ANDROID: Squashfs: replace buffer_head with BIO
The 'll_rw_block' has been deprecated and BIO is now the basic container
for block I/O within the kernel.
Switching to BIO offers 2 advantages:
1/ It removes synchronous wait for the up-to-date buffers: SquashFS
now deals with decompressions/copies asynchronously.
Implementing an asynchronous mechanism to read data is needed to
efficiently implement .readpages().
2/ Prior to this patch, merging the read requests entirely depends on
the IO scheduler. SquashFS has more information than the IO
scheduler about what could be merged. Moreover, merging the reads
at the FS level means that we rely less on the IO scheduler.
Change-Id: I668812cc1e78e2f92497f9ebe0157cb8eec725ba
Signed-off-by: Adrien Schildknecht <adriens@google.com>
4 files changed