linux-kernel - [PATCH 1/2] fpga: altera-cvp: fix probing for multiple FPGAs on the bus

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Message-Id: <1543253728-26542-2-git-send-email-atull@kernel.org>
Date:   Mon, 26 Nov 2018 11:35:27 -0600
From:   Alan Tull <atull@...nel.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Moritz Fischer <mdf@...nel.org>, Alan Tull <atull@...nel.org>,
        linux-kernel@...r.kernel.org, linux-fpga@...r.kernel.org,
        Anatolij Gustschin <agust@...x.de>
Subject: [PATCH 1/2] fpga: altera-cvp: fix probing for multiple FPGAs on the bus

From: Anatolij Gustschin <agust@...x.de>

Currently registering CvP managers works only for first probed CvP
device, for all other devices it is refused due to duplicated chkcfg
sysfs entry:

fpga_manager fpga3: Altera CvP FPGA Manager @0000:0c:00.0 registered
sysfs: cannot create duplicate filename '/bus/pci/drivers/altera-cvp/chkcfg'
CPU: 0 PID: 3808 Comm: bash Tainted: G           O      4.19.0-custom+ #5
Call Trace:
  dump_stack+0x46/0x5b
  sysfs_warn_dup+0x53/0x60
  sysfs_add_file_mode_ns+0x16d/0x180
  sysfs_create_file_ns+0x51/0x60
  altera_cvp_probe+0x16f/0x2a0 [altera_cvp]
  local_pci_probe+0x3f/0xa0
  ? pci_match_device+0xb1/0xf0
  pci_device_probe+0x116/0x170
  really_probe+0x21b/0x2c0
  driver_probe_device+0x4b/0xe0
  bind_store+0xcb/0x130
  kernfs_fop_write+0xfd/0x180
  __vfs_write+0x21/0x150
  ? selinux_file_permission+0xdc/0x130
  vfs_write+0xa8/0x1a0
  ? find_vma+0xd/0x60
  ksys_write+0x3d/0x90
  do_syscall_64+0x44/0xf0
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ...
 altera-cvp 0000:0c:00.0: Can't create sysfs chkcfg file
 fpga_manager fpga3: fpga_mgr_unregister Altera CvP FPGA Manager @0000:0c:00.0

Move chkcfg creation to module init as suggested by Alan.

Signed-off-by: Anatolij Gustschin <agust@...x.de>
Acked-by: Alan Tull <atull@...nel.org>
---
 drivers/fpga/altera-cvp.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
index 7395085..35c3aa5 100644
--- a/drivers/fpga/altera-cvp.c
+++ b/drivers/fpga/altera-cvp.c
@@ -475,14 +475,6 @@ static int altera_cvp_probe(struct pci_dev *pdev,
 	if (ret)
 		goto err_unmap;
 
-	ret = driver_create_file(&altera_cvp_driver.driver,
-				 &driver_attr_chkcfg);
-	if (ret) {
-		dev_err(&pdev->dev, "Can't create sysfs chkcfg file\n");
-		fpga_mgr_unregister(mgr);
-		goto err_unmap;
-	}
-
 	return 0;
 
 err_unmap:
@@ -501,7 +493,6 @@ static void altera_cvp_remove(struct pci_dev *pdev)
 	struct altera_cvp_conf *conf = mgr->priv;
 	u16 cmd;
 
-	driver_remove_file(&altera_cvp_driver.driver, &driver_attr_chkcfg);
 	fpga_mgr_unregister(mgr);
 	if (conf->map)
 		pci_iounmap(pdev, conf->map);
@@ -511,7 +502,30 @@ static void altera_cvp_remove(struct pci_dev *pdev)
 	pci_write_config_word(pdev, PCI_COMMAND, cmd);
 }
 
-module_pci_driver(altera_cvp_driver);
+static int __init altera_cvp_init(void)
+{
+	int ret;
+
+	ret = pci_register_driver(&altera_cvp_driver);
+	if (ret)
+		return ret;
+
+	ret = driver_create_file(&altera_cvp_driver.driver,
+				 &driver_attr_chkcfg);
+	if (ret)
+		pr_warn("Can't create sysfs chkcfg file\n");
+
+	return 0;
+}
+
+static void __exit altera_cvp_exit(void)
+{
+	driver_remove_file(&altera_cvp_driver.driver, &driver_attr_chkcfg);
+	pci_unregister_driver(&altera_cvp_driver);
+}
+
+module_init(altera_cvp_init);
+module_exit(altera_cvp_exit);
 
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Anatolij Gustschin <agust@...x.de>");
-- 
2.7.4