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

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Message-ID: <50a01a17-4afc-415d-b5c8-9a84e3bdf191@zohomail.com>
Date: Sun, 22 Jun 2025 20:22:45 +0800
From: Li Ming <ming.li@...omail.com>
To: Pranav Tyagi <pranav.tyagi03@...il.com>
Cc: rrichter@....com, peterz@...radead.org, skhan@...uxfoundation.org,
 linux-kernel-mentees@...ts.linux.dev, 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
Subject: Re: [PATCH] cxl/memdev: automate cleanup with __free()

On 6/22/2025 8:09 PM, 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 | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index f88a13adf7fa..be73a6099cb6 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 +803,11 @@ 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);
>  	if (!transfer)
>  		return -ENOMEM;
>  
> @@ -822,7 +823,6 @@ 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;
the rc can be removed with your change, can be "return cxl_internal_send_cmd(cxl_mbox, &mbox_cmd)".
>  }
>  
> @@ -880,7 +880,7 @@ 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);
>  	struct cxl_mbox_cmd mbox_cmd;
>  	u32 cur_size, remaining;
>  	size_t size_in;
> @@ -970,7 +970,6 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>  	rc = FW_UPLOAD_ERR_NONE;
>  
>  out_free:
> -	kfree(transfer);
>  	return rc;
>  }
>  

I believe all "goto out_free" in the function are not needed with your change.


Ming