From: Logan Gunthorpe logang@deltatee.com
[ Upstream commit d5bc73f34cc97c4b4b9202cc93182c2515076edf ]
In most cases, kmalloc() will not be available early in boot when pci_setup() is called. Thus, the kstrdup() call that was added to fix the __initdata bug with the disable_acs_redir parameter usually returns NULL, so the parameter is discarded and has no effect.
To fix this, store the string that's in initdata until an initcall function can allocate the memory appropriately. This way we don't need any additional static memory.
Fixes: d2fd6e81912a ("PCI: Fix __initdata issue with "pci=disable_acs_redir" parameter") Signed-off-by: Logan Gunthorpe logang@deltatee.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/pci.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 30649addc6252..61f2ef28ea1c7 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6135,8 +6135,7 @@ static int __init pci_setup(char *str) } else if (!strncmp(str, "pcie_scan_all", 13)) { pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); } else if (!strncmp(str, "disable_acs_redir=", 18)) { - disable_acs_redir_param = - kstrdup(str + 18, GFP_KERNEL); + disable_acs_redir_param = str + 18; } else { printk(KERN_ERR "PCI: Unknown option `%s'\n", str); @@ -6147,3 +6146,19 @@ static int __init pci_setup(char *str) return 0; } early_param("pci", pci_setup); + +/* + * 'disable_acs_redir_param' is initialized in pci_setup(), above, to point + * to data in the __initdata section which will be freed after the init + * sequence is complete. We can't allocate memory in pci_setup() because some + * architectures do not have any memory allocation service available during + * an early_param() call. So we allocate memory and copy the variable here + * before the init section is freed. + */ +static int __init pci_realloc_setup_params(void) +{ + disable_acs_redir_param = kstrdup(disable_acs_redir_param, GFP_KERNEL); + + return 0; +} +pure_initcall(pci_realloc_setup_params);