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PCI: Clean up resource_alignment parameter to not require static buffer 

Clean up the 'resource_alignment' parameter code to use kstrdup() in the
initcall routine instead of a static buffer that wastes memory regardless
of whether the feature is used.  This allows us to drop 'COMMAND_LINE_SIZE'
bytes (typically 256-4096 depending on architecture) of static data.

This is similar to what has been done for the 'disable_acs_redir'
parameter.

Link: https://lore.kernel.org/r/20190822161013.5481-2-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Logan Gunthorpe 2019-08-22 10:10:11 -06:00 committed by Bjorn Helgaas
parent 8050f3f664
commit 70aaf61a9b
1 changed files with 23 additions and 18 deletions
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41
drivers/pci/pci.c
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@ -5932,8 +5932,7 @@ resource_size_t __weak pcibios_default_alignment(void)
return 0;
}
#define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE
static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0};
static char *resource_alignment_param;
static DEFINE_SPINLOCK(resource_alignment_lock);
/**
@ -5954,7 +5953,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
spin_lock(&resource_alignment_lock);
p = resource_alignment_param;
if (!*p && !align)
if (!p || !*p)
goto out;
if (pci_has_flag(PCI_PROBE_ONLY)) {
align = 0;
@ -6120,21 +6119,25 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
static ssize_t pci_set_resource_alignment_param(const char *buf, size_t count)
{
if (count > RESOURCE_ALIGNMENT_PARAM_SIZE - 1)
count = RESOURCE_ALIGNMENT_PARAM_SIZE - 1;
spin_lock(&resource_alignment_lock);
strncpy(resource_alignment_param, buf, count);
resource_alignment_param[count] = '\0';
kfree(resource_alignment_param);
resource_alignment_param = kstrndup(buf, count, GFP_KERNEL);
spin_unlock(&resource_alignment_lock);
return count;
return resource_alignment_param ? count : -ENOMEM;
}
static ssize_t pci_get_resource_alignment_param(char *buf, size_t size)
{
size_t count;
size_t count = 0;
spin_lock(&resource_alignment_lock);
count = snprintf(buf, size, "%s", resource_alignment_param);
if (resource_alignment_param)
count = snprintf(buf, size, "%s", resource_alignment_param);
spin_unlock(&resource_alignment_lock);
return count;
}
@ -6275,8 +6278,7 @@ static int __init pci_setup(char *str)
} else if (!strncmp(str, "cbmemsize=", 10)) {
pci_cardbus_mem_size = memparse(str + 10, &str);
} else if (!strncmp(str, "resource_alignment=", 19)) {
pci_set_resource_alignment_param(str + 19,
strlen(str + 19));
resource_alignment_param = str + 19;
} else if (!strncmp(str, "ecrc=", 5)) {
pcie_ecrc_get_policy(str + 5);
} else if (!strncmp(str, "hpiosize=", 9)) {
@ -6311,15 +6313,18 @@ static int __init pci_setup(char *str)
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.
* 'resource_alignment_param' and 'disable_acs_redir_param' are 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)
{
resource_alignment_param = kstrdup(resource_alignment_param,
GFP_KERNEL);
disable_acs_redir_param = kstrdup(disable_acs_redir_param, GFP_KERNEL);
return 0;