linux-kernel - Re: [PATCH v2] cxl/memdev: automate cleanup with _

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <aFrBeCn-j_AB1yzv@rric.localdomain>
Date: Tue, 24 Jun 2025 17:17:12 +0200
From: Robert Richter <rrichter@....com>
To: Pranav Tyagi <pranav.tyagi03@...il.com>
Cc: dave@...olabs.net, jonathan.cameron@...wei.com, dave.jiang@...el.com,
	alison.schofield@...el.com, vishal.l.verma@...el.com,
	ira.weiny@...el.com, dan.j.williams@...el.com,
	linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org,
	ming.li@...omail.com, peterz@...radead.org,
	skhan@...uxfoundation.org, linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH v2] cxl/memdev: automate cleanup with __free()

On 23.06.25 14:08:41, Pranav Tyagi wrote:
> Use the scope based resource management (defined in linux/cleanup.h) to
> automate the lifetime control of struct cxl_mbox_transfer_fw. This
> eliminates explicit kfree() calls and makes the code more robust and
> maintainable in presence of early returns.
> 
> Signed-off-by: Pranav Tyagi <pranav.tyagi03@...il.com>
> ---
>  drivers/cxl/core/memdev.c | 21 ++++++++-------------
>  1 file changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index f88a13adf7fa..38f4449f9740 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -7,6 +7,7 @@
>  #include <linux/slab.h>
>  #include <linux/idr.h>
>  #include <linux/pci.h>
> +#include <linux/cleanup.h>
>  #include <cxlmem.h>
>  #include "trace.h"
>  #include "core.h"
> @@ -802,11 +803,10 @@ static int cxl_mem_activate_fw(struct cxl_memdev_state *mds, int slot)
>  static int cxl_mem_abort_fw_xfer(struct cxl_memdev_state *mds)
>  {
>  	struct cxl_mailbox *cxl_mbox = &mds->cxlds.cxl_mbox;
> -	struct cxl_mbox_transfer_fw *transfer;
>  	struct cxl_mbox_cmd mbox_cmd;
> -	int rc;
> -
> -	transfer = kzalloc(struct_size(transfer, data, 0), GFP_KERNEL);
> +	
> +	struct cxl_mbox_transfer_fw *transfer __free(kfree) =
> +		kzalloc(struct_size(transfer, data, 0), GFP_KERNEL);

I don't see a reason for __free() here as there are no early exits.

>  	if (!transfer)
>  		return -ENOMEM;
>  
> @@ -821,9 +821,7 @@ static int cxl_mem_abort_fw_xfer(struct cxl_memdev_state *mds)
>  
>  	transfer->action = CXL_FW_TRANSFER_ACTION_ABORT;
>  
> -	rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
> -	kfree(transfer);
> -	return rc;
> +	return cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
>  }
>  
>  static void cxl_fw_cleanup(struct fw_upload *fwl)
> @@ -880,7 +878,7 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>  	struct cxl_dev_state *cxlds = &mds->cxlds;
>  	struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
>  	struct cxl_memdev *cxlmd = cxlds->cxlmd;
> -	struct cxl_mbox_transfer_fw *transfer;
> +	struct cxl_mbox_transfer_fw *transfer __free(kfree);

Jonathan already catched this.

>  	struct cxl_mbox_cmd mbox_cmd;
>  	u32 cur_size, remaining;
>  	size_t size_in;
> @@ -949,7 +947,7 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>  	rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
>  	if (rc < 0) {
>  		rc = FW_UPLOAD_ERR_RW_ERROR;
> -		goto out_free;
> +		return rc;

If you want to remove the goto here, just free transfer right after
calling cxl_internal_send_cmd(). It is no longer used then.

I only want those cleanup helpers where they are actually useful and
do not just add complexity.

Thanks,

-Robert

>  	}
>  
>  	*written = cur_size;
> @@ -963,14 +961,11 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>  			dev_err(&cxlmd->dev, "Error activating firmware: %d\n",
>  				rc);
>  			rc = FW_UPLOAD_ERR_HW_ERROR;
> -			goto out_free;
> +			return rc;
>  		}
>  	}
>  
>  	rc = FW_UPLOAD_ERR_NONE;
> -
> -out_free:
> -	kfree(transfer);
>  	return rc;
>  }
>  
> -- 
> 2.49.0
>