crypto: qat - remove check after debugfs_create_dir()

Commit Message

Cabiddu, Giovanni Sept. 16, 2024, 9:42 a.m. UTC

On Sat, Sep 14, 2024 at 03:58:24PM +0200, Greg Kroah-Hartman wrote:
> On Sat, Sep 14, 2024 at 07:40:31PM +0800, Herbert Xu wrote:
> > On Sat, Sep 14, 2024 at 10:50:33AM +0200, Greg Kroah-Hartman wrote:
> > >
> > > > I think this is still buggy.  That if statement should be removed
> > > > as otherwise subsequent calls to debugfs_create_file will provide a
> > > > NULL parent dentry instead of an error parent dentry.  This causes
> > > > debugfs to do things differently.
> > > 
> > > debugfs, if something goes wrong, will return a real error, never NULL,
> > > so any return value from a call can be passed back in.
> > 
> > Right, that's why we should remove the if statement so that the
> > error is saved and can then be passed back into the next debugfs
> > call.
> > 
> > With the error-checking if statement there, the error is discarded
> > and the next debugfs call from this driver will simply get a NULL
> > parent dentry.
> 
> Sorry, but yes, we are in agreement here, sorry, been reviewing a lot of
> these "clean up" fixes that were wrong and got them confused.
Thanks Herbert and Greg for following up on this.
Here is a fix.

---8<---
The debugfs functions are guaranteed to return a valid error code
instead of NULL upon failure. Consequently, the driver can directly
propagate any error returned without additional checks.

Remove the unnecessary `if` statement after debugfs_create_dir(). If
this function fails, the error code is stored in accel_dev->debugfs_dir
and utilized in subsequent debugfs calls.

Additionally, since accel_dev->debugfs_dir is assured to be non-NULL,
remove the superfluous NULL pointer checks within the adf_dbgfs_add()
and adf_dbgfs_rm().

Fixes: 9260db6640a6 ("crypto: qat - move dbgfs init to separate file")
Signed-off-by: Giovanni Cabiddu <[e-mail]>
---
 drivers/crypto/intel/qat/qat_common/adf_dbgfs.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

Comments

Herbert Xu Oct. 5, 2024, 5:32 a.m. UTC | #1

On Mon, Sep 16, 2024 at 10:42:51AM +0100, Cabiddu, Giovanni wrote:
> The debugfs functions are guaranteed to return a valid error code
> instead of NULL upon failure. Consequently, the driver can directly
> propagate any error returned without additional checks.
> 
> Remove the unnecessary `if` statement after debugfs_create_dir(). If
> this function fails, the error code is stored in accel_dev->debugfs_dir
> and utilized in subsequent debugfs calls.
> 
> Additionally, since accel_dev->debugfs_dir is assured to be non-NULL,
> remove the superfluous NULL pointer checks within the adf_dbgfs_add()
> and adf_dbgfs_rm().
> 
> Fixes: 9260db6640a6 ("crypto: qat - move dbgfs init to separate file")
> Signed-off-by: Giovanni Cabiddu <[e-mail]>
> ---
>  drivers/crypto/intel/qat/qat_common/adf_dbgfs.c | 13 +------------
>  1 file changed, 1 insertion(+), 12 deletions(-)

Patch applied.  Thanks.

Patch

diff --git a/drivers/crypto/intel/qat/qat_common/adf_dbgfs.c b/drivers/crypto/intel/qat/qat_common/adf_dbgfs.c
index c42f5c25aabd..4c11ad1ebcf0 100644
--- a/drivers/crypto/intel/qat/qat_common/adf_dbgfs.c
+++ b/drivers/crypto/intel/qat/qat_common/adf_dbgfs.c
@@ -22,18 +22,13 @@ 
 void adf_dbgfs_init(struct adf_accel_dev *accel_dev)
 {
 	char name[ADF_DEVICE_NAME_LENGTH];
-	void *ret;
 
 	/* Create dev top level debugfs entry */
 	snprintf(name, sizeof(name), "%s%s_%s", ADF_DEVICE_NAME_PREFIX,
 		 accel_dev->hw_device->dev_class->name,
 		 pci_name(accel_dev->accel_pci_dev.pci_dev));
 
-	ret = debugfs_create_dir(name, NULL);
-	if (IS_ERR_OR_NULL(ret))
-		return;
-
-	accel_dev->debugfs_dir = ret;
+	accel_dev->debugfs_dir = debugfs_create_dir(name, NULL);
 
 	adf_cfg_dev_dbgfs_add(accel_dev);
 }
@@ -59,9 +54,6 @@  EXPORT_SYMBOL_GPL(adf_dbgfs_exit);
  */
 void adf_dbgfs_add(struct adf_accel_dev *accel_dev)
 {
-	if (!accel_dev->debugfs_dir)
-		return;
-
 	if (!accel_dev->is_vf) {
 		adf_fw_counters_dbgfs_add(accel_dev);
 		adf_heartbeat_dbgfs_add(accel_dev);
@@ -77,9 +69,6 @@  void adf_dbgfs_add(struct adf_accel_dev *accel_dev)
  */
 void adf_dbgfs_rm(struct adf_accel_dev *accel_dev)
 {
-	if (!accel_dev->debugfs_dir)
-		return;
-
 	if (!accel_dev->is_vf) {
 		adf_tl_dbgfs_rm(accel_dev);
 		adf_cnv_dbgfs_rm(accel_dev);