releases/5.0.19/pci-fix-issue-with-pci-disable_acs_redir-parameter-b.patch

   1 From 61b682be17b429c09e24c50bcf4429bd352275d8 Mon Sep 17 00:00:00 2001
   2 From: Logan Gunthorpe <logang@deltatee.com>
   3 Date: Wed, 10 Apr 2019 15:05:31 -0600
   4 Subject: PCI: Fix issue with "pci=disable_acs_redir" parameter being ignored
   5
   6 [ Upstream commit d5bc73f34cc97c4b4b9202cc93182c2515076edf ]
   7
   8 In most cases, kmalloc() will not be available early in boot when
   9 pci_setup() is called.  Thus, the kstrdup() call that was added to fix the
  10 __initdata bug with the disable_acs_redir parameter usually returns NULL,
  11 so the parameter is discarded and has no effect.
  12
  13 To fix this, store the string that's in initdata until an initcall function
  14 can allocate the memory appropriately.  This way we don't need any
  15 additional static memory.
  16
  17 Fixes: d2fd6e81912a ("PCI: Fix __initdata issue with "pci=disable_acs_redir" parameter")
  18 Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
  19 Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
  20 Signed-off-by: Sasha Levin <sashal@kernel.org>
  21 ---
  22  drivers/pci/pci.c | 19 +++++++++++++++++--
  23  1 file changed, 17 insertions(+), 2 deletions(-)
  24
  25 diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
  26 index e91005d0f20c7..3f77bab698ced 100644
  27 --- a/drivers/pci/pci.c
  28 +++ b/drivers/pci/pci.c
  29 @@ -6266,8 +6266,7 @@ static int __init pci_setup(char *str)
  30                         } else if (!strncmp(str, "pcie_scan_all", 13)) {
  31                                 pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
  32                         } else if (!strncmp(str, "disable_acs_redir=", 18)) {
  33 -                               disable_acs_redir_param =
  34 -                                       kstrdup(str + 18, GFP_KERNEL);
  35 +                               disable_acs_redir_param = str + 18;
  36                         } else {
  37                                 printk(KERN_ERR "PCI: Unknown option `%s'\n",
  38                                                 str);
  39 @@ -6278,3 +6277,19 @@ static int __init pci_setup(char *str)
  40         return 0;
  41  }
  42  early_param("pci", pci_setup);
  43 +
  44 +/*
  45 + * 'disable_acs_redir_param' is initialized in pci_setup(), above, to point
  46 + * to data in the __initdata section which will be freed after the init
  47 + * sequence is complete. We can't allocate memory in pci_setup() because some
  48 + * architectures do not have any memory allocation service available during
  49 + * an early_param() call. So we allocate memory and copy the variable here
  50 + * before the init section is freed.
  51 + */
  52 +static int __init pci_realloc_setup_params(void)
  53 +{
  54 +       disable_acs_redir_param = kstrdup(disable_acs_redir_param, GFP_KERNEL);
  55 +
  56 +       return 0;
  57 +}
  58 +pure_initcall(pci_realloc_setup_params);
  59 --
  60 2.20.1
  61