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
