[PATCH 5.10 013/157] s390/pci: refactor zpci_create_device()

Greg Kroah-Hartman
2021-03-22T12:40:52Z

From: Niklas Schnelle <schnelle@linux.ibm.com>

commit ba764dd703feacb5a9c410d191af1b6cfbe96845 upstream.

Currently zpci_create_device() is only called in clp_add_pci_device()
which allocates the memory for the struct zpci_dev being created. There
is little separation of concerns as only both functions together can
create a zpci_dev and the only CLP specific code in
clp_add_pci_device() is a call to clp_query_pci_fn().

Improve this by removing clp_add_pci_device() and refactor
zpci_create_device() such that it alone creates and initializes the
zpci_dev given the FID and Function Handle. For this we need to make
clp_query_pci_fn() non-static. While at it remove the function handle
parameter since we can just take that from the zpci_dev. Also move
adding to the zpci_list to after the zdev has been fully created which
eliminates a window where a partially initialized zdev can be found by
get_zdev_by_fid().

Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/s390/include/asm/pci.h | 4 +--
arch/s390/pci/pci.c | 57 +++++++++++++++++++++++++++++++-------------
arch/s390/pci/pci_clp.c | 40 ++----------------------------
arch/s390/pci/pci_event.c | 4 +--
4 files changed, 48 insertions(+), 57 deletions(-)

--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -201,7 +201,7 @@ extern unsigned int s390_pci_no_rid;
Prototypes
----------------------------------------------------------------------------- */
/* Base stuff */
-int zpci_create_device(struct zpci_dev *);
+int zpci_create_device(u32 fid, u32 fh, enum zpci_state state);
void zpci_remove_device(struct zpci_dev *zdev);
int zpci_enable_device(struct zpci_dev *);
int zpci_disable_device(struct zpci_dev *);
@@ -212,7 +212,7 @@ void zpci_remove_reserved_devices(void);
/* CLP */
int clp_setup_writeback_mio(void);
int clp_scan_pci_devices(void);
-int clp_add_pci_device(u32, u32, int);
+int clp_query_pci_fn(struct zpci_dev *zdev);
int clp_enable_fh(struct zpci_dev *, u8);
int clp_disable_fh(struct zpci_dev *);
int clp_get_state(u32 fid, enum zpci_state *state);
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -695,43 +695,68 @@ void zpci_remove_device(struct zpci_dev
}
}

-int zpci_create_device(struct zpci_dev *zdev)
+/**
+ * zpci_create_device() - Create a new zpci_dev and add it to the zbus
+ * @fid: Function ID of the device to be created
+ * @fh: Current Function Handle of the device to be created
+ * @state: Initial state after creation either Standby or Configured
+ *
+ * Creates a new zpci device and adds it to its, possibly newly created, zbus
+ * as well as zpci_list.
+ *
+ * Returns: 0 on success, an error value otherwise
+ */
+int zpci_create_device(u32 fid, u32 fh, enum zpci_state state)
{
+ struct zpci_dev *zdev;
int rc;

- kref_init(&zdev->kref);
+ zpci_dbg(3, "add fid:%x, fh:%x, c:%d\n", fid, fh, state);
+ zdev = kzalloc(sizeof(*zdev), GFP_KERNEL);
+ if (!zdev)
+ return -ENOMEM;
+
+ /* FID and Function Handle are the static/dynamic identifiers */
+ zdev->fid = fid;
+ zdev->fh = fh;

- spin_lock(&zpci_list_lock);
- list_add_tail(&zdev->entry, &zpci_list);
- spin_unlock(&zpci_list_lock);
+ /* Query function properties and update zdev */
+ rc = clp_query_pci_fn(zdev);
+ if (rc)
+ goto error;
+ zdev->state = state;
+
+ kref_init(&zdev->kref);
+ mutex_init(&zdev->lock);

rc = zpci_init_iommu(zdev);
if (rc)
- goto out;
+ goto error;

- mutex_init(&zdev->lock);
if (zdev->state == ZPCI_FN_STATE_CONFIGURED) {
rc = zpci_enable_device(zdev);
if (rc)
- goto out_destroy_iommu;
+ goto error_destroy_iommu;
}

rc = zpci_bus_device_register(zdev, &pci_root_ops);
if (rc)
- goto out_disable;
+ goto error_disable;
+
+ spin_lock(&zpci_list_lock);
+ list_add_tail(&zdev->entry, &zpci_list);
+ spin_unlock(&zpci_list_lock);

return 0;

-out_disable:
+error_disable:
if (zdev->state == ZPCI_FN_STATE_ONLINE)
zpci_disable_device(zdev);
-
-out_destroy_iommu:
+error_destroy_iommu:
zpci_destroy_iommu(zdev);
-out:
- spin_lock(&zpci_list_lock);
- list_del(&zdev->entry);
- spin_unlock(&zpci_list_lock);
+error:
+ zpci_dbg(0, "add fid:%x, rc:%d\n", fid, rc);
+ kfree(zdev);
return rc;
}

--- a/arch/s390/pci/pci_clp.c
+++ b/arch/s390/pci/pci_clp.c
@@ -181,7 +181,7 @@ static int clp_store_query_pci_fn(struct
return 0;
}

-static int clp_query_pci_fn(struct zpci_dev *zdev, u32 fh)
+int clp_query_pci_fn(struct zpci_dev *zdev)
{
struct clp_req_rsp_query_pci *rrb;
int rc;
@@ -194,7 +194,7 @@ static int clp_query_pci_fn(struct zpci_
rrb->request.hdr.len = sizeof(rrb->request);
rrb->request.hdr.cmd = CLP_QUERY_PCI_FN;
rrb->response.hdr.len = sizeof(rrb->response);
- rrb->request.fh = fh;
+ rrb->request.fh = zdev->fh;

rc = clp_req(rrb, CLP_LPS_PCI);
if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
@@ -212,40 +212,6 @@ out:
return rc;
}

-int clp_add_pci_device(u32 fid, u32 fh, int configured)
-{
- struct zpci_dev *zdev;
- int rc = -ENOMEM;
-
- zpci_dbg(3, "add fid:%x, fh:%x, c:%d\n", fid, fh, configured);
- zdev = kzalloc(sizeof(*zdev), GFP_KERNEL);
- if (!zdev)
- goto error;
-
- zdev->fh = fh;
- zdev->fid = fid;
-
- /* Query function properties and update zdev */
- rc = clp_query_pci_fn(zdev, fh);
- if (rc)
- goto error;
-
- if (configured)
- zdev->state = ZPCI_FN_STATE_CONFIGURED;
- else
- zdev->state = ZPCI_FN_STATE_STANDBY;
-
- rc = zpci_create_device(zdev);
- if (rc)
- goto error;
- return 0;
-
-error:
- zpci_dbg(0, "add fid:%x, rc:%d\n", fid, rc);
- kfree(zdev);
- return rc;
-}
-
static int clp_refresh_fh(u32 fid);
/*
* Enable/Disable a given PCI function and update its function handle if
@@ -408,7 +374,7 @@ static void __clp_add(struct clp_fh_list

zdev = get_zdev_by_fid(entry->fid);
if (!zdev)
- clp_add_pci_device(entry->fid, entry->fh, entry->config_state);
+ zpci_create_device(entry->fid, entry->fh, entry->config_state);
}

int clp_scan_pci_devices(void)
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -89,7 +89,7 @@ static void __zpci_event_availability(st
switch (ccdf->pec) {
case 0x0301: /* Reserved|Standby -> Configured */
if (!zdev) {
- ret = clp_add_pci_device(ccdf->fid, ccdf->fh, 1);
+ zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED);
break;
}
/* the configuration request may be stale */
@@ -116,7 +116,7 @@ static void __zpci_event_availability(st
break;
case 0x0302: /* Reserved -> Standby */
if (!zdev) {
- clp_add_pci_device(ccdf->fid, ccdf->fh, 0);
+ zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY);
break;
}
zdev->fh = ccdf->fh;