kernel.git/drivers/char/virtio_console.c, branch linux-4.8.y

virtio: console: Unlock vqs while freeing buffers

2016-11-10T15:38:52Z

commit 34563769e438d2881f62cf4d9badc4e589ac0ec0 upstream. Commit c6017e793b93 ("virtio: console: add locks around buffer removal in port unplug path") added locking around the freeing of buffers in the vq. However, when free_buf() is called with can_sleep = true and rproc is enabled, it calls dma_free_coherent() directly, requiring interrupts to be enabled. Currently a WARNING is triggered due to the spin locking around free_buf, with a call stack like this: WARNING: CPU: 3 PID: 121 at ./include/linux/dma-mapping.h:433 free_buf+0x1a8/0x288 Call Trace: [<8040c538>] show_stack+0x74/0xc0 [<80757240>] dump_stack+0xd0/0x110 [<80430d98>] __warn+0xfc/0x130 [<80430ee0>] warn_slowpath_null+0x2c/0x3c [<807e7c6c>] free_buf+0x1a8/0x288 [<807ea590>] remove_port_data+0x50/0xac [<807ea6a0>] unplug_port+0xb4/0x1bc [<807ea858>] virtcons_remove+0xb0/0xfc [<807b6734>] virtio_dev_remove+0x58/0xc0 [<807f918c>] __device_release_driver+0xac/0x134 [<807f924c>] device_release_driver+0x38/0x50 [<807f7edc>] bus_remove_device+0xfc/0x130 [<807f4b74>] device_del+0x17c/0x21c [<807f4c38>] device_unregister+0x24/0x38 [<807b6b50>] unregister_virtio_device+0x28/0x44 Fix this by restructuring the loops to allow the locks to only be taken where it is necessary to protect the vqs, and release it while the buffer is being freed. Fixes: c6017e793b93 ("virtio: console: add locks around buffer removal in port unplug path") Signed-off-by: Matt Redfearn Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_console: Stop doing DMA on the stack

2016-09-09T18:12:45Z

virtio_console uses a small DMA buffer for control requests. Move that buffer into heap memory. Doing virtio DMA on the stack is normally okay on non-DMA-API virtio systems (which is currently most of them), but it breaks completely if the stack is virtually mapped. Tested by typing both directions using picocom aimed at /dev/hvc0. Signed-off-by: Andy Lutomirski Signed-off-by: Michael S. Tsirkin Reviewed-by: Amit Shah

virtio_console: silence a static checker warning

2015-05-24T19:24:35Z

My static checker complains that this sprintf() can overflow but really it can't. Just silence the warning by using snprintf(). Signed-off-by: Dan Carpenter Reviewed-by: Amit Shah Signed-off-by: Greg Kroah-Hartman

virtio_console: Use bool function return values of true/false not 1/0

2015-04-03T14:15:30Z

Use the normal return values for bool functions Signed-off-by: Joe Perches Reviewed-by: Amit Shah Signed-off-by: Greg Kroah-Hartman

virtio_console: avoid config access from irq

2015-03-05T03:06:18Z

when multiport is off, virtio console invokes config access from irq context, config access is blocking on s390. Fix this up by scheduling work from config irq - similar to what we do for multiport configs. Signed-off-by: Michael S. Tsirkin Reviewed-by: Amit Shah Signed-off-by: Rusty Russell Cc: stable@kernel.org

virtio_console: init work unconditionally

2015-03-05T03:06:17Z

when multiport is off, we don't initialize config work, but we then cancel uninitialized control_work on freeze. Signed-off-by: Michael S. Tsirkin Reviewed-by: Amit Shah Signed-off-by: Rusty Russell Cc: stable@kernel.org

virtio: don't require a config space on the console device.

2015-02-11T04:33:17Z

Strictly, it's only needed when we have features (size or multiport). Signed-off-by: Rusty Russell

virtio/console: verify device has config space

2015-01-21T05:58:46Z

Some devices might not implement config space access (e.g. remoteproc used not to - before 3.9). virtio/console needs config space access so make it fail gracefully if not there. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell

virtio_console: fix sparse warnings

2014-12-09T10:06:33Z

CHECK drivers/char/virtio_console.c drivers/char/virtio_console.c:687:36: warning: incorrect type in argument 1 (different address spaces) drivers/char/virtio_console.c:687:36: expected void [noderef] *to drivers/char/virtio_console.c:687:36: got char *out_buf drivers/char/virtio_console.c:790:35: warning: incorrect type in argument 2 (different address spaces) drivers/char/virtio_console.c:790:35: expected char *out_buf drivers/char/virtio_console.c:790:35: got char [noderef] *ubuf fill_readbuf is reused with both kernel and userspace pointers, depending on value of to_user flag. Tag address parameter as __user, and cast to/from regular pointer type when we know it's safe. Signed-off-by: Michael S. Tsirkin

virtio: drop VIRTIO_F_VERSION_1 from drivers

2014-12-09T10:06:32Z

Core activates this bit automatically now, drop it from drivers that set it explicitly. Signed-off-by: Michael S. Tsirkin