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714e76347a
If VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS is activated, the user mode
linux virtio irq handler only read one msg from the corresponding socket.
This creates issues, when the device emulation creates multiple call
requests (e.g. for multiple virtqueues), as the socket buffer tend to fill
up and the call requests are delayed.
This creates a deadlock situation, when the device simulation blocks,
because of sending a msg and the kernel side blocks because of
synchronously waiting for an acknowledge of kick request.
Actually inband notifications are meant to be used in combination with the
time travel protocol, but it is not required, therefore this corner case
needs to be handled.
Anyways, in general it seems to be more natural to consume always all
messages from a socket, instead of only a single one.
Fixes: 2cd097ba8c ("um: virtio: Implement VHOST_USER_PROTOCOL_F_SLAVE_REQ")
Signed-off-by: Benjamin Beichler <benjamin.beichler@uni-rostock.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Richard Weinberger <richard@nod.at>
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.