[OSS-Tools] [PATCH 0/3] state: void partition table reread when possible

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

So far, barebox-state with a MMC backend always opened the whole disk
read/write, which triggers a partition table reread when closing the
device. This can be avoided in some cases:

  - If we are only interested in reading, we can open it O_RDONLY

  - If there happens to be an on-disk-described partition at exactly
    the region we are interested, we can open that instead.

So let's do that. The result can be easily verified with strace.
Without this patch:

  openat(AT_FDCWD, "/dev/mmcblk0", O_RDWR|O_LARGEFILE) = 4

With this patch:

  openat(AT_FDCWD, "/dev/mmcblk0p6", O_RDONLY|O_LARGEFILE) = 4

Ahmad Fatoum (3):
  state: backend: direct: open block device in read-only mode if
    possible
  libdt: factor out u64 sysattr parsing into helper
  libdt: use block device partition instead of parent if found

 src/barebox-state/backend_bucket_direct.c |   5 +-
 src/barebox-state/backend_storage.c       |   2 +-
 src/barebox-state/state.c                 |   6 +-
 src/barebox-state/state.h                 |   3 +-
 src/libdt.c                               | 104 +++++++++++++++++-----
 5 files changed, 92 insertions(+), 28 deletions(-)

-- 
2.39.2