currently, nuttx implements readv/writev on the top of read/write.
while it might work for the simplest cases, it's broken by design.
for example, it's impossible to make it work correctly for files
which need to preserve data boundaries without allocating a single
contiguous buffer. (udp socket, some character devices, etc)
this change is a start of the migration to a better design.
that is, implement read/write on the top of readv/writev.
to avoid a single huge change, following things will NOT be done in
this commit:
* fix actual bugs caused by the original readv-based-on-read design.
(cf. https://github.com/apache/nuttx/pull/12674)
* adapt filesystems/drivers to actually benefit from the new interface.
(except a few trivial examples)
* eventually retire the old interface.
* retire read/write syscalls. implement them in libc instead.
* pread/pwrite/preadv/pwritev (except the introduction of struct uio,
which is a preparation to back these variations with the new
interface.)
since mmap may exist in block_operations, but truncate may not,
moving mmap beforee truncate could make three struct more compatible
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
- Add mmap into file_operations and remove it from ioctl definitions.
- Add mm_map structure definitions to support future unmapping
- Modify all drivers to initialize the operations struct accordingly
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
- Add truncate into file_operations
- Move truncate to be common for mountpt_operations and file_operations
- Modify all drivers to initialize the operations struct accordingly
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
