PCI: endpoint: Fix find_first_zero_bit() usage

BugLink: http://bugs.launchpad.net/bugs/1758886
[ Upstream commit 35ad61921f495ee14915d185de79478c1737b4da ]

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

Calling find_first_zero_bit() with the wrong size unit
will lead to insidious bugs.

Fix this by calling find_first_zero_bit() with size BITS_PER_LONG,
rather than sizeof() and add missing find_first_zero_bit() return
handling.

Fixes: d74679911610 ("PCI: endpoint: Introduce configfs entry for configuring EP functions")
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index 4f74386c1ced797c8fa98e0faae671adacfa2680..5508cd32afcd1d77351dbf82ab60fb7611cf1acb 100644 (file)
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -109,7 +109,10 @@ static int pci_epc_epf_link(struct config_item *epc_item,
                goto err_add_epf;
 
        func_no = find_first_zero_bit(&epc_group->function_num_map,
-                                     sizeof(epc_group->function_num_map));
+                                     BITS_PER_LONG);
+       if (func_no >= BITS_PER_LONG)
+               return -EINVAL;
+
        set_bit(func_no, &epc_group->function_num_map);
        epf->func_no = func_no;