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123 Commits

Author SHA1 Message Date
Anton Nefedov
b0a335e351 qemu-char: socket backend: disconnect on write error 
Socket backend read handler should normally perform a disconnect, however
the read handler may not get a chance to run if the frontend is not ready
(qemu_chr_be_can_write() == 0).

This means that in virtio-serial frontend case if
 - the host has disconnected (giving EPIPE on socket write)
 - and the guest has disconnected (-> frontend not ready -> backend
   will not read)
 - and there is still data (frontend->backend) to flush (has to be a really
   tricky timing but nevertheless, we have observed the case in production)

This results in virtio-serial trying to flush this data continiously forming
a busy loop.

Solution: react on write error in the socket write handler.
errno is not reliable after qio_channel_writev_full(), so we may not get
the exact EPIPE, so disconnect on any error but QIO_CHANNEL_ERR_BLOCK which
io_channel_send_full() converts to errno EAGAIN.
We must not disconnect right away though, there still may be data to read
(see 4bf1cb0).

Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Daniel P. Berrange <berrange@redhat.com>
CC: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1486045589-8074-1-git-send-email-den@openvz.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
 2017-02-16 14:06:55 +01:00
Marc-André Lureau
213dcb060f char: headers clean-up 
Those could probably be squashed with earlier patches, however I
couldn't easily identify them, test them or check if there are still
necessary on various platforms.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:22 +04:00
Marc-André Lureau
6aa0f0c900 char: move parallel chardev in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
2b2f23dae7 char: move serial chardev to its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
c3b7d62097 char: move pty chardev in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
1fcb3841d0 char: move pipe chardev in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
7c7b2db0bd char: move console in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
d180081525 char: move stdio in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
6fdafac1c1 char: move file chardev in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
3b4482a26d char: move udp chardev in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
d24ca4b8c5 char: move socket chardev to its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
0e58f17777 char: move win-stdio into its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
503ebefe0a char: move win chardev base class in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
894593afbe char: move fd chardev in its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:21 +04:00
Marc-André Lureau
a6da7ffa38 char: move QIOChannel-related stuff to char-io.h 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
09fbe4e3e1 char: remove unused READ_RETRIES 
Curiously unused since its introduction in commit 7b0bfdf52d.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
f612143a03 char: rename and move to header CHR_READ_BUF_LEN 
This define is used by several character devices, place it in char
common header.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
bf51f62869 char: move ringbuf/memory to its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
df85a78bf8 char: move mux to its own file 
A mechanical move, except that qemu_chr_write_all() needs to be declared
in char.h header to be used from chardev unit files.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
247c92af2b char: move null chardev to its own file 
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
eb314a9497 char: make null_chr_write() the default method 
All chardev must implement chr_write(), but parallel and null chardev
both use null_chr_write(). Move it to the base class, so we don't need
to export the function when splitting the chardev in respective files.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
32d955a422 char: create chardev-obj-y 
This will help to split char.c in several units without having to
reference them all everywhere. This is useful in particular for tests.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 23:31:20 +04:00
Marc-André Lureau
178fe0ae9d char: move to chardev/ 
The following commits will split char.c in several files. Let's put them
in a subdirectory.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
 2017-01-31 13:03:46 +04:00