Re: Patch to the context lookup change

[Stephen Smalley <sds@tycho.nsa.gov>]

On 3/11/19 3:36 PM, Tianjie Xu wrote:
> Hi there,
> I recently made a change in android's selinux repo. The change
> implements a new lookup helper function for context matches, and it
> aims to skip unnecessary restorecon if the corresponding context
> doesn't change.
> 
> Quote from the commit message. "We used to hash the file_context and
> skip the restorecon on the top level directory if the hash doesn't
> change. But the file_context might change after an OTA update; and
> some users experienced long restorecon time as they have lots of files
> under directories like /data/media. This CL tries to hash all the
> partial match entries in the file_context for each directory; and
> skips the restorecon if that digest stays the same, regardless of the
> changes to the other parts of file_context."
> CL in: https://android-review.googlesource.com/c/platform/external/selinux/+/918713
> 
> I haven't done the work in upstream code to fully implement this
> change. But this CL merges and compiles. It factors out a lookup
> helper function and returns an array of matched pointers instead of a
> single one. The old loopup_common function is then modified to take
> the first element in the array. I wonder if it's possible to merge in
> this change to the lookup functions first? It will make the upstream &
> android repo more consistent and also save some work for future
> merges.

Just like Linux kernel submitting patches [1][2], we want patches to be 
inline in the message for easier review and inline commenting.  Best way 
to do it is to use git send-email after first using git commit --amend 
to work some of the rationale above into the commit message.  See also:

[1] 
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#submittingpatches

[2] https://www.ozlabs.org/~akpm/stuff/tpp.txt