[PATCH] pci: Repair pci_save/restore_state so we can restore one save many times.

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>
Acked-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6048c0c637a0eaeae18e23461389d7c45e41759f..d3eab057b2d36fb9d3a8db55194ff3a0972ba212 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -551,7 +551,9 @@ static int pci_save_pcie_state(struct pci_dev *dev)
        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(struct pci_dev *dev)
        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 pci_dev *dev)
        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(struct pci_dev *dev)
        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);
 }
 
 

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 78417e421b4c2d942c0ce7038e22a677bf220742..481ea0663f19f18c9d6e35202d9b64b14398f182 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -209,11 +209,6 @@ static inline void pci_add_saved_cap(struct pci_dev *pci_dev,
        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:
  *