This new function calculates a buffer size suitable for holding the
intended 9p request or response. For rather small message types (which
applies to almost all 9p message types actually) simply use hard coded
values. For some variable-length and potentially large message types
calculate a more precise value according to what data is actually
transmitted to avoid unnecessarily huge buffers.
So p9_msg_buf_size() divides the individual 9p message types into 3
message size categories:
- dynamically calculated message size (i.e. potentially large)
- 8k hard coded message size
- 4k hard coded message size
As for the latter two hard coded message types: for most 9p message
types it is pretty obvious whether they would always fit into 4k or
8k. But for some of them it depends on the maximum directory entry
name length allowed by OS and filesystem for determining into which
of the two size categories they would fit into. Currently Linux
supports directory entry names up to NAME_MAX (255), however when
comparing the limitation of individual filesystems, ReiserFS
theoretically supports up to slightly below 4k long names. So in
order to make this code more future proof, and as revisiting it
later on is a bit tedious and has the potential to miss out details,
the decision [1] was made to take 4k as basis as for max. name length.
Link: https://lkml.kernel.org/r/bd6be891cf67e867688e8c8796d06408bfafa0d9.1657920926.git.linux_oss@crudebyte.com
Link: https://lore.kernel.org/all/5564296.oo812IJUPE@silver/ [1]
Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Sohaib Mohamed started a serie of tiny and incomplete checkpatch fixes but
seemingly stopped halfway -- take over and do most of it.
This is still missing net/9p/trans* and net/9p/protocol.c for a later
time...
Link: http://lkml.kernel.org/r/20211102134608.1588018-3-dominique.martinet@atmark-techno.com
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to free software
foundation 51 franklin street fifth floor boston ma 02111 1301 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 27 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.981318839@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* remove lot of update to different data structure
* add a seperate callback for zero copy request.
* above makes non zero copy code path simpler
* remove conditionalizing TREAD/TREADDIR/TWRITE in the zero copy path
* Fix the dotu p9_check_errors with zero copy. Add sufficient doc around
* Add support for both in and output buffers in zero copy callback
* pin and unpin pages in the same context
* use helpers instead of defining page offset and rest of page ourself
* Fix mem leak in p9_check_errors
* Remove 'E' and 'F' in p9pdu_vwritef
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Removes 'dotu' variable and make everything dependent
on 'proto_version' field.
Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Now that the new protocol functions are in place, this patch switches
the client code to using the new support code.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
This adds a new protocol processing support code based on Anthony Liguori's
9p library code. This code performs protocol marshalling/unmarshalling using
printf like strings to represent protocol elements. It is my intent to use
them to replace the current functions in conv.c as well as the
p9_create_* functions.
This should make the client implementation much more clear, and also make it
much easier to add new protocol extensions by limiting the number of places
in which changes need to be made.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
