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

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Message-ID: <CAH4c4jLYSXsWE8aDV0Cue0y0xMoYKbfN_Tkoj8SuAreDidG1dw@mail.gmail.com>
Date: Sun, 22 Jun 2025 18:20:39 +0530
From: Pranav Tyagi <pranav.tyagi03@...il.com>
To: Li Ming <ming.li@...omail.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 Sun, Jun 22, 2025 at 5:53 PM Li Ming <ming.li@...omail.com> wrote:
>
> 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
>

Hi,

Thanks for the feedback.

You're absolutely right - with __free() handling cleanup, the
explicit rc variable and the goto out_free blocks can now be
eliminated.

I'll send a v2 shortly incorporating these cleanups.

Regards
Pranav Tyagi