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The length information for available buffer space for CCA replies is covered with two fields in the T6 header prepended on each CCA reply: fromcardlen1 and fromcardlen2. The sum of these both values must not exceed the AP bus limit for this card (24KB for CEX8, 12KB CEX7 and older) minus the always present headers. The current code adjusted the fromcardlen2 value in case of exceeding the AP bus limit when there was a non-zero value given from userspace. Some tests now showed that this was the wrong assumption. Instead the userspace value given for this field should always be trusted and if the sum of the two fields exceeds the AP bus limit for this card the first field fromcardlen1 should be adjusted instead. So now the calculation is done with this new insight in mind. Also some additional checks for overflow have been introduced and some comments to provide some documentation for future maintainers of this complicated calculation code. Furthermore the 128 bytes of fix overhead which is used in the current code is not correct. Investigations showed that for a reply always the same two header structs are prepended before a possible payload. So this is also fixed with this patch. Signed-off-by: Harald Freudenberger <freude@linux.ibm.com> Reviewed-by: Holger Dengler <dengler@linux.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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.