Re: [PATCH v2 1/2] tpm: Use managed allocation for bios event log

[Jarkko Sakkinen <jarkko@kernel.org>]

On Fri, Jan 13, 2023 at 10:10:16AM -0600, Eddie James wrote:
> Since the bios event log is freed in the device release function,
> let devres handle the deallocation. This will allow other memory
> allocation/mapping functions to be used for the bios event log.
> 
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> ---
>  drivers/char/tpm/eventlog/acpi.c |  5 +++--
>  drivers/char/tpm/eventlog/efi.c  | 13 +++++++------
>  drivers/char/tpm/eventlog/of.c   |  3 ++-
>  drivers/char/tpm/tpm-chip.c      |  1 -
>  4 files changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/char/tpm/eventlog/acpi.c b/drivers/char/tpm/eventlog/acpi.c
> index 0913d3eb8d51..40360e599bc3 100644
> --- a/drivers/char/tpm/eventlog/acpi.c
> +++ b/drivers/char/tpm/eventlog/acpi.c
> @@ -14,6 +14,7 @@
>   * Access to the event log extended by the TCG BIOS of PC platform
>   */
>  
> +#include <linux/device.h>
>  #include <linux/seq_file.h>
>  #include <linux/fs.h>
>  #include <linux/security.h>
> @@ -135,7 +136,7 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
>  	}
>  
>  	/* malloc EventLog space */
> -	log->bios_event_log = kmalloc(len, GFP_KERNEL);
> +	log->bios_event_log = devm_kmalloc(&chip->dev, len, GFP_KERNEL);
>  	if (!log->bios_event_log)
>  		return -ENOMEM;
>  
> @@ -160,7 +161,7 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
>  	return format;
>  
>  err:
> -	kfree(log->bios_event_log);
> +	devm_kfree(&chip->dev, log->bios_event_log);

I wonder do we want to do devm_kfree's at all as the memory is freed during
detach, i.e. taken care by devres.

>  	log->bios_event_log = NULL;
>  	return ret;
>  }
> diff --git a/drivers/char/tpm/eventlog/efi.c b/drivers/char/tpm/eventlog/efi.c
> index e6cb9d525e30..4e9d7c2bf32e 100644
> --- a/drivers/char/tpm/eventlog/efi.c
> +++ b/drivers/char/tpm/eventlog/efi.c
> @@ -6,6 +6,7 @@
>   *      Thiebaud Weksteen <tweek@google.com>
>   */
>  
> +#include <linux/device.h>
>  #include <linux/efi.h>
>  #include <linux/tpm_eventlog.h>
>  
> @@ -55,7 +56,7 @@ int tpm_read_log_efi(struct tpm_chip *chip)
>  	}
>  
>  	/* malloc EventLog space */
> -	log->bios_event_log = kmemdup(log_tbl->log, log_size, GFP_KERNEL);
> +	log->bios_event_log = devm_kmemdup(&chip->dev, log_tbl->log, log_size, GFP_KERNEL);
>  	if (!log->bios_event_log) {
>  		ret = -ENOMEM;
>  		goto out;
> @@ -76,7 +77,7 @@ int tpm_read_log_efi(struct tpm_chip *chip)
>  			     MEMREMAP_WB);
>  	if (!final_tbl) {
>  		pr_err("Could not map UEFI TPM final log\n");
> -		kfree(log->bios_event_log);
> +		devm_kfree(&chip->dev, log->bios_event_log);
>  		ret = -ENOMEM;
>  		goto out;
>  	}
> @@ -91,11 +92,11 @@ int tpm_read_log_efi(struct tpm_chip *chip)
>  	 * Allocate memory for the 'combined log' where we will append the
>  	 * 'final events log' to.
>  	 */
> -	tmp = krealloc(log->bios_event_log,
> -		       log_size + final_events_log_size,
> -		       GFP_KERNEL);
> +	tmp = devm_krealloc(&chip->dev, log->bios_event_log,
> +			    log_size + final_events_log_size,
> +			    GFP_KERNEL);
>  	if (!tmp) {
> -		kfree(log->bios_event_log);
> +		devm_kfree(&chip->dev, log->bios_event_log);
>  		ret = -ENOMEM;
>  		goto out;
>  	}
> diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
> index a9ce66d09a75..741ab2204b11 100644
> --- a/drivers/char/tpm/eventlog/of.c
> +++ b/drivers/char/tpm/eventlog/of.c
> @@ -10,6 +10,7 @@
>   * Read the event log created by the firmware on PPC64
>   */
>  
> +#include <linux/device.h>
>  #include <linux/slab.h>
>  #include <linux/of.h>
>  #include <linux/tpm_eventlog.h>
> @@ -65,7 +66,7 @@ int tpm_read_log_of(struct tpm_chip *chip)
>  		return -EIO;
>  	}
>  
> -	log->bios_event_log = kmemdup(__va(base), size, GFP_KERNEL);
> +	log->bios_event_log = devm_kmemdup(&chip->dev, __va(base), size, GFP_KERNEL);
>  	if (!log->bios_event_log)
>  		return -ENOMEM;
>  
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 741d8f3e8fb3..b99f55f2d4fd 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -267,7 +267,6 @@ static void tpm_dev_release(struct device *dev)
>  	idr_remove(&dev_nums_idr, chip->dev_num);
>  	mutex_unlock(&idr_lock);
>  
> -	kfree(chip->log.bios_event_log);
>  	kfree(chip->work_space.context_buf);
>  	kfree(chip->work_space.session_buf);
>  	kfree(chip->allocated_banks);
> -- 
> 2.31.1
> 

BR, Jarkko