FROMGIT: binder: malloc new_buffer outside of locks

Preallocate new_buffer before acquiring the alloc->mutex and hand it
down to binder_alloc_new_buf_locked(). The new buffer will be used in
the vast majority of requests (measured at 98.2% in field data). The
buffer is discarded otherwise. This change is required in preparation
for transitioning alloc->mutex into a spinlock in subsequent commits.

Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20231201172212.1813387-18-cmllamas@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 254650075
Bug: 320576997
(cherry picked from commit c7ac30fa
 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git


 char-misc-next)
Change-Id: Ib7c8eb3c53e8383694a118fabc776a6a22783c75
Signed-off-by: Carlos Llamas <cmllamas@google.com>