patch pci-repair-pci_save-restore_state-so-we-can-restore-one-save-many-times.patch added to gregkh-2.6 tree

gregkh
2007-03-10T07:52:12Z

This is a note to let you know that I've just added the patch titled

Subject: pci: Repair pci_save/restore_state so we can restore one save many times.

to my gregkh-2.6 tree. Its filename is

pci-repair-pci_save-restore_state-so-we-can-restore-one-save-many-times.patch

This tree can be found at
http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/

>From owner-linux-pci@atrey.karlin.mff.cuni.cz Thu Mar 8 12:06:39 2007
From: Eric W. Biederman <ebiederm@xmission.com>
Date: Thu, 08 Mar 2007 13:06:13 -0700
Subject: pci: Repair pci_save/restore_state so we can restore one save many times.
To: Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jeff Garzik <jeff@garzik.org>, "Kok, Auke" <auke-jan.h.kok@intel.com>, Ingo Molnar <mingo@elte.hu>, "Michael S. Tsirkin" <mst@mellanox.co.il>, Pavel Machek <pavel@ucw.cz>, Jens Axboe <jens.axboe@oracle.com>, Adrian Bunk <bunk@stusta.de>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>, linux-pm@lists.osdl.org, Michal Piotrowski <michal.k.k.piotrowski@gmail.com>, Greg Kroah-Hartman <gregkh@suse.de>, <linux-pci@atrey.karlin.mff.cuni.cz>, michael@ellerman.id.au
Message-ID: <m1lki75wlm.fsf_-_@ebiederm.dsl.xmission.com>

From: Eric W. Biederman <ebiederm@xmission.com>

Because we do not reserve space for the pci-x and pci-e state in struct
pci dev we need to dynamically allocate it. However because we need
to support restore being called multiple times after a single save
it is never safe to free the buffers we have allocated to hold the
state.

So this patch modifies the save routines to first check to see
if we have already allocated a state buffer before allocating
a new one. Then the restore routines are modified to not free
the state after restoring it. Simple and it fixes some subtle
error path handling bugs, that are hard to test for.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/pci/pci.c | 12 ++++++------
include/linux/pci.h | 5 -----
2 files changed, 6 insertions(+), 11 deletions(-)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -551,7 +551,9 @@ static int pci_save_pcie_state(struct pc
if (pos <= 0)
return 0;

- save_state = kzalloc(sizeof(*save_state) + sizeof(u16) * 4, GFP_KERNEL);
+ save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
+ if (!save_state)
+ save_state = kzalloc(sizeof(*save_state) + sizeof(u16) * 4, GFP_KERNEL);
if (!save_state) {
dev_err(&dev->dev, "Out of memory in pci_save_pcie_state\n");
return -ENOMEM;
@@ -582,8 +584,6 @@ static void pci_restore_pcie_state(struc
pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
- pci_remove_saved_cap(save_state);
- kfree(save_state);
}

@@ -597,7 +597,9 @@ static int pci_save_pcix_state(struct pc
if (pos <= 0)
return 0;

- save_state = kzalloc(sizeof(*save_state) + sizeof(u16), GFP_KERNEL);
+ save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
+ if (!save_state)
+ save_state = kzalloc(sizeof(*save_state) + sizeof(u16), GFP_KERNEL);
if (!save_state) {
dev_err(&dev->dev, "Out of memory in pci_save_pcie_state\n");
return -ENOMEM;
@@ -622,8 +624,6 @@ static void pci_restore_pcix_state(struc
cap = (u16 *)&save_state->data[0];

pci_write_config_word(dev, pos + PCI_X_CMD, cap[i++]);
- pci_remove_saved_cap(save_state);
- kfree(save_state);
}

--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -222,11 +222,6 @@ static inline void pci_add_saved_cap(str
hlist_add_head(&new_cap->next, &pci_dev->saved_cap_space);
}

-static inline void pci_remove_saved_cap(struct pci_cap_saved_state *cap)
-{
- hlist_del(&cap->next);
-}
-
/*
* For PCI devices, the region numbers are assigned this way:
*

Patches currently in gregkh-2.6 which might be from ebiederm@xmission.com are