Re: [PATCH v2 2/8] cxl/mbox: Convert poison list mutex to ACQUIRE()

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Wed, 18 Jun 2025 22:04:10 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> Towards removing all explicit unlock calls in the CXL subsystem, convert
> the conditional poison list mutex to use a conditional lock guard.
> 
> Rename the lock to have the compiler validate that all existing call sites
> are converted.
> 
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Davidlohr Bueso <dave@stgolabs.net>
> Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

One trivial inline. Either way

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> ---
>  drivers/cxl/core/mbox.c | 7 +++----
>  drivers/cxl/cxlmem.h    | 4 ++--
>  2 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index 2689e6453c5a..81b21effe8cf 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -1401,8 +1401,8 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>  	int nr_records = 0;
>  	int rc;
>  
> -	rc = mutex_lock_interruptible(&mds->poison.lock);
> -	if (rc)
> +	ACQUIRE(mutex_intr, lock)(&mds->poison.mutex);

I'd slightly prefer the 'canonical' style from the cleanup.h docs in previous patch.

	rc = ACQUIRE_ERR(mutex_intr, &lock);
	if (rc)
		return rc;

> +	if ((rc = ACQUIRE_ERR(mutex_intr, &lock)))
>  		return rc;
>  
>  	po = mds->poison.list_out;
> @@ -1437,7 +1437,6 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>  		}
>  	} while (po->flags & CXL_POISON_FLAG_MORE);
>  
> -	mutex_unlock(&mds->poison.lock);
>  	return rc;
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_mem_get_poison, "CXL");
> @@ -1473,7 +1472,7 @@ int cxl_poison_state_init(struct cxl_memdev_state *mds)
>  		return rc;
>  	}
>  
> -	mutex_init(&mds->poison.lock);
> +	mutex_init(&mds->poison.mutex);
>  	return 0;
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_poison_state_init, "CXL");
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 551b0ba2caa1..f5b20641e57c 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -254,7 +254,7 @@ enum security_cmd_enabled_bits {
>   * @max_errors: Maximum media error records held in device cache
>   * @enabled_cmds: All poison commands enabled in the CEL
>   * @list_out: The poison list payload returned by device
> - * @lock: Protect reads of the poison list
> + * @mutex: Protect reads of the poison list
>   *
>   * Reads of the poison list are synchronized to ensure that a reader
>   * does not get an incomplete list because their request overlapped
> @@ -265,7 +265,7 @@ struct cxl_poison_state {
>  	u32 max_errors;
>  	DECLARE_BITMAP(enabled_cmds, CXL_POISON_ENABLED_MAX);
>  	struct cxl_mbox_poison_out *list_out;
> -	struct mutex lock;  /* Protect reads of poison list */
> +	struct mutex mutex;  /* Protect reads of poison list */
>  };
>  
>  /*