On Tue, Jul 30, 2024 at 09:16:32AM +0200, Ahmad Fatoum wrote:
> In barebox, the dirty block cache for a given device is flushed when
> closing all file descriptors to it, a cached block needs to be evicted
> due to pressure or when barebox shuts down.
>
> There are valid uses to do it explicitly however:
>
> - When benchmarking write speed to a block device
> - Before forced resets, because a regular reset would run shutdown
> code that should be omitted.
>
> Add a sync command that does this. Unlike the userspace variant, we
> don't both to implement a argument-less sync that's global. Users are
> supposed to flush the files they are actually interested in, e.g.:
>
> sync /dev/mmc2.0
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
I'll drop this one in favor for the same patch included in your mmc
erase support series.
Sascha
> ---
> commands/Kconfig | 14 ++++++++++++++
> commands/Makefile | 1 +
> commands/sync.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 57 insertions(+)
> create mode 100644 commands/sync.c
>
> diff --git a/commands/Kconfig b/commands/Kconfig
> index 5b512f1bbac7..a8b7037618cc 100644
> --- a/commands/Kconfig
> +++ b/commands/Kconfig
> @@ -1871,6 +1871,20 @@ config CMD_DETECT
> -e bail out if one device fails to detect
> -a detect all devices
>
> +config CMD_SYNC
> + tristate
> + prompt "sync"
> + help
> + sync - flush cached writes
> +
> + Usage: sync DEVICE
> +
> + Synchronize cached writes to persistent storage of DEVICE
> + immediately instead of waiting for block device to be closed,
> + cache eviction or the regular barebox exit.
> +
> + This command is mainly useful for benchmarking.
> +
> config CMD_FLASH
> tristate
> prompt "erase, protect and unprotect"
> diff --git a/commands/Makefile b/commands/Makefile
> index 4ca7ba7eb609..a9dbead4389f 100644
> --- a/commands/Makefile
> +++ b/commands/Makefile
> @@ -41,6 +41,7 @@ obj-$(CONFIG_CMD_REGINFO) += reginfo.o
> obj-$(CONFIG_CMD_CRC) += crc.o
> obj-$(CONFIG_CMD_CLEAR) += clear.o
> obj-$(CONFIG_CMD_TEST) += test.o
> +obj-$(CONFIG_CMD_SYNC) += sync.o
> obj-$(CONFIG_CMD_FLASH) += flash.o
> obj-$(CONFIG_CMD_MEMINFO) += meminfo.o
> obj-$(CONFIG_CMD_TIMEOUT) += timeout.o
> diff --git a/commands/sync.c b/commands/sync.c
> new file mode 100644
> index 000000000000..6add67cd0876
> --- /dev/null
> +++ b/commands/sync.c
> @@ -0,0 +1,42 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +/* sync - flushing support */
> +
> +#include <common.h>
> +#include <command.h>
> +#include <fcntl.h>
> +#include <fs.h>
> +
> +static int do_sync(int argc, char *argv[])
> +{
> + int ret, fd;
> +
> + if (argc != 2)
> + return COMMAND_ERROR_USAGE;
> +
> + fd = open(argv[1], O_WRONLY);
> + if (fd < 0) {
> + printf("open %s: %m\n", argv[1]);
> + return 1;
> + }
> +
> + ret = flush(fd);
> +
> + close(fd);
> +
> + return ret;
> +}
> +
> +BAREBOX_CMD_HELP_START(sync)
> +BAREBOX_CMD_HELP_TEXT("Synchronize cached writes to persistent storage of DEVICE")
> +BAREBOX_CMD_HELP_TEXT("immediately instead of waiting for block device to be closed,")
> +BAREBOX_CMD_HELP_TEXT("cache eviction or the regular barebox exit.")
> +BAREBOX_CMD_HELP_END
> +
> +BAREBOX_CMD_START(sync)
> + .cmd = do_sync,
> + BAREBOX_CMD_DESC("flush cached writes")
> + BAREBOX_CMD_OPTS("DEVICE")
> + BAREBOX_CMD_GROUP(CMD_GRP_HWMANIP)
> + BAREBOX_CMD_HELP(cmd_sync_help)
> +BAREBOX_CMD_END
> --
> 2.39.2
>
>
>
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