12382d1167
Transactions are always allocated one at a time. The maximum number of them we could ever need occurs if each TRE is assigned to a transaction. So a channel requires no more transactions than the number of TREs in its transfer ring. That number is known to be a power-of-2 less than 65536. The transaction pool abstraction is used for other things, but for transactions we can use a simple array of transaction structures, and use a free index to indicate which entry in the array is the next one free for allocation. By having the number of elements in the array be a power-of-2, we can use an ever-incrementing 16-bit free index, and use it modulo the array size. Distinguish a "trans_id" (whose value can exceed the number of entries in the transaction array) from a "trans_index" (which is less than the number of entries). Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.