Unverified Commit d47bde70 authored by Philipp Stanner's avatar Philipp Stanner Committed by Krzysztof Wilczyński
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PCI: Add managed pcim_request_region() 

These existing functions:

  pci_request_region()
  pci_request_selected_regions()
  pci_request_selected_regions_exclusive()

are "hybrid" functions built on __pci_request_region() and are managed if
pcim_enable_device() has been called, but unmanaged otherwise.

Add these new functions:

  pcim_request_region()
  pcim_request_region_exclusive()

These are *always* managed and use the new pcim_addr_devres tracking
infrastructure instead of find_pci_dr() and struct pci_devres.region_mask.

Implement the hybrid functions using the new "pure" functions and remove
struct pci_devres.region_mask, which is no longer needed.

Link: https://lore.kernel.org/r/20240613115032.29098-6-pstanner@redhat.com


Signed-off-by: default avatarPhilipp Stanner <pstanner@redhat.com>
Signed-off-by: default avatarKrzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: commit log]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent e354bb84

drivers/pci/devres.c

+27 −27
Original line number Diff line number Diff line
@@ -24,18 +24,16 @@ 
 *

 *    Consequently, in the new API, region requests performed by the pcim_

 *    functions are automatically cleaned up through the devres callback

 *    pcim_addr_resource_release(), while requests performed by

 *    pcim_enable_device() + pci_*region*() are automatically cleaned up

 *    through the for-loop in pcim_release().

 *    pcim_addr_resource_release().

 *

 * TODO 1:

 *    Users of pcim_enable_device() + pci_*region*() are redirected in

 *    pci.c to the managed functions here in this file. This isn't exactly

 *    perfect, but the only alternative way would be to port ALL drivers

 *    using said combination to pcim_ functions.

 *

 * TODO:

 * Remove the legacy table entirely once all calls to pcim_iomap_table() in

 * the kernel have been removed.

 *

 * TODO 2:

 * Port everyone calling pcim_enable_device() + pci_*region*() to using the

 * pcim_ functions. Then, remove all devres functionality from pci_*region*()

 * functions and remove the associated cleanups described above in point #2.

 */



/*
@@ -402,22 +400,6 @@ static void pcim_release(struct device *gendev, void *res) 
{

	struct pci_dev *dev = to_pci_dev(gendev);

	struct pci_devres *this = res;

	int i;



	/*

	 * This is legacy code.

	 *

	 * All regions requested by a pcim_ function do get released through

	 * pcim_addr_resource_release(). Thanks to the hybrid nature of the pci_

	 * region-request functions, this for-loop has to release the regions

	 * if they have been requested by such a function.

	 *

	 * TODO: Remove this once all users of pcim_enable_device() PLUS

	 * pci-region-request-functions have been ported to pcim_ functions.

	 */

	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)

		if (mask_contains_bar(this->region_mask, i))

			pci_release_region(dev, i);



	if (this->mwi)

		pci_clear_mwi(dev);
@@ -826,11 +808,29 @@ static int _pcim_request_region(struct pci_dev *pdev, int bar, const char *name, 
 * The region will automatically be released on driver detach. If desired,

 * release manually only with pcim_release_region().

 */

static int pcim_request_region(struct pci_dev *pdev, int bar, const char *name)

int pcim_request_region(struct pci_dev *pdev, int bar, const char *name)

{

	return _pcim_request_region(pdev, bar, name, 0);

}



/**

 * pcim_request_region_exclusive - Request a PCI BAR exclusively

 * @pdev: PCI device to requestion region for

 * @bar: Index of BAR to request

 * @name: Name associated with the request

 *

 * Returns: 0 on success, a negative error code on failure.

 *

 * Request region specified by @bar exclusively.

 *

 * The region will automatically be released on driver detach. If desired,

 * release manually only with pcim_release_region().

 */

int pcim_request_region_exclusive(struct pci_dev *pdev, int bar, const char *name)

{

	return _pcim_request_region(pdev, bar, name, IORESOURCE_EXCLUSIVE);

}



/**

 * pcim_release_region - Release a PCI BAR

 * @pdev: PCI device to operate on
@@ -839,7 +839,7 @@ static int pcim_request_region(struct pci_dev *pdev, int bar, const char *name) 
 * Release a region manually that was previously requested by

 * pcim_request_region().

 */

static void pcim_release_region(struct pci_dev *pdev, int bar)

void pcim_release_region(struct pci_dev *pdev, int bar)

{

	struct pcim_addr_devres res_searched;

drivers/pci/pci.c

+15 −32
Original line number Diff line number Diff line
@@ -3872,7 +3872,15 @@ EXPORT_SYMBOL(pci_enable_atomic_ops_to_root); 
 */

void pci_release_region(struct pci_dev *pdev, int bar)

{

	struct pci_devres *dr;

	/*

	 * This is done for backwards compatibility, because the old PCI devres

	 * API had a mode in which the function became managed if it had been

	 * enabled with pcim_enable_device() instead of pci_enable_device().

	 */

	if (pci_is_managed(pdev)) {

		pcim_release_region(pdev, bar);

		return;

	}



	if (pci_resource_len(pdev, bar) == 0)

		return;
@@ -3882,21 +3890,6 @@ void pci_release_region(struct pci_dev *pdev, int bar) 
	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)

		release_mem_region(pci_resource_start(pdev, bar),

				pci_resource_len(pdev, bar));



	/*

	 * This devres utility makes this function sometimes managed

	 * (when pcim_enable_device() has been called before).

	 *

	 * This is bad because it conflicts with the pcim_ functions being

	 * exclusively responsible for managed PCI. Its "sometimes yes,

	 * sometimes no" nature can cause bugs.

	 *

	 * TODO: Remove this once all users that use pcim_enable_device() PLUS

	 * a region request function have been ported to using pcim_ functions.

	 */

	dr = find_pci_dr(pdev);

	if (dr)

		dr->region_mask &= ~(1 << bar);

}

EXPORT_SYMBOL(pci_release_region);
@@ -3922,7 +3915,12 @@ EXPORT_SYMBOL(pci_release_region); 
static int __pci_request_region(struct pci_dev *pdev, int bar,

				const char *res_name, int exclusive)

{

	struct pci_devres *dr;

	if (pci_is_managed(pdev)) {

		if (exclusive == IORESOURCE_EXCLUSIVE)

			return pcim_request_region_exclusive(pdev, bar, res_name);



		return pcim_request_region(pdev, bar, res_name);

	}



	if (pci_resource_len(pdev, bar) == 0)

		return 0;
@@ -3938,21 +3936,6 @@ static int __pci_request_region(struct pci_dev *pdev, int bar, 
			goto err_out;

	}



	/*

	 * This devres utility makes this function sometimes managed

	 * (when pcim_enable_device() has been called before).

	 *

	 * This is bad because it conflicts with the pcim_ functions being

	 * exclusively responsible for managed pci. Its "sometimes yes,

	 * sometimes no" nature can cause bugs.

	 *

	 * TODO: Remove this once all users that use pcim_enable_device() PLUS

	 * a region request function have been ported to using pcim_ functions.

	 */

	dr = find_pci_dr(pdev);

	if (dr)

		dr->region_mask |= 1 << bar;



	return 0;



err_out:

drivers/pci/pci.h

+5 −6
Original line number Diff line number Diff line
@@ -826,16 +826,15 @@ struct pci_devres { 
	unsigned int orig_intx:1;

	unsigned int restore_intx:1;

	unsigned int mwi:1;



	/*

	 * TODO: remove the region_mask once everyone calling

	 * pcim_enable_device() + pci_*region*() is ported to pcim_ functions.

	 */

	u32 region_mask;

};



struct pci_devres *find_pci_dr(struct pci_dev *pdev);



int pcim_request_region(struct pci_dev *pdev, int bar, const char *name);

int pcim_request_region_exclusive(struct pci_dev *pdev, int bar,

				  const char *name);

void pcim_release_region(struct pci_dev *pdev, int bar);



/*

 * Config Address for PCI Configuration Mechanism #1

 *