[PATCH v4 0/7] Expose and manage PCI device reset

[PATCH v4 0/7] Expose and manage PCI device reset

[Amey Narkhede]

PCI and PCIe devices may support a number of possible reset mechanisms
for example Function Level Reset (FLR) provided via Advanced Feature or
PCIe capabilities, Power Management reset, bus reset, or device specific reset.
Currently the PCI subsystem creates a policy prioritizing these reset methods
which provides neither visibility nor control to userspace.

Expose the reset methods available per device to userspace, via sysfs
and allow an administrative user or device owner to have ability to
manage per device reset method priorities or exclusions.
This feature aims to allow greater control of a device for use cases
as device assignment, where specific device or platform issues may
interact poorly with a given reset method, and for which device specific
quirks have not been developed.

The error handling might be too verbose in the last patch
("PCI: Change the type of probe argument in reset functions").
Please let me know your comments.

Changes in v4:
	- Change the order or strlen and strim in reset_method_store
	  function to avoid extra strlen call.
	- Use consistent terminology in new
	  pci_reset_mode enum and rename the probe argument
	  of reset functions.

Changes in v3:
	- Dropped "PCI: merge slot and bus reset implementations" which was
	  already accepted separately
	- Grammar fixes
	- Added Shanker's patches which were rebased on v2 of this series
	- Added "PCI: Change the type of probe argument in reset functions"
	  and additional user input sanitization code in reset_method_store
	  function per review feedback from Krzysztof

Changes in v2:
	- Use byte array instead of bitmap to keep track of
	  ordering of reset methods
	- Fix incorrect use of reset_fn field in octeon driver
	- Allow writing comma separated list of names of supported reset
	  methods to reset_method sysfs attribute
	- Writing empty string instead of "none" to reset_method attribute
	  disables ability of reset the device


Amey Narkhede (5):
  PCI: Add pcie_reset_flr to follow calling convention of other reset
    methods
  PCI: Add new array for keeping track of ordering of reset methods
  PCI: Remove reset_fn field from pci_dev
  PCI/sysfs: Allow userspace to query and set device reset mechanism
  PCI: Change the type of probe argument in reset functions

Shanker Donthineni (2):
  PCI: Add support for a function level reset based on _RST method
  PCI: Enable NO_BUS_RESET quirk for Nvidia GPUs

 Documentation/ABI/testing/sysfs-bus-pci       |  16 +
 drivers/crypto/cavium/nitrox/nitrox_main.c    |   4 +-
 .../ethernet/cavium/liquidio/lio_vf_main.c    |   2 +-
 drivers/pci/hotplug/pciehp.h                  |   2 +-
 drivers/pci/hotplug/pciehp_hpc.c              |   7 +-
 drivers/pci/pci-sysfs.c                       |  98 ++++++-
 drivers/pci/pci.c                             | 274 ++++++++++++------
 drivers/pci/pci.h                             |  14 +-
 drivers/pci/pcie/aer.c                        |  12 +-
 drivers/pci/probe.c                           |   4 +-
 drivers/pci/quirks.c                          |  50 ++--
 include/linux/pci.h                           |  16 +-
 include/linux/pci_hotplug.h                   |   2 +-
 13 files changed, 360 insertions(+), 141 deletions(-)

--
2.31.1

[PATCH v4 1/7] PCI: Add pcie_reset_flr to follow calling convention of other reset methods

[Amey Narkhede]

Currently there is separate function pcie_has_flr to probe
if pcie flr is supported by the device which does not match
the calling convention followed by reset methods which use second
function argument to decide whether to probe or not.
Add new function pcie_reset_flr that follows the calling
convention of reset methods.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 drivers/crypto/cavium/nitrox/nitrox_main.c |  4 +-
 drivers/pci/pci.c                          | 62 ++++++++++++----------
 drivers/pci/pcie/aer.c                     | 12 ++---
 drivers/pci/quirks.c                       |  9 ++--
 include/linux/pci.h                        |  2 +-
 5 files changed, 43 insertions(+), 46 deletions(-)

diff --git a/drivers/crypto/cavium/nitrox/nitrox_main.c b/drivers/crypto/cavium/nitrox/nitrox_main.c
index facc8e6bc..15d6c8452 100644
--- a/drivers/crypto/cavium/nitrox/nitrox_main.c
+++ b/drivers/crypto/cavium/nitrox/nitrox_main.c
@@ -306,9 +306,7 @@ static int nitrox_device_flr(struct pci_dev *pdev)
 		return -ENOMEM;
 	}
 
-	/* check flr support */
-	if (pcie_has_flr(pdev))
-		pcie_flr(pdev);
+	pcie_reset_flr(pdev, 0);
 
 	pci_restore_state(pdev);
 
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8f79804c6..7cacb6d21 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4573,32 +4573,12 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_wait_for_pending_transaction);
 
-/**
- * pcie_has_flr - check if a device supports function level resets
- * @dev: device to check
- *
- * Returns true if the device advertises support for PCIe function level
- * resets.
- */
-bool pcie_has_flr(struct pci_dev *dev)
-{
-	u32 cap;
-
-	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
-		return false;
-
-	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
-	return cap & PCI_EXP_DEVCAP_FLR;
-}
-EXPORT_SYMBOL_GPL(pcie_has_flr);
-
 /**
  * pcie_flr - initiate a PCIe function level reset
  * @dev: device to reset
  *
- * Initiate a function level reset on @dev.  The caller should ensure the
- * device supports FLR before calling this function, e.g. by using the
- * pcie_has_flr() helper.
+ * Initiate a function level reset unconditionally on @dev without
+ * checking any flags and DEVCAP
  */
 int pcie_flr(struct pci_dev *dev)
 {
@@ -4621,6 +4601,31 @@ int pcie_flr(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pcie_flr);
 
+/**
+ * pcie_reset_flr - initiate a PCIe function level reset
+ * @dev: device to reset
+ * @probe: If set, only check if the device can be reset this way.
+ *
+ * Initiate a function level reset on @dev.
+ */
+int pcie_reset_flr(struct pci_dev *dev, int probe)
+{
+	u32 cap;
+
+	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
+		return -ENOTTY;
+
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+	if (!(cap & PCI_EXP_DEVCAP_FLR))
+		return -ENOTTY;
+
+	if (probe)
+		return 0;
+
+	return pcie_flr(dev);
+}
+EXPORT_SYMBOL_GPL(pcie_reset_flr);
+
 static int pci_af_flr(struct pci_dev *dev, int probe)
 {
 	int pos;
@@ -5100,11 +5105,9 @@ int __pci_reset_function_locked(struct pci_dev *dev)
 	rc = pci_dev_specific_reset(dev, 0);
 	if (rc != -ENOTTY)
 		return rc;
-	if (pcie_has_flr(dev)) {
-		rc = pcie_flr(dev);
-		if (rc != -ENOTTY)
-			return rc;
-	}
+	rc = pcie_reset_flr(dev, 0);
+	if (rc != -ENOTTY)
+		return rc;
 	rc = pci_af_flr(dev, 0);
 	if (rc != -ENOTTY)
 		return rc;
@@ -5135,8 +5138,9 @@ int pci_probe_reset_function(struct pci_dev *dev)
 	rc = pci_dev_specific_reset(dev, 1);
 	if (rc != -ENOTTY)
 		return rc;
-	if (pcie_has_flr(dev))
-		return 0;
+	rc = pcie_reset_flr(dev, 1);
+	if (rc != -ENOTTY)
+		return rc;
 	rc = pci_af_flr(dev, 1);
 	if (rc != -ENOTTY)
 		return rc;
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index ba2238834..f4e891bd5 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1405,13 +1405,11 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 	}
 
 	if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) {
-		if (pcie_has_flr(dev)) {
-			rc = pcie_flr(dev);
-			pci_info(dev, "has been reset (%d)\n", rc);
-		} else {
-			pci_info(dev, "not reset (no FLR support)\n");
-			rc = -ENOTTY;
-		}
+		rc = pcie_reset_flr(dev, 0);
+		if (!rc)
+			pci_info(dev, "has been reset\n");
+		else
+			pci_info(dev, "not reset (no FLR support: %d)\n", rc);
 	} else {
 		rc = pci_bus_error_reset(dev);
 		pci_info(dev, "%s Port link has been reset (%d)\n",
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 653660e3b..5318833f3 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3831,7 +3831,7 @@ static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
 	u32 cfg;
 
 	if (dev->class != PCI_CLASS_STORAGE_EXPRESS ||
-	    !pcie_has_flr(dev) || !pci_resource_start(dev, 0))
+	    pcie_reset_flr(dev, 1) || !pci_resource_start(dev, 0))
 		return -ENOTTY;
 
 	if (probe)
@@ -3900,13 +3900,10 @@ static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
  */
 static int delay_250ms_after_flr(struct pci_dev *dev, int probe)
 {
-	if (!pcie_has_flr(dev))
-		return -ENOTTY;
+	int ret = pcie_reset_flr(dev, probe);
 
 	if (probe)
-		return 0;
-
-	pcie_flr(dev);
+		return ret;
 
 	msleep(250);
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 86c799c97..35c8e9e7e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1217,7 +1217,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
 			     enum pci_bus_speed *speed,
 			     enum pcie_link_width *width);
 void pcie_print_link_status(struct pci_dev *dev);
-bool pcie_has_flr(struct pci_dev *dev);
+int pcie_reset_flr(struct pci_dev *dev, int probe);
 int pcie_flr(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
-- 
2.31.1

[PATCH v4 2/7] PCI: Add new array for keeping track of ordering of reset methods

[Amey Narkhede]

Introduce a new array reset_methods in struct pci_dev
to keep track of reset mechanisms supported by the
device and their ordering. Also refactor probing and reset
functions to take advantage of calling convention of reset
functions.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 drivers/pci/pci.c   | 107 ++++++++++++++++++++++++++------------------
 drivers/pci/pci.h   |   8 +++-
 drivers/pci/probe.c |   5 +--
 include/linux/pci.h |   7 +++
 4 files changed, 80 insertions(+), 47 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7cacb6d21..cbdb5bd0d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -72,6 +72,14 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
 		msleep(delay);
 }
 
+bool pci_reset_supported(struct pci_dev *dev)
+{
+	u8 null_reset_methods[PCI_RESET_METHODS_NUM] = { 0 };
+
+	return memcmp(null_reset_methods,
+		      dev->reset_methods, PCI_RESET_METHODS_NUM);
+}
+
 #ifdef CONFIG_PCI_DOMAINS
 int pci_domains_supported = 1;
 #endif
@@ -5068,6 +5076,19 @@ static void pci_dev_restore(struct pci_dev *dev)
 		err_handler->reset_done(dev);
 }
 
+/*
+ * The ordering for functions in pci_reset_fn_methods
+ * is required for reset_methods byte array defined
+ * in struct pci_dev.
+ */
+const struct pci_reset_fn_method pci_reset_fn_methods[] = {
+	{ &pci_dev_specific_reset, .name = "device_specific" },
+	{ &pcie_reset_flr, .name = "flr" },
+	{ &pci_af_flr, .name = "af_flr" },
+	{ &pci_pm_reset, .name = "pm" },
+	{ &pci_reset_bus_function, .name = "bus" },
+};
+
 /**
  * __pci_reset_function_locked - reset a PCI device function while holding
  * the @dev mutex lock.
@@ -5090,65 +5111,65 @@ static void pci_dev_restore(struct pci_dev *dev)
  */
 int __pci_reset_function_locked(struct pci_dev *dev)
 {
-	int rc;
+	int i, rc = -ENOTTY;
+	u8 prio;
 
 	might_sleep();
 
-	/*
-	 * A reset method returns -ENOTTY if it doesn't support this device
-	 * and we should try the next method.
-	 *
-	 * If it returns 0 (success), we're finished.  If it returns any
-	 * other error, we're also finished: this indicates that further
-	 * reset mechanisms might be broken on the device.
-	 */
-	rc = pci_dev_specific_reset(dev, 0);
-	if (rc != -ENOTTY)
-		return rc;
-	rc = pcie_reset_flr(dev, 0);
-	if (rc != -ENOTTY)
-		return rc;
-	rc = pci_af_flr(dev, 0);
-	if (rc != -ENOTTY)
-		return rc;
-	rc = pci_pm_reset(dev, 0);
-	if (rc != -ENOTTY)
-		return rc;
-	return pci_reset_bus_function(dev, 0);
+	for (prio = PCI_RESET_METHODS_NUM; prio; prio--) {
+		for (i = 0; i < PCI_RESET_METHODS_NUM; i++) {
+			if (dev->reset_methods[i] == prio) {
+				/*
+				 * A reset method returns -ENOTTY if it doesn't support this device
+				 * and we should try the next method.
+				 *
+				 * If it returns 0 (success), we're finished.  If it returns any
+				 * other error, we're also finished: this indicates that further
+				 * reset mechanisms might be broken on the device.
+				 */
+				rc = pci_reset_fn_methods[i].reset_fn(dev, 0);
+				if (rc != -ENOTTY)
+					return rc;
+				break;
+			}
+		}
+		if (i == PCI_RESET_METHODS_NUM)
+			break;
+	}
+	return rc;
 }
 EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
 
 /**
- * pci_probe_reset_function - check whether the device can be safely reset
- * @dev: PCI device to reset
+ * pci_init_reset_methods - check whether device can be safely reset
+ * and store supported reset mechanisms.
+ * @dev: PCI device to check for reset mechanisms
  *
  * Some devices allow an individual function to be reset without affecting
  * other functions in the same device.  The PCI device must be responsive
- * to PCI config space in order to use this function.
+ * to reads and writes to its PCI config space in order to use this function.
  *
- * Returns 0 if the device function can be reset or negative if the
- * device doesn't support resetting a single function.
+ * Stores reset mechanisms supported by device in reset_methods byte array
+ * which is a member of struct pci_dev.
  */
-int pci_probe_reset_function(struct pci_dev *dev)
+void pci_init_reset_methods(struct pci_dev *dev)
 {
-	int rc;
+	int i, rc;
+	u8 prio = PCI_RESET_METHODS_NUM;
+	u8 reset_methods[PCI_RESET_METHODS_NUM] = { 0 };
 
-	might_sleep();
+	BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_RESET_METHODS_NUM);
 
-	rc = pci_dev_specific_reset(dev, 1);
-	if (rc != -ENOTTY)
-		return rc;
-	rc = pcie_reset_flr(dev, 1);
-	if (rc != -ENOTTY)
-		return rc;
-	rc = pci_af_flr(dev, 1);
-	if (rc != -ENOTTY)
-		return rc;
-	rc = pci_pm_reset(dev, 1);
-	if (rc != -ENOTTY)
-		return rc;
+	might_sleep();
 
-	return pci_reset_bus_function(dev, 1);
+	for (i = 0; i < PCI_RESET_METHODS_NUM; i++) {
+		rc = pci_reset_fn_methods[i].reset_fn(dev, 1);
+		if (!rc)
+			reset_methods[i] = prio--;
+		else if (rc != -ENOTTY)
+			break;
+	}
+	memcpy(dev->reset_methods, reset_methods, sizeof(reset_methods));
 }
 
 /**
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index ef7c46613..1b3ba3116 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -39,7 +39,7 @@ enum pci_mmap_api {
 int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai,
 		  enum pci_mmap_api mmap_api);
 
-int pci_probe_reset_function(struct pci_dev *dev);
+void pci_init_reset_methods(struct pci_dev *dev);
 int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
 int pci_bus_error_reset(struct pci_dev *dev);
 
@@ -612,6 +612,12 @@ struct pci_dev_reset_methods {
 	int (*reset)(struct pci_dev *dev, int probe);
 };
 
+struct pci_reset_fn_method {
+	int (*reset_fn)(struct pci_dev *, int probe);
+	char *name;
+};
+
+extern const struct pci_reset_fn_method pci_reset_fn_methods[];
 #ifdef CONFIG_PCI_QUIRKS
 int pci_dev_specific_reset(struct pci_dev *dev, int probe);
 #else
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 953f15abc..c5cfdd239 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2403,9 +2403,8 @@ static void pci_init_capabilities(struct pci_dev *dev)
 	pci_rcec_init(dev);		/* Root Complex Event Collector */
 
 	pcie_report_downtraining(dev);
-
-	if (pci_probe_reset_function(dev) == 0)
-		dev->reset_fn = 1;
+	pci_init_reset_methods(dev);
+	dev->reset_fn = pci_reset_supported(dev);
 }
 
 /*
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 35c8e9e7e..738c0cadb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -49,6 +49,8 @@
 			       PCI_STATUS_SIG_TARGET_ABORT | \
 			       PCI_STATUS_PARITY)
 
+#define PCI_RESET_METHODS_NUM 5
+
 /*
  * The PCI interface treats multi-function devices as independent
  * devices.  The slot/function address of each device is encoded
@@ -506,6 +508,10 @@ struct pci_dev {
 	char		*driver_override; /* Driver name to force a match */
 
 	unsigned long	priv_flags;	/* Private flags for the PCI driver */
+	/*
+	 * See pci_reset_fn_methods array in pci.c for ordering.
+	 */
+	u8 reset_methods[PCI_RESET_METHODS_NUM];	/* Reset methods ordered by priority */
 };
 
 static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
@@ -1219,6 +1225,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
 void pcie_print_link_status(struct pci_dev *dev);
 int pcie_reset_flr(struct pci_dev *dev, int probe);
 int pcie_flr(struct pci_dev *dev);
+bool pci_reset_supported(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
 int pci_reset_function_locked(struct pci_dev *dev);
-- 
2.31.1

[PATCH v4 3/7] PCI: Remove reset_fn field from pci_dev

[Amey Narkhede]

reset_fn field is used to indicate whether the
device supports any reset mechanism or not.
Deprecate use of reset_fn in favor of new
reset_methods array which can be used to keep
track of all supported reset mechanisms of a device
and their ordering.
The octeon driver is incorrectly using reset_fn field
to detect if the device supports FLR or not. Use
pcie_reset_flr to probe whether it supports
FLR or not.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 drivers/net/ethernet/cavium/liquidio/lio_vf_main.c | 2 +-
 drivers/pci/pci-sysfs.c                            | 6 ++----
 drivers/pci/pci.c                                  | 6 +++---
 drivers/pci/probe.c                                | 1 -
 drivers/pci/quirks.c                               | 2 +-
 include/linux/pci.h                                | 1 -
 6 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
index 516f166ce..336d149ee 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
@@ -526,7 +526,7 @@ static void octeon_destroy_resources(struct octeon_device *oct)
 			oct->irq_name_storage = NULL;
 		}
 		/* Soft reset the octeon device before exiting */
-		if (oct->pci_dev->reset_fn)
+		if (!pcie_reset_flr(oct->pci_dev, 1))
 			octeon_pci_flr(oct);
 		else
 			cn23xx_vf_ask_pf_to_do_flr(oct);
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index f8afd54ca..388895099 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1334,7 +1334,7 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev)
 
 	pcie_vpd_create_sysfs_dev_files(dev);
 
-	if (dev->reset_fn) {
+	if (pci_reset_supported(dev)) {
 		retval = device_create_file(&dev->dev, &dev_attr_reset);
 		if (retval)
 			goto error;
@@ -1417,10 +1417,8 @@ int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
 static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
 {
 	pcie_vpd_remove_sysfs_dev_files(dev);
-	if (dev->reset_fn) {
+	if (pci_reset_supported(dev))
 		device_remove_file(&dev->dev, &dev_attr_reset);
-		dev->reset_fn = 0;
-	}
 }
 
 /**
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index cbdb5bd0d..fad209c5f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5192,7 +5192,7 @@ int pci_reset_function(struct pci_dev *dev)
 {
 	int rc;
 
-	if (!dev->reset_fn)
+	if (!pci_reset_supported(dev))
 		return -ENOTTY;
 
 	pci_dev_lock(dev);
@@ -5228,7 +5228,7 @@ int pci_reset_function_locked(struct pci_dev *dev)
 {
 	int rc;
 
-	if (!dev->reset_fn)
+	if (!pci_reset_supported(dev))
 		return -ENOTTY;
 
 	pci_dev_save_and_disable(dev);
@@ -5251,7 +5251,7 @@ int pci_try_reset_function(struct pci_dev *dev)
 {
 	int rc;
 
-	if (!dev->reset_fn)
+	if (!pci_reset_supported(dev))
 		return -ENOTTY;
 
 	if (!pci_dev_trylock(dev))
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c5cfdd239..4764e031a 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2404,7 +2404,6 @@ static void pci_init_capabilities(struct pci_dev *dev)
 
 	pcie_report_downtraining(dev);
 	pci_init_reset_methods(dev);
-	dev->reset_fn = pci_reset_supported(dev);
 }
 
 /*
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 5318833f3..8f47d139c 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5535,7 +5535,7 @@ static void quirk_reset_lenovo_thinkpad_p50_nvgpu(struct pci_dev *pdev)
 
 	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
 	    pdev->subsystem_device != 0x222e ||
-	    !pdev->reset_fn)
+	    !pci_reset_supported(pdev))
 		return;
 
 	if (pci_enable_device_mem(pdev))
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 738c0cadb..e9603d638 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -429,7 +429,6 @@ struct pci_dev {
 	unsigned int	state_saved:1;
 	unsigned int	is_physfn:1;
 	unsigned int	is_virtfn:1;
-	unsigned int	reset_fn:1;
 	unsigned int	is_hotplug_bridge:1;
 	unsigned int	shpc_managed:1;		/* SHPC owned by shpchp */
 	unsigned int	is_thunderbolt:1;	/* Thunderbolt controller */
-- 
2.31.1

[PATCH v4 4/7] PCI/sysfs: Allow userspace to query and set device reset mechanism

[Amey Narkhede]

Add reset_method sysfs attribute to enable user to
query and set user preferred device reset methods and
their ordering.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-pci | 16 +++++
 drivers/pci/pci-sysfs.c                 | 96 ++++++++++++++++++++++++-
 2 files changed, 109 insertions(+), 3 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 25c9c3977..36fba7ebf 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -121,6 +121,22 @@ Description:
 		child buses, and re-discover devices removed earlier
 		from this part of the device tree.
 
+What:		/sys/bus/pci/devices/.../reset_method
+Date:		March 2021
+Contact:	Amey Narkhede <ameynarkhede03@gmail.com>
+Description:
+		Some devices allow an individual function to be reset
+		without affecting other functions in the same slot.
+		For devices that have this support, a file named reset_method
+		will be present in sysfs. Reading this file will give names
+		of the device supported reset methods and their ordering.
+		Writing the name or comma separated list of names of any of
+		the device supported reset methods to this file will set the
+		reset methods and their ordering to be used when resetting
+		the device. Writing empty string to this file will disable
+		ability to reset the device and writing "default" will return
+		to the original value.
+
 What:		/sys/bus/pci/devices/.../reset
 Date:		July 2009
 Contact:	Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 388895099..1c715b262 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1304,6 +1304,89 @@ static const struct bin_attribute pcie_config_attr = {
 	.write = pci_write_config,
 };
 
+static ssize_t reset_method_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	ssize_t len = 0;
+	int i, prio;
+
+	for (prio = PCI_RESET_METHODS_NUM; prio; prio--) {
+		for (i = 0; i < PCI_RESET_METHODS_NUM; i++) {
+			if (prio == pdev->reset_methods[i]) {
+				len += sysfs_emit_at(buf, len, "%s%s",
+						     len ? "," : "",
+						     pci_reset_fn_methods[i].name);
+				break;
+			}
+		}
+
+		if (i == PCI_RESET_METHODS_NUM)
+			break;
+	}
+
+	return len;
+}
+
+static ssize_t reset_method_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	u8 reset_methods[PCI_RESET_METHODS_NUM];
+	struct pci_dev *pdev = to_pci_dev(dev);
+	u8 prio = PCI_RESET_METHODS_NUM;
+	char *name;
+	int i;
+
+	/*
+	 * Initialize reset_method such that 0xff indicates
+	 * supported but not currently enabled reset methods
+	 * as we only use priority values which are within
+	 * the range of PCI_RESET_FN_METHODS array size
+	 */
+	for (i = 0; i < PCI_RESET_METHODS_NUM; i++)
+		reset_methods[i] = pdev->reset_methods[i] ? 0xff : 0;
+
+	if (sysfs_streq(buf, "")) {
+		pci_warn(pdev, "All device reset methods disabled by user");
+		goto set_reset_methods;
+	}
+
+	if (sysfs_streq(buf, "default")) {
+		for (i = 0; i < PCI_RESET_METHODS_NUM; i++)
+			reset_methods[i] = reset_methods[i] ? prio-- : 0;
+		goto set_reset_methods;
+	}
+
+	while ((name = strsep((char **)&buf, ",")) != NULL) {
+		if (!strlen(name))
+			continue;
+
+		name = strim(name);
+
+		for (i = 0; i < PCI_RESET_METHODS_NUM; i++) {
+			if (reset_methods[i] &&
+			    sysfs_streq(name, pci_reset_fn_methods[i].name)) {
+				reset_methods[i] = prio--;
+				break;
+			}
+		}
+		if (i == PCI_RESET_METHODS_NUM)
+			return -EINVAL;
+	}
+
+	if (reset_methods[0] &&
+	    reset_methods[0] != PCI_RESET_METHODS_NUM)
+		pci_warn(pdev, "Device specific reset disabled/de-prioritized by user");
+
+set_reset_methods:
+	memcpy(pdev->reset_methods, reset_methods, sizeof(reset_methods));
+	return count;
+}
+
+static DEVICE_ATTR_RW(reset_method);
+
 static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
 			   const char *buf, size_t count)
 {
@@ -1337,11 +1420,16 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev)
 	if (pci_reset_supported(dev)) {
 		retval = device_create_file(&dev->dev, &dev_attr_reset);
 		if (retval)
-			goto error;
+			goto err_reset;
+		retval = device_create_file(&dev->dev, &dev_attr_reset_method);
+		if (retval)
+			goto err_method;
 	}
 	return 0;
 
-error:
+err_method:
+	device_remove_file(&dev->dev, &dev_attr_reset);
+err_reset:
 	pcie_vpd_remove_sysfs_dev_files(dev);
 	return retval;
 }
@@ -1417,8 +1505,10 @@ int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
 static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
 {
 	pcie_vpd_remove_sysfs_dev_files(dev);
-	if (pci_reset_supported(dev))
+	if (pci_reset_supported(dev)) {
 		device_remove_file(&dev->dev, &dev_attr_reset);
+		device_remove_file(&dev->dev, &dev_attr_reset_method);
+	}
 }
 
 /**
-- 
2.31.1

[PATCH v4 5/7] PCI: Add support for a function level reset based on _RST method

[Amey Narkhede]

From: Shanker Donthineni <sdonthineni@nvidia.com>

The _RST is a standard method specified in the ACPI specification. It
provides a function level reset when it is described in the acpi_device
context associated with PCI-device.

Implement a new reset function pci_dev_acpi_reset() for probing RST
method and execute if it is defined in the firmware. The ACPI binding
information is available only after calling device_add(), so move
pci_init_reset_methods() to end of the pci_device_add().

The default priority of the acpi reset is set to below device-specific
and above hardware resets.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
---
 drivers/pci/pci.c   | 30 ++++++++++++++++++++++++++++++
 drivers/pci/probe.c |  2 +-
 include/linux/pci.h |  2 +-
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index fad209c5f..1d859b100 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5076,6 +5076,35 @@ static void pci_dev_restore(struct pci_dev *dev)
 		err_handler->reset_done(dev);
 }
 
+/**
+ * pci_dev_acpi_reset - do a function level reset using _RST method
+ * @dev: device to reset
+ * @probe: check if _RST method is included in the acpi_device context.
+ */
+static int pci_dev_acpi_reset(struct pci_dev *dev, int probe)
+{
+#ifdef CONFIG_ACPI
+	acpi_handle handle = ACPI_HANDLE(&dev->dev);
+
+	/* Return -ENOTTY if _RST method is not included in the dev context */
+	if (!handle || !acpi_has_method(handle, "_RST"))
+		return -ENOTTY;
+
+	/* Return 0 for probe phase indicating that we can reset this device */
+	if (probe)
+		return 0;
+
+	/* Invoke _RST() method to perform a function level reset */
+	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) {
+		pci_warn(dev, "Failed to reset the device\n");
+		return -EINVAL;
+	}
+	return 0;
+#else
+	return -ENOTTY;
+#endif
+}
+
 /*
  * The ordering for functions in pci_reset_fn_methods
  * is required for reset_methods byte array defined
@@ -5083,6 +5112,7 @@ static void pci_dev_restore(struct pci_dev *dev)
  */
 const struct pci_reset_fn_method pci_reset_fn_methods[] = {
 	{ &pci_dev_specific_reset, .name = "device_specific" },
+	{ &pci_dev_acpi_reset, .name = "acpi" },
 	{ &pcie_reset_flr, .name = "flr" },
 	{ &pci_af_flr, .name = "af_flr" },
 	{ &pci_pm_reset, .name = "pm" },
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4764e031a..d4becd6ff 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2403,7 +2403,6 @@ static void pci_init_capabilities(struct pci_dev *dev)
 	pci_rcec_init(dev);		/* Root Complex Event Collector */
 
 	pcie_report_downtraining(dev);
-	pci_init_reset_methods(dev);
 }
 
 /*
@@ -2494,6 +2493,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	dev->match_driver = false;
 	ret = device_add(&dev->dev);
 	WARN_ON(ret < 0);
+	pci_init_reset_methods(dev);
 }
 
 struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index e9603d638..9bec3c616 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -49,7 +49,7 @@
 			       PCI_STATUS_SIG_TARGET_ABORT | \
 			       PCI_STATUS_PARITY)
 
-#define PCI_RESET_METHODS_NUM 5
+#define PCI_RESET_METHODS_NUM 6
 
 /*
  * The PCI interface treats multi-function devices as independent
-- 
2.31.1

[PATCH v4 6/7] PCI: Enable NO_BUS_RESET quirk for Nvidia GPUs

[Amey Narkhede]

From: Shanker Donthineni <sdonthineni@nvidia.com>

On select platforms, some Nvidia GPU devices do not work with SBR.
Triggering SBR would leave the device inoperable for the current
system boot. It requires a system hard-reboot to get the GPU device
back to normal operating condition post-SBR. For the affected
devices, enable NO_BUS_RESET quirk to fix the issue.

This issue will be fixed in the next generation of hardware.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
---
 drivers/pci/quirks.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 8f47d139c..ceec67342 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3558,6 +3558,18 @@ static void quirk_no_bus_reset(struct pci_dev *dev)
 	dev->dev_flags |= PCI_DEV_FLAGS_NO_BUS_RESET;
 }
 
+/*
+ * Some Nvidia GPU devices do not work with bus reset, SBR needs to be
+ * prevented for those affected devices.
+ */
+static void quirk_nvidia_no_bus_reset(struct pci_dev *dev)
+{
+	if ((dev->device & 0xffc0) == 0x2340)
+		quirk_no_bus_reset(dev);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+			 quirk_nvidia_no_bus_reset);
+
 /*
  * Some Atheros AR9xxx and QCA988x chips do not behave after a bus reset.
  * The device will throw a Link Down error on AER-capable systems and
-- 
2.31.1

[PATCH v4 7/7] PCI: Change the type of probe argument in reset functions

[Amey Narkhede]

Introduce a new enum pci_reset_mode_t to make the context
of probe argument in reset functions clear and the code
easier to read.
Change the type of probe argument in functions which implement
reset methods from int to pci_reset_mode_t to make the intent clear.
Add a new line in return statement of pci_reset_bus_function.

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Suggested-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
---
 drivers/crypto/cavium/nitrox/nitrox_main.c    |  2 +-
 .../ethernet/cavium/liquidio/lio_vf_main.c    |  2 +-
 drivers/pci/hotplug/pciehp.h                  |  2 +-
 drivers/pci/hotplug/pciehp_hpc.c              |  7 +-
 drivers/pci/pci.c                             | 95 ++++++++++++-------
 drivers/pci/pci.h                             |  8 +-
 drivers/pci/pcie/aer.c                        |  2 +-
 drivers/pci/quirks.c                          | 33 ++++---
 include/linux/pci.h                           |  8 +-
 include/linux/pci_hotplug.h                   |  2 +-
 10 files changed, 103 insertions(+), 58 deletions(-)

diff --git a/drivers/crypto/cavium/nitrox/nitrox_main.c b/drivers/crypto/cavium/nitrox/nitrox_main.c
index 15d6c8452..f97fa8e99 100644
--- a/drivers/crypto/cavium/nitrox/nitrox_main.c
+++ b/drivers/crypto/cavium/nitrox/nitrox_main.c
@@ -306,7 +306,7 @@ static int nitrox_device_flr(struct pci_dev *pdev)
 		return -ENOMEM;
 	}

-	pcie_reset_flr(pdev, 0);
+	pcie_reset_flr(pdev, PCI_RESET_DO_RESET);

 	pci_restore_state(pdev);

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
index 336d149ee..6e666be69 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
@@ -526,7 +526,7 @@ static void octeon_destroy_resources(struct octeon_device *oct)
 			oct->irq_name_storage = NULL;
 		}
 		/* Soft reset the octeon device before exiting */
-		if (!pcie_reset_flr(oct->pci_dev, 1))
+		if (!pcie_reset_flr(oct->pci_dev, PCI_RESET_PROBE))
 			octeon_pci_flr(oct);
 		else
 			cn23xx_vf_ask_pf_to_do_flr(oct);
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 4fd200d8b..87da03adc 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -181,7 +181,7 @@ void pciehp_release_ctrl(struct controller *ctrl);

 int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot);
 int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot);
-int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, int probe);
+int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, pci_reset_mode_t mode);
 int pciehp_get_attention_status(struct hotplug_slot *hotplug_slot, u8 *status);
 int pciehp_set_raw_indicator_status(struct hotplug_slot *h_slot, u8 status);
 int pciehp_get_raw_indicator_status(struct hotplug_slot *h_slot, u8 *status);
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index fb3840e22..a99b828ae 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -834,14 +834,17 @@ void pcie_disable_interrupt(struct controller *ctrl)
  * momentarily, if we see that they could interfere. Also, clear any spurious
  * events after.
  */
-int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, int probe)
+int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, pci_reset_mode_t mode)
 {
 	struct controller *ctrl = to_ctrl(hotplug_slot);
 	struct pci_dev *pdev = ctrl_dev(ctrl);
 	u16 stat_mask = 0, ctrl_mask = 0;
 	int rc;

-	if (probe)
+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	down_write(&ctrl->reset_lock);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1d859b100..c6fef081c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4616,10 +4616,13 @@ EXPORT_SYMBOL_GPL(pcie_flr);
  *
  * Initiate a function level reset on @dev.
  */
-int pcie_reset_flr(struct pci_dev *dev, int probe)
+int pcie_reset_flr(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	u32 cap;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
 		return -ENOTTY;

@@ -4627,18 +4630,21 @@ int pcie_reset_flr(struct pci_dev *dev, int probe)
 	if (!(cap & PCI_EXP_DEVCAP_FLR))
 		return -ENOTTY;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	return pcie_flr(dev);
 }
 EXPORT_SYMBOL_GPL(pcie_reset_flr);

-static int pci_af_flr(struct pci_dev *dev, int probe)
+static int pci_af_flr(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	int pos;
 	u8 cap;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	pos = pci_find_capability(dev, PCI_CAP_ID_AF);
 	if (!pos)
 		return -ENOTTY;
@@ -4650,7 +4656,7 @@ static int pci_af_flr(struct pci_dev *dev, int probe)
 	if (!(cap & PCI_AF_CAP_TP) || !(cap & PCI_AF_CAP_FLR))
 		return -ENOTTY;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	/*
@@ -4693,10 +4699,13 @@ static int pci_af_flr(struct pci_dev *dev, int probe)
  * by default (i.e. unless the @dev's d3hot_delay field has a different value).
  * Moreover, only devices in D0 can be reset by this function.
  */
-static int pci_pm_reset(struct pci_dev *dev, int probe)
+static int pci_pm_reset(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	u16 csr;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (!dev->pm_cap || dev->dev_flags & PCI_DEV_FLAGS_NO_PM_RESET)
 		return -ENOTTY;

@@ -4704,7 +4713,7 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
 	if (csr & PCI_PM_CTRL_NO_SOFT_RESET)
 		return -ENOTTY;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	if (dev->current_state != PCI_D0)
@@ -4953,10 +4962,13 @@ int pci_bridge_secondary_bus_reset(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_bridge_secondary_bus_reset);

-static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
+static int pci_parent_bus_reset(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	struct pci_dev *pdev;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (pci_is_root_bus(dev->bus) || dev->subordinate ||
 	    !dev->bus->self || dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
 		return -ENOTTY;
@@ -4965,43 +4977,53 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
 		if (pdev != dev)
 			return -ENOTTY;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	return pci_bridge_secondary_bus_reset(dev->bus->self);
 }

-static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, int probe)
+static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, pci_reset_mode_t mode)
 {
 	int rc = -ENOTTY;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (!hotplug || !try_module_get(hotplug->owner))
 		return rc;

 	if (hotplug->ops->reset_slot)
-		rc = hotplug->ops->reset_slot(hotplug, probe);
+		rc = hotplug->ops->reset_slot(hotplug, mode);

 	module_put(hotplug->owner);

 	return rc;
 }

-static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
+static int pci_dev_reset_slot_function(struct pci_dev *dev, pci_reset_mode_t mode)
 {
+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (dev->multifunction || dev->subordinate || !dev->slot ||
 	    dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
 		return -ENOTTY;

-	return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
+	return pci_reset_hotplug_slot(dev->slot->hotplug, mode);
 }

-static int pci_reset_bus_function(struct pci_dev *dev, int probe)
+static int pci_reset_bus_function(struct pci_dev *dev, pci_reset_mode_t mode)
 {
-	int rc = pci_dev_reset_slot_function(dev, probe);
+	int rc = pci_dev_reset_slot_function(dev, mode);
+
+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;

 	if (rc != -ENOTTY)
 		return rc;
-	return pci_parent_bus_reset(dev, probe);
+
+	return pci_parent_bus_reset(dev, mode);
 }

 static void pci_dev_lock(struct pci_dev *dev)
@@ -5081,17 +5103,20 @@ static void pci_dev_restore(struct pci_dev *dev)
  * @dev: device to reset
  * @probe: check if _RST method is included in the acpi_device context.
  */
-static int pci_dev_acpi_reset(struct pci_dev *dev, int probe)
+static int pci_dev_acpi_reset(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 #ifdef CONFIG_ACPI
 	acpi_handle handle = ACPI_HANDLE(&dev->dev);

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	/* Return -ENOTTY if _RST method is not included in the dev context */
 	if (!handle || !acpi_has_method(handle, "_RST"))
 		return -ENOTTY;

 	/* Return 0 for probe phase indicating that we can reset this device */
-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	/* Invoke _RST() method to perform a function level reset */
@@ -5157,7 +5182,7 @@ int __pci_reset_function_locked(struct pci_dev *dev)
 				 * other error, we're also finished: this indicates that further
 				 * reset mechanisms might be broken on the device.
 				 */
-				rc = pci_reset_fn_methods[i].reset_fn(dev, 0);
+				rc = pci_reset_fn_methods[i].reset_fn(dev, PCI_RESET_DO_RESET);
 				if (rc != -ENOTTY)
 					return rc;
 				break;
@@ -5193,7 +5218,7 @@ void pci_init_reset_methods(struct pci_dev *dev)
 	might_sleep();

 	for (i = 0; i < PCI_RESET_METHODS_NUM; i++) {
-		rc = pci_reset_fn_methods[i].reset_fn(dev, 1);
+		rc = pci_reset_fn_methods[i].reset_fn(dev, PCI_RESET_PROBE);
 		if (!rc)
 			reset_methods[i] = prio--;
 		else if (rc != -ENOTTY)
@@ -5509,21 +5534,24 @@ static void pci_slot_restore_locked(struct pci_slot *slot)
 	}
 }

-static int pci_slot_reset(struct pci_slot *slot, int probe)
+static int pci_slot_reset(struct pci_slot *slot, pci_reset_mode_t mode)
 {
 	int rc;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (!slot || !pci_slot_resetable(slot))
 		return -ENOTTY;

-	if (!probe)
+	if (mode == PCI_RESET_DO_RESET)
 		pci_slot_lock(slot);

 	might_sleep();

-	rc = pci_reset_hotplug_slot(slot->hotplug, probe);
+	rc = pci_reset_hotplug_slot(slot->hotplug, mode);

-	if (!probe)
+	if (mode == PCI_RESET_DO_RESET)
 		pci_slot_unlock(slot);

 	return rc;
@@ -5537,7 +5565,7 @@ static int pci_slot_reset(struct pci_slot *slot, int probe)
  */
 int pci_probe_reset_slot(struct pci_slot *slot)
 {
-	return pci_slot_reset(slot, 1);
+	return pci_slot_reset(slot, PCI_RESET_PROBE);
 }
 EXPORT_SYMBOL_GPL(pci_probe_reset_slot);

@@ -5560,14 +5588,14 @@ static int __pci_reset_slot(struct pci_slot *slot)
 {
 	int rc;

-	rc = pci_slot_reset(slot, 1);
+	rc = pci_slot_reset(slot, PCI_RESET_PROBE);
 	if (rc)
 		return rc;

 	if (pci_slot_trylock(slot)) {
 		pci_slot_save_and_disable_locked(slot);
 		might_sleep();
-		rc = pci_reset_hotplug_slot(slot->hotplug, 0);
+		rc = pci_reset_hotplug_slot(slot->hotplug, PCI_RESET_DO_RESET);
 		pci_slot_restore_locked(slot);
 		pci_slot_unlock(slot);
 	} else
@@ -5576,14 +5604,17 @@ static int __pci_reset_slot(struct pci_slot *slot)
 	return rc;
 }

-static int pci_bus_reset(struct pci_bus *bus, int probe)
+static int pci_bus_reset(struct pci_bus *bus, pci_reset_mode_t mode)
 {
 	int ret;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	if (!bus->self || !pci_bus_resetable(bus))
 		return -ENOTTY;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	pci_bus_lock(bus);
@@ -5622,14 +5653,14 @@ int pci_bus_error_reset(struct pci_dev *bridge)
 			goto bus_reset;

 	list_for_each_entry(slot, &bus->slots, list)
-		if (pci_slot_reset(slot, 0))
+		if (pci_slot_reset(slot, PCI_RESET_DO_RESET))
 			goto bus_reset;

 	mutex_unlock(&pci_slot_mutex);
 	return 0;
 bus_reset:
 	mutex_unlock(&pci_slot_mutex);
-	return pci_bus_reset(bridge->subordinate, 0);
+	return pci_bus_reset(bridge->subordinate, PCI_RESET_DO_RESET);
 }

 /**
@@ -5640,7 +5671,7 @@ int pci_bus_error_reset(struct pci_dev *bridge)
  */
 int pci_probe_reset_bus(struct pci_bus *bus)
 {
-	return pci_bus_reset(bus, 1);
+	return pci_bus_reset(bus, PCI_RESET_PROBE);
 }
 EXPORT_SYMBOL_GPL(pci_probe_reset_bus);

@@ -5654,7 +5685,7 @@ static int __pci_reset_bus(struct pci_bus *bus)
 {
 	int rc;

-	rc = pci_bus_reset(bus, 1);
+	rc = pci_bus_reset(bus, PCI_RESET_PROBE);
 	if (rc)
 		return rc;

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1b3ba3116..4d482965d 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -609,19 +609,19 @@ static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
 struct pci_dev_reset_methods {
 	u16 vendor;
 	u16 device;
-	int (*reset)(struct pci_dev *dev, int probe);
+	int (*reset)(struct pci_dev *dev, pci_reset_mode_t mode);
 };

 struct pci_reset_fn_method {
-	int (*reset_fn)(struct pci_dev *, int probe);
+	int (*reset_fn)(struct pci_dev *, pci_reset_mode_t mode);
 	char *name;
 };

 extern const struct pci_reset_fn_method pci_reset_fn_methods[];
 #ifdef CONFIG_PCI_QUIRKS
-int pci_dev_specific_reset(struct pci_dev *dev, int probe);
+int pci_dev_specific_reset(struct pci_dev *dev, pci_reset_mode_t mode);
 #else
-static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe)
+static inline int pci_dev_specific_reset(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	return -ENOTTY;
 }
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index f4e891bd5..1259f1cdb 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1405,7 +1405,7 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 	}

 	if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) {
-		rc = pcie_reset_flr(dev, 0);
+		rc = pcie_reset_flr(dev, PCI_RESET_DO_RESET);
 		if (!rc)
 			pci_info(dev, "has been reset\n");
 		else
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index ceec67342..5dccf14c8 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3693,7 +3693,7 @@ DECLARE_PCI_FIXUP_SUSPEND_LATE(PCI_VENDOR_ID_INTEL,
  * reset a single function if other methods (e.g. FLR, PM D0->D3) are
  * not available.
  */
-static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
+static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	/*
 	 * http://www.intel.com/content/dam/doc/datasheet/82599-10-gbe-controller-datasheet.pdf
@@ -3703,7 +3703,7 @@ static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
 	 * Thus we must call pcie_flr() directly without first checking if it is
 	 * supported.
 	 */
-	if (!probe)
+	if (mode == PCI_RESET_DO_RESET)
 		pcie_flr(dev);
 	return 0;
 }
@@ -3715,13 +3715,13 @@ static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
 #define NSDE_PWR_STATE		0xd0100
 #define IGD_OPERATION_TIMEOUT	10000     /* set timeout 10 seconds */

-static int reset_ivb_igd(struct pci_dev *dev, int probe)
+static int reset_ivb_igd(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	void __iomem *mmio_base;
 	unsigned long timeout;
 	u32 val;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	mmio_base = pci_iomap(dev, 0, 0);
@@ -3758,7 +3758,7 @@ static int reset_ivb_igd(struct pci_dev *dev, int probe)
 }

 /* Device-specific reset method for Chelsio T4-based adapters */
-static int reset_chelsio_generic_dev(struct pci_dev *dev, int probe)
+static int reset_chelsio_generic_dev(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	u16 old_command;
 	u16 msix_flags;
@@ -3774,7 +3774,7 @@ static int reset_chelsio_generic_dev(struct pci_dev *dev, int probe)
 	 * If this is the "probe" phase, return 0 indicating that we can
 	 * reset this device.
 	 */
-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	/*
@@ -3836,17 +3836,17 @@ static int reset_chelsio_generic_dev(struct pci_dev *dev, int probe)
  *    Chapter 3: NVMe control registers
  *    Chapter 7.3: Reset behavior
  */
-static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
+static int nvme_disable_and_flr(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	void __iomem *bar;
 	u16 cmd;
 	u32 cfg;

 	if (dev->class != PCI_CLASS_STORAGE_EXPRESS ||
-	    pcie_reset_flr(dev, 1) || !pci_resource_start(dev, 0))
+	    pcie_reset_flr(dev, PCI_RESET_PROBE) || !pci_resource_start(dev, 0))
 		return -ENOTTY;

-	if (probe)
+	if (mode == PCI_RESET_PROBE)
 		return 0;

 	bar = pci_iomap(dev, 0, NVME_REG_CC + sizeof(cfg));
@@ -3910,11 +3910,13 @@ static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
  * device too soon after FLR.  A 250ms delay after FLR has heuristically
  * proven to produce reliably working results for device assignment cases.
  */
-static int delay_250ms_after_flr(struct pci_dev *dev, int probe)
+static int delay_250ms_after_flr(struct pci_dev *dev, pci_reset_mode_t mode)
 {
-	int ret = pcie_reset_flr(dev, probe);
+	int ret;
+
+	ret = pcie_reset_flr(dev, mode);

-	if (probe)
+	if (ret || mode == PCI_RESET_PROBE)
 		return ret;

 	msleep(250);
@@ -3941,16 +3943,19 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
  * because when a host assigns a device to a guest VM, the host may need
  * to reset the device but probably doesn't have a driver for it.
  */
-int pci_dev_specific_reset(struct pci_dev *dev, int probe)
+int pci_dev_specific_reset(struct pci_dev *dev, pci_reset_mode_t mode)
 {
 	const struct pci_dev_reset_methods *i;

+	if (mode >= PCI_RESET_MODE_MAX)
+		return -EINVAL;
+
 	for (i = pci_dev_reset_methods; i->reset; i++) {
 		if ((i->vendor == dev->vendor ||
 		     i->vendor == (u16)PCI_ANY_ID) &&
 		    (i->device == dev->device ||
 		     i->device == (u16)PCI_ANY_ID))
-			return i->reset(dev, probe);
+			return i->reset(dev, mode);
 	}

 	return -ENOTTY;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9bec3c616..2a35ec1f3 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -51,6 +51,12 @@

 #define PCI_RESET_METHODS_NUM 6

+typedef enum pci_reset_mode {
+	PCI_RESET_DO_RESET,
+	PCI_RESET_PROBE,
+	PCI_RESET_MODE_MAX,
+} pci_reset_mode_t;
+
 /*
  * The PCI interface treats multi-function devices as independent
  * devices.  The slot/function address of each device is encoded
@@ -1222,7 +1228,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
 			     enum pci_bus_speed *speed,
 			     enum pcie_link_width *width);
 void pcie_print_link_status(struct pci_dev *dev);
-int pcie_reset_flr(struct pci_dev *dev, int probe);
+int pcie_reset_flr(struct pci_dev *dev, pci_reset_mode_t mode);
 int pcie_flr(struct pci_dev *dev);
 bool pci_reset_supported(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
diff --git a/include/linux/pci_hotplug.h b/include/linux/pci_hotplug.h
index b482e42d7..9e8da46e7 100644
--- a/include/linux/pci_hotplug.h
+++ b/include/linux/pci_hotplug.h
@@ -44,7 +44,7 @@ struct hotplug_slot_ops {
 	int (*get_attention_status)	(struct hotplug_slot *slot, u8 *value);
 	int (*get_latch_status)		(struct hotplug_slot *slot, u8 *value);
 	int (*get_adapter_status)	(struct hotplug_slot *slot, u8 *value);
-	int (*reset_slot)		(struct hotplug_slot *slot, int probe);
+	int (*reset_slot)		(struct hotplug_slot *slot, pci_reset_mode_t mode);
 };

 /**
--
2.31.1