Re: [PATCH v2 3/3] powerpc/ps3: use put_device() on device_register() failure in ps3_system_bus_device_register

On 13/08/26 15:24, Tarun Sahu wrote:
> When device_register() fails, calling put_device() ensures that the
> device reference count drops to 0, which invokes the release callback
> ps3_system_bus_release_device() to cleanly free the device and its
> associated driver core resources.

Yes, since the PS3 device has a release function, put_device() should be
used instead of manually freeing the memory, as described in 
device_register().

Changes look good to me. Feel free to add:
Reviewed-by: Sourabh Jain <[email protected]>

>
> Signed-off-by: Tarun Sahu <[email protected]>
> ---
>   arch/powerpc/platforms/ps3/device-init.c | 83 ++++++++++++++----------
>   arch/powerpc/platforms/ps3/system-bus.c  |  2 +
>   2 files changed, 52 insertions(+), 33 deletions(-)
>
> diff --git a/arch/powerpc/platforms/ps3/device-init.c b/arch/powerpc/platforms/ps3/device-init.c
> index 9109c218a060..8d0c77db1764 100644
> --- a/arch/powerpc/platforms/ps3/device-init.c
> +++ b/arch/powerpc/platforms/ps3/device-init.c
> @@ -90,14 +90,12 @@ static int __init ps3_register_lpm_devices(void)
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_register;
> +		return result;
>   	}
>   
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return 0;
>   
> -
> -fail_register:
>   fail_rights:
>   fail_read_repo:
>   	kfree(dev);
> @@ -121,6 +119,12 @@ static int __init ps3_setup_gelic_device(
>   		struct ps3_dma_region d_region;
>   	} *p;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->dev).
> +	 * dev must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct layout, dev) != 0);
> +
>   	pr_debug(" -> %s:%d\n", __func__, __LINE__);
>   
>   	BUG_ON(repo->bus_type != PS3_BUS_TYPE_SB);
> @@ -164,13 +168,12 @@ static int __init ps3_setup_gelic_device(
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return result;
>   
> -fail_device_register:
>   fail_dma_init:
>   fail_find_interrupt:
>   	kfree(p);
> @@ -192,6 +195,12 @@ static int __init ps3_setup_uhc_device(
>   	u64 bus_addr;
>   	u64 len;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->dev).
> +	 * dev must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct layout, dev) != 0);
> +
>   	pr_debug(" -> %s:%d\n", __func__, __LINE__);
>   
>   	BUG_ON(repo->bus_type != PS3_BUS_TYPE_SB);
> @@ -252,13 +261,12 @@ static int __init ps3_setup_uhc_device(
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return result;
>   
> -fail_device_register:
>   fail_mmio_init:
>   fail_dma_init:
>   fail_find_reg:
> @@ -291,6 +299,12 @@ static int __init ps3_setup_vuart_device(enum ps3_match_id match_id,
>   		struct ps3_system_bus_device dev;
>   	} *p;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->dev).
> +	 * dev must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct layout, dev) != 0);
> +
>   	pr_debug(" -> %s:%d: match_id %u, port %u\n", __func__, __LINE__,
>   		match_id, port_number);
>   
> @@ -308,15 +322,10 @@ static int __init ps3_setup_vuart_device(enum ps3_match_id match_id,
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return 0;
> -
> -fail_device_register:
> -	kfree(p);
> -	pr_debug(" <- %s:%d fail\n", __func__, __LINE__);
> -	return result;
>   }
>   
>   static int ps3_setup_storage_dev(const struct ps3_repository_device *repo,
> @@ -327,6 +336,12 @@ static int ps3_setup_storage_dev(const struct ps3_repository_device *repo,
>   	u64 port, blk_size, num_blocks;
>   	unsigned int num_regions, i;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->sbd).
> +	 * sbd must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct ps3_storage_device, sbd) != 0);
> +
>   	pr_debug(" -> %s:%u: match_id %u\n", __func__, __LINE__, match_id);
>   
>   	result = ps3_repository_read_stor_dev_info(repo->bus_index,
> @@ -395,13 +410,12 @@ static int ps3_setup_storage_dev(const struct ps3_repository_device *repo,
>   	if (result) {
>   		pr_debug("%s:%u ps3_system_bus_device_register failed\n",
>   			 __func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   
>   	pr_debug(" <- %s:%u\n", __func__, __LINE__);
>   	return 0;
>   
> -fail_device_register:
>   fail_read_region:
>   fail_find_interrupt:
>   	kfree(p);
> @@ -445,6 +459,12 @@ static int __init ps3_register_sound_devices(void)
>   		struct ps3_mmio_region m_region;
>   	} *p;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->dev).
> +	 * dev must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct layout, dev) != 0);
> +
>   	pr_debug(" -> %s:%d\n", __func__, __LINE__);
>   
>   	p = kzalloc_obj(*p);
> @@ -461,15 +481,10 @@ static int __init ps3_register_sound_devices(void)
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return 0;
> -
> -fail_device_register:
> -	kfree(p);
> -	pr_debug(" <- %s:%d failed\n", __func__, __LINE__);
> -	return result;
>   }
>   
>   static int __init ps3_register_graphics_devices(void)
> @@ -479,6 +494,12 @@ static int __init ps3_register_graphics_devices(void)
>   		struct ps3_system_bus_device dev;
>   	} *p;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->dev).
> +	 * dev must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct layout, dev) != 0);
> +
>   	pr_debug(" -> %s:%d\n", __func__, __LINE__);
>   
>   	p = kzalloc_obj(struct layout);
> @@ -495,16 +516,11 @@ static int __init ps3_register_graphics_devices(void)
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return 0;
> -
> -fail_device_register:
> -	kfree(p);
> -	pr_debug(" <- %s:%d failed\n", __func__, __LINE__);
> -	return result;
>   }
>   
>   static int __init ps3_register_ramdisk_device(void)
> @@ -514,6 +530,12 @@ static int __init ps3_register_ramdisk_device(void)
>   		struct ps3_system_bus_device dev;
>   	} *p;
>   
> +	/*
> +	 * ps3_system_bus_release_device() calls kfree(&p->dev).
> +	 * dev must be at offset 0 so kfree() frees outer p.
> +	 */
> +	BUILD_BUG_ON(offsetof(struct layout, dev) != 0);
> +
>   	pr_debug(" -> %s:%d\n", __func__, __LINE__);
>   
>   	p = kzalloc_obj(struct layout);
> @@ -530,16 +552,11 @@ static int __init ps3_register_ramdisk_device(void)
>   	if (result) {
>   		pr_debug("%s:%d ps3_system_bus_device_register failed\n",
>   			__func__, __LINE__);
> -		goto fail_device_register;
> +		return result;
>   	}
>   
>   	pr_debug(" <- %s:%d\n", __func__, __LINE__);
>   	return 0;
> -
> -fail_device_register:
> -	kfree(p);
> -	pr_debug(" <- %s:%d failed\n", __func__, __LINE__);
> -	return result;
>   }
>   
>   /**
> diff --git a/arch/powerpc/platforms/ps3/system-bus.c b/arch/powerpc/platforms/ps3/system-bus.c
> index 0537a678a32f..0918c74d3e19 100644
> --- a/arch/powerpc/platforms/ps3/system-bus.c
> +++ b/arch/powerpc/platforms/ps3/system-bus.c
> @@ -774,6 +774,8 @@ int ps3_system_bus_device_register(struct ps3_system_bus_device *dev)
>   	pr_debug("%s:%d add %s\n", __func__, __LINE__, dev_name(&dev->core));
>   
>   	result = device_register(&dev->core);
> +	if (result)
> +		put_device(&dev->core);
>   	return result;
>   }
>