--
Alexey
--
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