diff mbox series

[net,v2,3/5] ibmvnic: Handle DMA unmapping of login buffs in release functions

Message ID 20230809221038.51296-3-nnac123@linux.ibm.com (mailing list archive)
State Accepted
Commit d78a671eb8996af19d6311ecdee9790d2fa479f0
Delegated to: Netdev Maintainers
Headers show
Series [net,v2,1/5] ibmvnic: Enforce stronger sanity checks on login response | expand

Checks

Context Check Description
netdev/series_format warning Series does not have a cover letter
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers fail 1 blamed authors not CCed: davem@davemloft.net; 9 maintainers not CCed: mpe@ellerman.id.au kuba@kernel.org npiggin@gmail.com christophe.leroy@csgroup.eu davem@davemloft.net ricklind@linux.ibm.com pabeni@redhat.com edumazet@google.com linuxppc-dev@lists.ozlabs.org
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 33 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Nick Child Aug. 9, 2023, 10:10 p.m. UTC
Rather than leaving the DMA unmapping of the login buffers to the
login response handler, move this work into the login release functions.
Previously, these functions were only used for freeing the allocated
buffers. This could lead to issues if there are more than one
outstanding login buffer requests, which is possible if a login request
times out.

If a login request times out, then there is another call to send login.
The send login function makes a call to the login buffer release
function. In the past, this freed the buffers but did not DMA unmap.
Therefore, the VIOS could still write to the old login (now freed)
buffer. It is for this reason that it is a good idea to leave the DMA
unmap call to the login buffers release function.

Since the login buffer release functions now handle DMA unmapping,
remove the duplicate DMA unmapping in handle_login_rsp().

Fixes: dff515a3e71d ("ibmvnic: Harden device login requests")
Signed-off-by: Nick Child <nnac123@linux.ibm.com>
Reviewed-by: Simon Horman <horms@kernel.org>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 668c67556190..77b0a744fa88 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1588,12 +1588,22 @@  static int ibmvnic_login(struct net_device *netdev)
 
 static void release_login_buffer(struct ibmvnic_adapter *adapter)
 {
+	if (!adapter->login_buf)
+		return;
+
+	dma_unmap_single(&adapter->vdev->dev, adapter->login_buf_token,
+			 adapter->login_buf_sz, DMA_TO_DEVICE);
 	kfree(adapter->login_buf);
 	adapter->login_buf = NULL;
 }
 
 static void release_login_rsp_buffer(struct ibmvnic_adapter *adapter)
 {
+	if (!adapter->login_rsp_buf)
+		return;
+
+	dma_unmap_single(&adapter->vdev->dev, adapter->login_rsp_buf_token,
+			 adapter->login_rsp_buf_sz, DMA_FROM_DEVICE);
 	kfree(adapter->login_rsp_buf);
 	adapter->login_rsp_buf = NULL;
 }
@@ -5411,11 +5421,6 @@  static int handle_login_rsp(union ibmvnic_crq *login_rsp_crq,
 	}
 	adapter->login_pending = false;
 
-	dma_unmap_single(dev, adapter->login_buf_token, adapter->login_buf_sz,
-			 DMA_TO_DEVICE);
-	dma_unmap_single(dev, adapter->login_rsp_buf_token,
-			 adapter->login_rsp_buf_sz, DMA_FROM_DEVICE);
-
 	/* If the number of queues requested can't be allocated by the
 	 * server, the login response will return with code 1. We will need
 	 * to resend the login buffer with fewer queues requested.