From: Wade Mealing <wmealing@redhat.com>
Date: Mon, 26 Jul 2010 07:42:49 -0400
Subject: [pci] fix remove of proc entry for hotplug devices
Message-id: <1280130169-10728-1-git-send-email-wmealing@redhat.com>
Patchwork-id: 27088
O-Subject: [PATCH] [RHEL 5.5] BZ 618114 - remove proc entry for hotplug devices,
	ignoring use count.
Bugzilla: 618114
RH-Acked-by: Dean Nelson <dnelson@redhat.com>
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>
RH-Acked-by: Don Zickus <dzickus@redhat.com>

The /proc/bus/pci/xx/yy is not removed when the device is hot removed
if the file is open.  Reading the file after the device is removed
causes a kernel panic.

Because the pci_proc_detach_device() doesn't call remove_proc_entry()
if struct proc_dir_entry->count > 1, access to /proc/bus/pci/XX/YY
would refer to struct pci_dev that was already freed.

Though I don't know why the check for proc_dir_entry->count was added,
I don't think it is needed. Removing this check fixes the problem.

This is a backport of the patch from https://patchwork.kernel.org/patch/107556/
which has been accepted and applied to the linux-next tree.

diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index 99cf333..d515093 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -417,8 +417,6 @@ int pci_proc_detach_device(struct pci_dev *dev)
 	struct proc_dir_entry *e;
 
 	if ((e = dev->procent)) {
-		if (atomic_read(&e->count))
-			return -EBUSY;
 		remove_proc_entry(e->name, dev->bus->procdir);
 		dev->procent = NULL;
 	}