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SubjectRe: [PATCH] Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"
Date
On Friday, January 31, 2014 05:56:30 PM Yinghai Lu wrote:
> On Fri, Jan 31, 2014 at 3:34 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

[...]

> > diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
> > index 4ff36bfa785e..b8c93c90daf5 100644
> > --- a/drivers/pci/remove.c
> > +++ b/drivers/pci/remove.c
> > @@ -3,6 +3,20 @@
> > #include <linux/pci-aspm.h>
> > #include "pci.h"
> >
> > +static void pci_free_resources(struct pci_dev *dev)
> > +{
> > + int i;
> > +
> > + msi_remove_pci_irq_vectors(dev);
>
> looks like you are in a rush. Why do you put back msi_remove_pci_irq_vectors?

I simply did "git revert" and that's the result.

Sorry about overlooking that, but your commit's changelog didn't mention
removing it either.

Updated revert follows.

Thanks,
Rafael


---
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"

Revert commit ef83b0781a73 "PCI: Remove from bus_list and release
resources in pci_release_dev()" that made some nasty race conditions
become possible. For example, if a Thunderbolt link is unplugged
and then replugged immediately, the pci_release_dev() resulting from
the hot-remove code path may be racing with the hot-add code path
which after that commit causes various kinds of breakage to happen
(up to and including a hard crash of the whole system).

Moreover, the problem that commit ef83b0781a73 attempted to address
cannot happen any more after commit 8a4c5c329de7 "PCI: Check parent
kobject in pci_destroy_dev()", because pci_destroy_dev() will now
return immediately if it has already been executed for the given
device.

Note, however, that the invocation of msi_remove_pci_irq_vectors()
removed by commit ef83b0781a73 from pci_free_resources() along with
the other changes made by it is not added back because of subsequent
code changes depending on that modification.

Fixes: ef83b0781a73 (PCI: Remove from bus_list and release resources in pci_release_dev())
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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---
drivers/pci/probe.c | 21 ++-------------------
drivers/pci/remove.c | 17 +++++++++++++++++
2 files changed, 19 insertions(+), 19 deletions(-)

Index: linux-pm/drivers/pci/probe.c
===================================================================
--- linux-pm.orig/drivers/pci/probe.c
+++ linux-pm/drivers/pci/probe.c
@@ -1208,18 +1208,6 @@ static void pci_release_capabilities(str
pci_free_cap_save_buffers(dev);
}

-static void pci_free_resources(struct pci_dev *dev)
-{
- int i;
-
- pci_cleanup_rom(dev);
- for (i = 0; i < PCI_NUM_RESOURCES; i++) {
- struct resource *res = dev->resource + i;
- if (res->parent)
- release_resource(res);
- }
-}
-
/**
* pci_release_dev - free a pci device structure when all users of it are finished.
* @dev: device that's been disconnected
@@ -1229,14 +1217,9 @@ static void pci_free_resources(struct pc
*/
static void pci_release_dev(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
-
- down_write(&pci_bus_sem);
- list_del(&pci_dev->bus_list);
- up_write(&pci_bus_sem);
-
- pci_free_resources(pci_dev);
+ struct pci_dev *pci_dev;

+ pci_dev = to_pci_dev(dev);
pci_release_capabilities(pci_dev);
pci_release_of_node(pci_dev);
pcibios_release_device(pci_dev);
Index: linux-pm/drivers/pci/remove.c
===================================================================
--- linux-pm.orig/drivers/pci/remove.c
+++ linux-pm/drivers/pci/remove.c
@@ -3,6 +3,18 @@
#include <linux/pci-aspm.h>
#include "pci.h"

+static void pci_free_resources(struct pci_dev *dev)
+{
+ int i;
+
+ pci_cleanup_rom(dev);
+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+ struct resource *res = dev->resource + i;
+ if (res->parent)
+ release_resource(res);
+ }
+}
+
static void pci_stop_dev(struct pci_dev *dev)
{
pci_pme_active(dev, false);
@@ -25,6 +37,11 @@ static void pci_destroy_dev(struct pci_d

device_del(&dev->dev);

+ down_write(&pci_bus_sem);
+ list_del(&dev->bus_list);
+ up_write(&pci_bus_sem);
+
+ pci_free_resources(dev);
put_device(&dev->dev);
}



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