[PATCH] state: backend: direct: open backend in read-only mode if possible

[Sascha Hauer]

On Mon, Jan 16, 2023 at 01:54:43PM +0100, Ahmad Fatoum wrote:
> We unconditionally open the device backing a direct bucket in read-write
> mode. We already populate struct state_backend_storage::readonly though,
> which we could consult at device open time. Do so. This could possibly
> be done for MTD as well, but until that's tested, for now, we do it only
> for the direct backend meant for use with block devices.
> 
> This has no functional change for barebox, which calls state_new_from_node
> in the DT driver and in the EFI initcall always with readonly=false, but
> we can benefit from this in barebox_state to open a device in read-only
> mode when possible (e.g. when called to --dump).
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
>  common/state/backend_bucket_direct.c | 4 ++--
>  common/state/backend_storage.c       | 2 +-
>  common/state/state.c                 | 6 +++---
>  common/state/state.h                 | 2 +-
>  4 files changed, 7 insertions(+), 7 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/common/state/backend_bucket_direct.c b/common/state/backend_bucket_direct.c
> index 3818c6f0b0ec..f06e14277862 100644
> --- a/common/state/backend_bucket_direct.c
> +++ b/common/state/backend_bucket_direct.c
> @@ -164,12 +164,12 @@ static void state_backend_bucket_direct_free(struct
>  
>  int state_backend_bucket_direct_create(struct device *dev, const char *path,
>  				       struct state_backend_storage_bucket **bucket,
> -				       off_t offset, ssize_t max_size)
> +				       off_t offset, ssize_t max_size, bool readonly)
>  {
>  	int fd;
>  	struct state_backend_storage_bucket_direct *direct;
>  
> -	fd = open(path, O_RDWR);
> +	fd = open(path, readonly ? O_RDONLY : O_RDWR);
>  	if (fd < 0) {
>  		dev_err(dev, "Failed to open file '%s', %d\n", path, -errno);
>  		return -errno;
> diff --git a/common/state/backend_storage.c b/common/state/backend_storage.c
> index c55d22e37f70..df81902bf7be 100644
> --- a/common/state/backend_storage.c
> +++ b/common/state/backend_storage.c
> @@ -332,7 +332,7 @@ static int state_storage_file_buckets_init(struct state_backend_storage *storage
>  		offset = storage->offset + n * stridesize;
>  		ret = state_backend_bucket_direct_create(storage->dev, storage->path,
>  							 &bucket, offset,
> -							 stridesize);
> +							 stridesize, storage->readonly);
>  		if (ret) {
>  			dev_warn(storage->dev, "Failed to create direct bucket at '%s' offset %lld\n",
>  				 storage->path, (long long) offset);
> diff --git a/common/state/state.c b/common/state/state.c
> index a614c849c74e..cabe285fbdf3 100644
> --- a/common/state/state.c
> +++ b/common/state/state.c
> @@ -653,14 +653,14 @@ struct state *state_new_from_node(struct device_node *node, bool readonly)
>  	if (ret)
>  		goto out_release_state;
>  
> +	if (readonly)
> +		state_backend_set_readonly(state);
> +
>  	ret = state_storage_init(state, state->backend_path, offset,
>  				 size, stridesize, storage_type);
>  	if (ret)
>  		goto out_release_state;
>  
> -	if (readonly)
> -		state_backend_set_readonly(state);
> -
>  	ret = state_from_node(state, node, 1);
>  	if (ret) {
>  		goto out_release_state;
> diff --git a/common/state/state.h b/common/state/state.h
> index 7eb51bbdb57d..f0c5b1de4123 100644
> --- a/common/state/state.h
> +++ b/common/state/state.h
> @@ -226,7 +226,7 @@ void state_backend_set_readonly(struct state *state);
>  void state_storage_free(struct state_backend_storage *storage);
>  int state_backend_bucket_direct_create(struct device *dev, const char *path,
>  				       struct state_backend_storage_bucket **bucket,
> -				       off_t offset, ssize_t max_size);
> +				       off_t offset, ssize_t max_size, bool readonly);
>  int state_storage_write(struct state_backend_storage *storage,
>  			const void * buf, ssize_t len);
>  int state_storage_read(struct state_backend_storage *storage,
> -- 
> 2.30.2
> 
> 
> 

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