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

Gavin Shan
2015-11-22T22:58:17Z

On Wed, Nov 18, 2015 at 11:13:55AM +1100, Alexey Kardashevskiy wrote:
>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@linux.vnet.ibm.com>
>>>>---
>>>> 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().
>

I'll take option#1: to drop this specific change in next revision.

>
>
>>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.
>

Correct.

>
>
>>>
>>>> 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