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Subject[PATCH 5.5 397/399] s390/pci: Recover handle in clp_set_pci_fn()
Date
From: Niklas Schnelle <schnelle@linux.ibm.com>

[ Upstream commit 17cdec960cf776b20b1fb08c622221babe591d51 ]

When we try to recover a PCI function using

echo 1 > /sys/bus/pci/devices/<id>/recover

or manually with

echo 1 > /sys/bus/pci/devices/<id>/remove
echo 0 > /sys/bus/pci/slots/<slot>/power
echo 1 > /sys/bus/pci/slots/<slot>/power

clp_disable_fn() / clp_enable_fn() call clp_set_pci_fn() to first
disable and then reenable the function.

When the function is already in the requested state we may be left with
an invalid function handle.

To get a new valid handle we do a clp_list_pci() call. For this we need
both the function ID and function handle in clp_set_pci_fn() so pass the
zdev and get both.

To simplify things also pull setting the refreshed function handle into
clp_set_pci_fn()

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/include/asm/pci.h | 2 +-
arch/s390/pci/pci.c | 2 +-
arch/s390/pci/pci_clp.c | 48 ++++++++++++++++++++++---------------
3 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 3a06c264ea533..b05187ce5dbdc 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -180,7 +180,7 @@ void zpci_remove_reserved_devices(void);
/* CLP */
int clp_scan_pci_devices(void);
int clp_rescan_pci_devices(void);
-int clp_rescan_pci_devices_simple(void);
+int clp_rescan_pci_devices_simple(u32 *fid);
int clp_add_pci_device(u32, u32, int);
int clp_enable_fh(struct zpci_dev *, u8);
int clp_disable_fh(struct zpci_dev *);
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 8e872951c07ba..bc61ea18e88d9 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -939,5 +939,5 @@ subsys_initcall_sync(pci_base_init);
void zpci_rescan(void)
{
if (zpci_is_enabled())
- clp_rescan_pci_devices_simple();
+ clp_rescan_pci_devices_simple(NULL);
}
diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c
index 4c613e569fe08..0d3d8f170ea42 100644
--- a/arch/s390/pci/pci_clp.c
+++ b/arch/s390/pci/pci_clp.c
@@ -240,12 +240,14 @@ error:
}

/*
- * Enable/Disable a given PCI function defined by its function handle.
+ * Enable/Disable a given PCI function and update its function handle if
+ * necessary
*/
-static int clp_set_pci_fn(u32 *fh, u8 nr_dma_as, u8 command)
+static int clp_set_pci_fn(struct zpci_dev *zdev, u8 nr_dma_as, u8 command)
{
struct clp_req_rsp_set_pci *rrb;
int rc, retries = 100;
+ u32 fid = zdev->fid;

rrb = clp_alloc_block(GFP_KERNEL);
if (!rrb)
@@ -256,7 +258,7 @@ static int clp_set_pci_fn(u32 *fh, u8 nr_dma_as, u8 command)
rrb->request.hdr.len = sizeof(rrb->request);
rrb->request.hdr.cmd = CLP_SET_PCI_FN;
rrb->response.hdr.len = sizeof(rrb->response);
- rrb->request.fh = *fh;
+ rrb->request.fh = zdev->fh;
rrb->request.oc = command;
rrb->request.ndas = nr_dma_as;

@@ -269,12 +271,17 @@ static int clp_set_pci_fn(u32 *fh, u8 nr_dma_as, u8 command)
}
} while (rrb->response.hdr.rsp == CLP_RC_SETPCIFN_BUSY);

- if (!rc && rrb->response.hdr.rsp == CLP_RC_OK)
- *fh = rrb->response.fh;
- else {
+ if (rc || rrb->response.hdr.rsp != CLP_RC_OK) {
zpci_err("Set PCI FN:\n");
zpci_err_clp(rrb->response.hdr.rsp, rc);
- rc = -EIO;
+ }
+
+ if (!rc && rrb->response.hdr.rsp == CLP_RC_OK) {
+ zdev->fh = rrb->response.fh;
+ } else if (!rc && rrb->response.hdr.rsp == CLP_RC_SETPCIFN_ALRDY &&
+ rrb->response.fh == 0) {
+ /* Function is already in desired state - update handle */
+ rc = clp_rescan_pci_devices_simple(&fid);
}
clp_free_block(rrb);
return rc;
@@ -282,18 +289,17 @@ static int clp_set_pci_fn(u32 *fh, u8 nr_dma_as, u8 command)

int clp_enable_fh(struct zpci_dev *zdev, u8 nr_dma_as)
{
- u32 fh = zdev->fh;
int rc;

- rc = clp_set_pci_fn(&fh, nr_dma_as, CLP_SET_ENABLE_PCI_FN);
- zpci_dbg(3, "ena fid:%x, fh:%x, rc:%d\n", zdev->fid, fh, rc);
+ rc = clp_set_pci_fn(zdev, nr_dma_as, CLP_SET_ENABLE_PCI_FN);
+ zpci_dbg(3, "ena fid:%x, fh:%x, rc:%d\n", zdev->fid, zdev->fh, rc);
if (rc)
goto out;

- zdev->fh = fh;
if (zpci_use_mio(zdev)) {
- rc = clp_set_pci_fn(&fh, nr_dma_as, CLP_SET_ENABLE_MIO);
- zpci_dbg(3, "ena mio fid:%x, fh:%x, rc:%d\n", zdev->fid, fh, rc);
+ rc = clp_set_pci_fn(zdev, nr_dma_as, CLP_SET_ENABLE_MIO);
+ zpci_dbg(3, "ena mio fid:%x, fh:%x, rc:%d\n",
+ zdev->fid, zdev->fh, rc);
if (rc)
clp_disable_fh(zdev);
}
@@ -309,11 +315,8 @@ int clp_disable_fh(struct zpci_dev *zdev)
if (!zdev_enabled(zdev))
return 0;

- rc = clp_set_pci_fn(&fh, 0, CLP_SET_DISABLE_PCI_FN);
+ rc = clp_set_pci_fn(zdev, 0, CLP_SET_DISABLE_PCI_FN);
zpci_dbg(3, "dis fid:%x, fh:%x, rc:%d\n", zdev->fid, fh, rc);
- if (!rc)
- zdev->fh = fh;
-
return rc;
}

@@ -370,10 +373,14 @@ static void __clp_add(struct clp_fh_list_entry *entry, void *data)
static void __clp_update(struct clp_fh_list_entry *entry, void *data)
{
struct zpci_dev *zdev;
+ u32 *fid = data;

if (!entry->vendor_id)
return;

+ if (fid && *fid != entry->fid)
+ return;
+
zdev = get_zdev_by_fid(entry->fid);
if (!zdev)
return;
@@ -413,7 +420,10 @@ int clp_rescan_pci_devices(void)
return rc;
}

-int clp_rescan_pci_devices_simple(void)
+/* Rescan PCI functions and refresh function handles. If fid is non-NULL only
+ * refresh the handle of the function matching @fid
+ */
+int clp_rescan_pci_devices_simple(u32 *fid)
{
struct clp_req_rsp_list_pci *rrb;
int rc;
@@ -422,7 +432,7 @@ int clp_rescan_pci_devices_simple(void)
if (!rrb)
return -ENOMEM;

- rc = clp_list_pci(rrb, NULL, __clp_update);
+ rc = clp_list_pci(rrb, fid, __clp_update);

clp_free_block(rrb);
return rc;
--
2.20.1


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