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PCI: Fix issue with "pci=disable_acs_redir" parameter being ignored

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[ Upstream commit d5bc73f34c ]

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: d2fd6e8191 ("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>
This commit is contained in:
Logan Gunthorpe 2019-04-10 15:05:31 -06:00 committed by Greg Kroah-Hartman
parent b21ca2769b
commit a469646862
1 changed files with 17 additions and 2 deletions
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19
drivers/pci/pci.c
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@ -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);