linux-kernel - [PATCH] PCI: designware-ep: use ffz() instead of find_first_zero

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Message-Id: <20171116183438.12613-1-niklas.cassel@axis.com>
Date:   Thu, 16 Nov 2017 19:34:38 +0100
From:   Niklas Cassel <niklas.cassel@...s.com>
To:     Jingoo Han <jingoohan1@...il.com>,
        Joao Pinto <Joao.Pinto@...opsys.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     Niklas Cassel <niklass@...s.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] PCI: designware-ep: use ffz() instead of find_first_zero_bit()

find_first_zero_bit()'s parameter 'size' is defined in bits,
not in bytes.

find_first_zero_bit() was called with bytes rather than bits,
which thus defined a too low upper limit, causing
dw_pcie_ep_inbound_atu() to assign iatu index #4 to both bar 4
and bar 5, which made bar 5 overwrite the settings set by bar 4.

./pcitest.sh
BAR tests
BAR0:		OKAY
BAR1:		OKAY
BAR2:		OKAY
BAR3:		OKAY
BAR4:		NOT OKAY
BAR5:		OKAY

Fix this by using replacing find_first_zero_bit() with ffz(),
since ffz() only works on a single 'unsigned long' and therefore
does not need a size argument.

Signed-off-by: Niklas Cassel <niklas.cassel@...s.com>
---
 drivers/pci/dwc/pcie-designware-ep.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index d53d5f168363..ab9a9e160daf 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -70,8 +70,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
 	u32 free_win;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	free_win = find_first_zero_bit(&ep->ib_window_map,
-				       sizeof(ep->ib_window_map));
+	free_win = ffz(ep->ib_window_map);
 	if (free_win >= ep->num_ib_windows) {
 		dev_err(pci->dev, "no free inbound window\n");
 		return -EINVAL;
@@ -96,8 +95,7 @@ static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, phys_addr_t phys_addr,
 	u32 free_win;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	free_win = find_first_zero_bit(&ep->ob_window_map,
-				       sizeof(ep->ob_window_map));
+	free_win = ffz(ep->ob_window_map);
 	if (free_win >= ep->num_ob_windows) {
 		dev_err(pci->dev, "no free outbound window\n");
 		return -EINVAL;
-- 
2.14.2