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Commit 70aaf61a authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Bjorn Helgaas
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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: default avatarLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 8050f3f6

drivers/pci/pci.c

+23 −18
Original line number Diff line number Diff line
@@ -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);

	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;