[cip-dev] [RFC PATCH 4.19.y-cip 30/50] PCI: endpoint: Fix clearing start entry in configfs

Lad Prabhakar
2020-10-12T14:21:04Z

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From: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>

commit f58d5f53c89479c12ad719c1960176442add5aaa upstream.

After an endpoint is started through configfs, if 0 is written to the
configfs entry 'start', the controller stops but the epc_group->start
value remains 1.

A subsequent unlinking of the function from the controller would trigger
a spurious WARN_ON_ONCE() in pci_epc_epf_unlink() despite right
behavior.

Fix it by setting epc_group->start = 0 when a controller is stopped
using configfs.

Fixes: d74679911610 ("PCI: endpoint: Introduce configfs entry for configuring EP functions")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
drivers/pci/endpoint/pci-ep-cfs.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index e7e8367eead1..55edce50be96 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -57,6 +57,7 @@ static ssize_t pci_epc_start_store(struct config_item *item, const char *page,

if (!start) {
pci_epc_stop(epc);
+ epc_group->start = 0;
return len;
}

--
2.17.1

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