[PATCH 6.12 02/35] PCI: endpoint: pci-epf-vntb: Remove duplicate resource teardown

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Koichiro Den <den@valinux.co.jp>

[ Upstream commit 0da63230d3ec1ec5fcc443a2314233e95bfece54 ]

epf_ntb_epc_destroy() duplicates the teardown that the caller is
supposed to perform later. This leads to an oops when .allow_link fails
or when .drop_link is performed. The following is an example oops of the
former case:

  Unable to handle kernel paging request at virtual address dead000000000108
  [...]
  [dead000000000108] address between user and kernel address ranges
  Internal error: Oops: 0000000096000044 [#1]  SMP
  [...]
  Call trace:
   pci_epc_remove_epf+0x78/0xe0 (P)
   pci_primary_epc_epf_link+0x88/0xa8
   configfs_symlink+0x1f4/0x5a0
   vfs_symlink+0x134/0x1d8
   do_symlinkat+0x88/0x138
   __arm64_sys_symlinkat+0x74/0xe0
  [...]

Remove the helper, and drop pci_epc_put(). EPC device refcounting is
tied to the configfs EPC group lifetime, and pci_epc_put() in the
.drop_link path is sufficient.

Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260226084142.2226875-2-den@valinux.co.jp
[ adjusted context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/endpoint/functions/pci-epf-vntb.c | 18 +-----------------
 1 file changed, 1 insertion(+), 17 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index be2277cb9b637..6875af691b2de 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -662,18 +662,6 @@ static void epf_ntb_mw_bar_clear(struct epf_ntb *ntb, int num_mws)
 	}
 }
 
-/**
- * epf_ntb_epc_destroy() - Cleanup NTB EPC interface
- * @ntb: NTB device that facilitates communication between HOST and VHOST
- *
- * Wrapper for epf_ntb_epc_destroy_interface() to cleanup all the NTB interfaces
- */
-static void epf_ntb_epc_destroy(struct epf_ntb *ntb)
-{
-	pci_epc_remove_epf(ntb->epf->epc, ntb->epf, 0);
-	pci_epc_put(ntb->epf->epc);
-}
-
 /**
  * epf_ntb_init_epc_bar() - Identify BARs to be used for each of the NTB
  * constructs (scratchpad region, doorbell, memorywindow)
@@ -1315,7 +1303,7 @@ static int epf_ntb_bind(struct pci_epf *epf)
 	ret = epf_ntb_init_epc_bar(ntb);
 	if (ret) {
 		dev_err(dev, "Failed to create NTB EPC\n");
-		goto err_bar_init;
+		return ret;
 	}
 
 	ret = epf_ntb_config_spad_bar_alloc(ntb);
@@ -1355,9 +1343,6 @@ static int epf_ntb_bind(struct pci_epf *epf)
 err_bar_alloc:
 	epf_ntb_config_spad_bar_free(ntb);
 
-err_bar_init:
-	epf_ntb_epc_destroy(ntb);
-
 	return ret;
 }
 
@@ -1373,7 +1358,6 @@ static void epf_ntb_unbind(struct pci_epf *epf)
 
 	epf_ntb_epc_cleanup(ntb);
 	epf_ntb_config_spad_bar_free(ntb);
-	epf_ntb_epc_destroy(ntb);
 
 	pci_unregister_driver(&vntb_pci_driver);
 }
-- 
2.53.0