On 2013/1/25 6:45, Bjorn Helgaas wrote:
Hi Bjorn,
Thanks for your review and great work for this series patches!
>
> I applied this series on the pci/yijing-ari branch in my git tree,
> with the following changes:
>
> - Updated changelogs for readability
> - Reworked next_fn() and made it static
> - Updated the unconfigure/disable paths for cpcihp, sgihp, shpchp
> - Check PCI_SLOT for non-PCIe drivers in case a bus has several slots
> - Reset "Author:" to Yijing (since you wrote the original patches)
>
> Please review the changes I made and test the parts you can. I need
> your acknowledgement before putting these in "next" with your
> Signed-off-by because I changed them so much.
I reviewed the changes and tested this series again in my hotplug machine.
Most of the changes looks good to me except [PATCH 3/7] PCI: Consolidate "next-function" functions.
Currently, if parameter "dev" is passed as NULL (pci_scan_single_device() return NULL), next_fn
will return 0, so pci_scan_slot() will stop scanning rest function devices in this slot.
According to PCI 3.0 Spec "Multi-function devices require to always implement function 0
in the device. Implementing other functions is optional and maybe assigned in any order".
So we will miss some function devices when scanning pci slot. I tested this patch in my machine and found it boot failed,
because some usb devices can not found.
+static unsigned next_fn(struct pci_bus *bus, struct pci_dev *dev, unsigned fn)
{
- u16 cap;
- unsigned pos, next_fn;
+ int pos;
+ u16 cap = 0;
+ unsigned next_fn;
if (!dev)
return 0;
lspci info:
00:16.0 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.1 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.2 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.3 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.4 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.5 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.6 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:16.7 System peripheral: Intel Corporation 5520/5500/X58 Chipset QuickData Technology Device (rev 22)
00:1a.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #4
00:1a.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #5
00:1a.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #6
00:1a.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #2
I fixed this problem with [PATCH 3/7] PCI: Consolidate "next-function" functions.
And attach this refreshed patch at the end. This patch has been tested, and result is ok in my machine.
>
> I think there are really two defects you're fixing here:
>
> (1) If you hot-remove an ARI device and replace it with a non-ARI
> multi-function device, we find only function 0 of the new device
> because the upstream bridge still has ARI enabled, and next_ari_fn()
> only returns function 0 for non-ARI devices. Patch [1/7] fixes this.
> I think this is the issue shown by your dmesg quotes above.
>
> (2) If you hot-add an ARI device, the PCI core enumerates all the
> functions, but pciehp only initializes functions 0-7, and other
> functions don't work correctly. Additionally, if you hot-remove the
> device, pciehp only removes functions 0-7, leaving stale pci_dev
> structures around. Patch [4/7] fixes this.
>
> If my understanding is correct, I'll update the commit logs to mention
> these scenarios explicitly.
Yes, exactly.
Thanks!
Yijing.
>
> Bjorn
>
> .
>
--
Thanks!
Yijing
>From 440b930c73d41328c2e355ce989d0e26ee69a50e Mon Sep 17 00:00:00 2001
From: Yijing Wang <wangyijing@xxxxxxxxxx>
Date: Tue, 15 Jan 2013 11:12:18 +0800
Subject: [PATCH] PCI: Consolidate "next-function" functions
There are several next_fn functions (no_next_fn, next_trad_fn,
next_ari_fn); consolidate them in next_fn() to simplify the code.
[bhelgaas: rework code, make next_fn() static, remove NULL checks]
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/probe.c | 47 ++++++++++++++++++++---------------------------
1 files changed, 20 insertions(+), 27 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 7b9e691..75721a2 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1349,31 +1349,30 @@ struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn)
}
EXPORT_SYMBOL(pci_scan_single_device);
-static unsigned next_ari_fn(struct pci_dev *dev, unsigned fn)
+static unsigned next_fn(struct pci_bus *bus, struct pci_dev *dev, unsigned fn)
{
- u16 cap;
- unsigned pos, next_fn;
+ int pos;
+ u16 cap = 0;
+ unsigned next_fn;
- if (!dev)
- return 0;
+ if (pci_ari_enabled(bus)) {
+ if (!dev)
+ return 0;
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
+ if (!pos)
+ return 0;
- pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
- if (!pos)
- return 0;
- pci_read_config_word(dev, pos + 4, &cap);
- next_fn = cap >> 8;
- if (next_fn <= fn)
- return 0;
- return next_fn;
-}
+ pci_read_config_word(dev, pos + PCI_ARI_CAP, &cap);
+ next_fn = PCI_ARI_CAP_NFN(cap);
+ if (next_fn <= fn)
+ return 0; /* protect against malformed list */
-static unsigned next_trad_fn(struct pci_dev *dev, unsigned fn)
-{
- return (fn + 1) % 8;
-}
+ return next_fn;
+ }
-static unsigned no_next_fn(struct pci_dev *dev, unsigned fn)
-{
+ if (!dev || dev->multifunction)
+ return (fn + 1) % 8;
+
return 0;
}
@@ -1406,7 +1405,6 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
{
unsigned fn, nr = 0;
struct pci_dev *dev;
- unsigned (*next_fn)(struct pci_dev *, unsigned) = no_next_fn;
if (only_one_child(bus) && (devfn > 0))
return 0; /* Already scanned the entire slot */
@@ -1417,12 +1415,7 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
if (!dev->is_added)
nr++;
- if (pci_ari_enabled(bus))
- next_fn = next_ari_fn;
- else if (dev->multifunction)
- next_fn = next_trad_fn;
-
- for (fn = next_fn(dev, 0); fn > 0; fn = next_fn(dev, fn)) {
+ for (fn = next_fn(bus, dev, 0); fn > 0; fn = next_fn(bus, dev, fn)) {
dev = pci_scan_single_device(bus, devfn + fn);
if (dev) {
if (!dev->is_added)
--
1.7.1
