linux/include/media/videobuf2-core.h

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/*
* videobuf2-core.h - Video Buffer 2 Core Framework
*
* Copyright (C) 2010 Samsung Electronics
*
* Author: Pawel Osciak <pawel@osciak.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation.
*/
#ifndef _MEDIA_VIDEOBUF2_CORE_H
#define _MEDIA_VIDEOBUF2_CORE_H
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/dma-buf.h>
#define VB2_MAX_FRAME (32)
#define VB2_MAX_PLANES (8)
enum vb2_memory {
VB2_MEMORY_UNKNOWN = 0,
VB2_MEMORY_MMAP = 1,
VB2_MEMORY_USERPTR = 2,
VB2_MEMORY_DMABUF = 4,
};
struct vb2_alloc_ctx;
struct vb2_fileio_data;
struct vb2_threadio_data;
/**
* struct vb2_mem_ops - memory handling/memory allocator operations
* @alloc: allocate video memory and, optionally, allocator private data,
* return NULL on failure or a pointer to allocator private,
* per-buffer data on success; the returned private structure
* will then be passed as buf_priv argument to other ops in this
* structure. Additional gfp_flags to use when allocating the
* are also passed to this operation. These flags are from the
* gfp_flags field of vb2_queue.
* @put: inform the allocator that the buffer will no longer be used;
* usually will result in the allocator freeing the buffer (if
* no other users of this buffer are present); the buf_priv
* argument is the allocator private per-buffer structure
* previously returned from the alloc callback.
* @get_dmabuf: acquire userspace memory for a hardware operation; used for
* DMABUF memory types.
* @get_userptr: acquire userspace memory for a hardware operation; used for
* USERPTR memory types; vaddr is the address passed to the
* videobuf layer when queuing a video buffer of USERPTR type;
* should return an allocator private per-buffer structure
* associated with the buffer on success, NULL on failure;
* the returned private structure will then be passed as buf_priv
* argument to other ops in this structure.
* @put_userptr: inform the allocator that a USERPTR buffer will no longer
* be used.
* @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
* used for DMABUF memory types; alloc_ctx is the alloc context
* dbuf is the shared dma_buf; returns NULL on failure;
* allocator private per-buffer structure on success;
* this needs to be used for further accesses to the buffer.
* @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
* buffer is no longer used; the buf_priv argument is the
* allocator private per-buffer structure previously returned
* from the attach_dmabuf callback.
* @map_dmabuf: request for access to the dmabuf from allocator; the allocator
* of dmabuf is informed that this driver is going to use the
* dmabuf.
* @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
* that this driver is done using the dmabuf for now.
* @prepare: called every time the buffer is passed from userspace to the
* driver, useful for cache synchronisation, optional.
* @finish: called every time the buffer is passed back from the driver
* to the userspace, also optional.
* @vaddr: return a kernel virtual address to a given memory buffer
* associated with the passed private structure or NULL if no
* such mapping exists.
* @cookie: return allocator specific cookie for a given memory buffer
* associated with the passed private structure or NULL if not
* available.
* @num_users: return the current number of users of a memory buffer;
* return 1 if the videobuf layer (or actually the driver using
* it) is the only user.
* @mmap: setup a userspace mapping for a given memory buffer under
* the provided virtual memory region.
*
* Required ops for USERPTR types: get_userptr, put_userptr.
* Required ops for MMAP types: alloc, put, num_users, mmap.
* Required ops for read/write access types: alloc, put, num_users, vaddr.
* Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
* unmap_dmabuf.
*/
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size,
enum dma_data_direction dma_dir,
gfp_t gfp_flags);
void (*put)(void *buf_priv);
struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
unsigned long size,
enum dma_data_direction dma_dir);
void (*put_userptr)(void *buf_priv);
void (*prepare)(void *buf_priv);
void (*finish)(void *buf_priv);
void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size,
enum dma_data_direction dma_dir);
void (*detach_dmabuf)(void *buf_priv);
int (*map_dmabuf)(void *buf_priv);
void (*unmap_dmabuf)(void *buf_priv);
void *(*vaddr)(void *buf_priv);
void *(*cookie)(void *buf_priv);
unsigned int (*num_users)(void *buf_priv);
int (*mmap)(void *buf_priv, struct vm_area_struct *vma);
};
/**
* struct vb2_plane - plane information
* @mem_priv: private data with this plane
* @dbuf: dma_buf - shared buffer object
* @dbuf_mapped: flag to show whether dbuf is mapped or not
* @bytesused: number of bytes occupied by data in the plane (payload)
* @length: size of this plane (NOT the payload) in bytes
* @min_length: minimum required size of this plane (NOT the payload) in bytes.
* @length is always greater or equal to @min_length.
* @offset: when memory in the associated struct vb2_buffer is
* VB2_MEMORY_MMAP, equals the offset from the start of
* the device memory for this plane (or is a "cookie" that
* should be passed to mmap() called on the video node)
* @userptr: when memory is VB2_MEMORY_USERPTR, a userspace pointer
* pointing to this plane
* @fd: when memory is VB2_MEMORY_DMABUF, a userspace file
* descriptor associated with this plane
* @m: Union with memtype-specific data (@offset, @userptr or
* @fd).
* @data_offset: offset in the plane to the start of data; usually 0,
* unless there is a header in front of the data
* Should contain enough information to be able to cover all the fields
* of struct v4l2_plane at videodev2.h
*/
struct vb2_plane {
void *mem_priv;
struct dma_buf *dbuf;
unsigned int dbuf_mapped;
unsigned int bytesused;
unsigned int length;
unsigned int min_length;
union {
unsigned int offset;
unsigned long userptr;
int fd;
} m;
unsigned int data_offset;
};
/**
* enum vb2_io_modes - queue access methods
* @VB2_MMAP: driver supports MMAP with streaming API
* @VB2_USERPTR: driver supports USERPTR with streaming API
* @VB2_READ: driver supports read() style access
* @VB2_WRITE: driver supports write() style access
* @VB2_DMABUF: driver supports DMABUF with streaming API
*/
enum vb2_io_modes {
VB2_MMAP = (1 << 0),
VB2_USERPTR = (1 << 1),
VB2_READ = (1 << 2),
VB2_WRITE = (1 << 3),
VB2_DMABUF = (1 << 4),
};
/**
* enum vb2_buffer_state - current video buffer state
* @VB2_BUF_STATE_DEQUEUED: buffer under userspace control
* @VB2_BUF_STATE_PREPARING: buffer is being prepared in videobuf
* @VB2_BUF_STATE_PREPARED: buffer prepared in videobuf and by the driver
* @VB2_BUF_STATE_QUEUED: buffer queued in videobuf, but not in driver
* @VB2_BUF_STATE_REQUEUEING: re-queue a buffer to the driver
* @VB2_BUF_STATE_ACTIVE: buffer queued in driver and possibly used
* in a hardware operation
* @VB2_BUF_STATE_DONE: buffer returned from driver to videobuf, but
* not yet dequeued to userspace
* @VB2_BUF_STATE_ERROR: same as above, but the operation on the buffer
* has ended with an error, which will be reported
* to the userspace when it is dequeued
*/
enum vb2_buffer_state {
VB2_BUF_STATE_DEQUEUED,
VB2_BUF_STATE_PREPARING,
VB2_BUF_STATE_PREPARED,
VB2_BUF_STATE_QUEUED,
VB2_BUF_STATE_REQUEUEING,
VB2_BUF_STATE_ACTIVE,
VB2_BUF_STATE_DONE,
VB2_BUF_STATE_ERROR,
};
struct vb2_queue;
/**
* struct vb2_buffer - represents a video buffer
* @vb2_queue: the queue to which this driver belongs
* @index: id number of the buffer
* @type: buffer type
* @memory: the method, in which the actual data is passed
* @num_planes: number of planes in the buffer
* on an internal driver queue
* @planes: private per-plane information; do not change
* @timestamp: frame timestamp in ns
*/
struct vb2_buffer {
struct vb2_queue *vb2_queue;
unsigned int index;
unsigned int type;
unsigned int memory;
unsigned int num_planes;
struct vb2_plane planes[VB2_MAX_PLANES];
u64 timestamp;
/* private: internal use only
*
* state: current buffer state; do not change
* queued_entry: entry on the queued buffers list, which holds
* all buffers queued from userspace
* done_entry: entry on the list that stores all buffers ready
* to be dequeued to userspace
*/
enum vb2_buffer_state state;
struct list_head queued_entry;
struct list_head done_entry;
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* Counters for how often these buffer-related ops are
* called. Used to check for unbalanced ops.
*/
u32 cnt_mem_alloc;
u32 cnt_mem_put;
u32 cnt_mem_get_dmabuf;
u32 cnt_mem_get_userptr;
u32 cnt_mem_put_userptr;
u32 cnt_mem_prepare;
u32 cnt_mem_finish;
u32 cnt_mem_attach_dmabuf;
u32 cnt_mem_detach_dmabuf;
u32 cnt_mem_map_dmabuf;
u32 cnt_mem_unmap_dmabuf;
u32 cnt_mem_vaddr;
u32 cnt_mem_cookie;
u32 cnt_mem_num_users;
u32 cnt_mem_mmap;
u32 cnt_buf_init;
u32 cnt_buf_prepare;
u32 cnt_buf_finish;
u32 cnt_buf_cleanup;
u32 cnt_buf_queue;
/* This counts the number of calls to vb2_buffer_done() */
u32 cnt_buf_done;
#endif
};
/**
* struct vb2_ops - driver-specific callbacks
*
* @queue_setup: called from VIDIOC_REQBUFS and VIDIOC_CREATE_BUFS
* handlers before memory allocation. It can be called
* twice: if the original number of requested buffers
* could not be allocated, then it will be called a
* second time with the actually allocated number of
* buffers to verify if that is OK.
* The driver should return the required number of buffers
* in *num_buffers, the required number of planes per
* buffer in *num_planes, the size of each plane should be
* set in the sizes[] array and optional per-plane
* allocator specific context in the alloc_ctxs[] array.
* When called from VIDIOC_REQBUFS, *num_planes == 0, the
* driver has to use the currently configured format to
* determine the plane sizes and *num_buffers is the total
* number of buffers that are being allocated. When called
* from VIDIOC_CREATE_BUFS, *num_planes != 0 and it
* describes the requested number of planes and sizes[]
* contains the requested plane sizes. If either
* *num_planes or the requested sizes are invalid callback
* must return -EINVAL. In this case *num_buffers are
* being allocated additionally to q->num_buffers.
* @wait_prepare: release any locks taken while calling vb2 functions;
* it is called before an ioctl needs to wait for a new
* buffer to arrive; required to avoid a deadlock in
* blocking access type.
* @wait_finish: reacquire all locks released in the previous callback;
* required to continue operation after sleeping while
* waiting for a new buffer to arrive.
* @buf_init: called once after allocating a buffer (in MMAP case)
* or after acquiring a new USERPTR buffer; drivers may
* perform additional buffer-related initialization;
* initialization failure (return != 0) will prevent
* queue setup from completing successfully; optional.
* @buf_prepare: called every time the buffer is queued from userspace
* and from the VIDIOC_PREPARE_BUF ioctl; drivers may
* perform any initialization required before each
* hardware operation in this callback; drivers can
* access/modify the buffer here as it is still synced for
* the CPU; drivers that support VIDIOC_CREATE_BUFS must
* also validate the buffer size; if an error is returned,
* the buffer will not be queued in driver; optional.
* @buf_finish: called before every dequeue of the buffer back to
* userspace; the buffer is synced for the CPU, so drivers
* can access/modify the buffer contents; drivers may
* perform any operations required before userspace
* accesses the buffer; optional. The buffer state can be
* one of the following: DONE and ERROR occur while
* streaming is in progress, and the PREPARED state occurs
* when the queue has been canceled and all pending
* buffers are being returned to their default DEQUEUED
* state. Typically you only have to do something if the
* state is VB2_BUF_STATE_DONE, since in all other cases
* the buffer contents will be ignored anyway.
* @buf_cleanup: called once before the buffer is freed; drivers may
* perform any additional cleanup; optional.
* @start_streaming: called once to enter 'streaming' state; the driver may
* receive buffers with @buf_queue callback before
* @start_streaming is called; the driver gets the number
* of already queued buffers in count parameter; driver
* can return an error if hardware fails, in that case all
* buffers that have been already given by the @buf_queue
* callback are to be returned by the driver by calling
* @vb2_buffer_done(VB2_BUF_STATE_QUEUED).
* If you need a minimum number of buffers before you can
* start streaming, then set @min_buffers_needed in the
* vb2_queue structure. If that is non-zero then
* start_streaming won't be called until at least that
* many buffers have been queued up by userspace.
* @stop_streaming: called when 'streaming' state must be disabled; driver
* should stop any DMA transactions or wait until they
* finish and give back all buffers it got from buf_queue()
* callback by calling @vb2_buffer_done() with either
* VB2_BUF_STATE_DONE or VB2_BUF_STATE_ERROR; may use
* vb2_wait_for_all_buffers() function
* @buf_queue: passes buffer vb to the driver; driver may start
* hardware operation on this buffer; driver should give
* the buffer back by calling vb2_buffer_done() function;
* it is allways called after calling STREAMON ioctl;
* might be called before start_streaming callback if user
* pre-queued buffers before calling STREAMON.
*/
struct vb2_ops {
int (*queue_setup)(struct vb2_queue *q,
unsigned int *num_buffers, unsigned int *num_planes,
unsigned int sizes[], void *alloc_ctxs[]);
void (*wait_prepare)(struct vb2_queue *q);
void (*wait_finish)(struct vb2_queue *q);
int (*buf_init)(struct vb2_buffer *vb);
int (*buf_prepare)(struct vb2_buffer *vb);
void (*buf_finish)(struct vb2_buffer *vb);
void (*buf_cleanup)(struct vb2_buffer *vb);
int (*start_streaming)(struct vb2_queue *q, unsigned int count);
void (*stop_streaming)(struct vb2_queue *q);
void (*buf_queue)(struct vb2_buffer *vb);
};
/**
* struct vb2_ops - driver-specific callbacks
*
* @fill_user_buffer: given a vb2_buffer fill in the userspace structure.
* For V4L2 this is a struct v4l2_buffer.
* @fill_vb2_buffer: given a userspace structure, fill in the vb2_buffer.
* If the userspace structure is invalid, then this op
* will return an error.
* @copy_timestamp: copy the timestamp from a userspace structure to
* the vb2_buffer struct.
*/
struct vb2_buf_ops {
void (*fill_user_buffer)(struct vb2_buffer *vb, void *pb);
int (*fill_vb2_buffer)(struct vb2_buffer *vb, const void *pb,
struct vb2_plane *planes);
void (*copy_timestamp)(struct vb2_buffer *vb, const void *pb);
};
/**
* struct vb2_queue - a videobuf queue
*
* @type: private buffer type whose content is defined by the vb2-core
* caller. For example, for V4L2, it should match
* the V4L2_BUF_TYPE_* in include/uapi/linux/videodev2.h
* @io_modes: supported io methods (see vb2_io_modes enum)
* @fileio_read_once: report EOF after reading the first buffer
* @fileio_write_immediately: queue buffer after each write() call
* @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver
* @lock: pointer to a mutex that protects the vb2_queue struct. The
* driver can set this to a mutex to let the v4l2 core serialize
* the queuing ioctls. If the driver wants to handle locking
* itself, then this should be set to NULL. This lock is not used
* by the videobuf2 core API.
* @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
* that called reqbufs, create_buffers or started fileio.
* This field is not used by the videobuf2 core API, but it allows
* drivers to easily associate an owner filehandle with the queue.
* @ops: driver-specific callbacks
* @mem_ops: memory allocator specific callbacks
* @buf_ops: callbacks to deliver buffer information
* between user-space and kernel-space
* @drv_priv: driver private data
* @buf_struct_size: size of the driver-specific buffer structure;
* "0" indicates the driver doesn't want to use a custom buffer
* structure type. for example, sizeof(struct vb2_v4l2_buffer)
* will be used for v4l2.
* @timestamp_flags: Timestamp flags; V4L2_BUF_FLAG_TIMESTAMP_* and
* V4L2_BUF_FLAG_TSTAMP_SRC_*
* @gfp_flags: additional gfp flags used when allocating the buffers.
* Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
* to force the buffer allocation to a specific memory zone.
[media] vb2: only call start_streaming if sufficient buffers are queued In commit 02f142ecd24aaf891324ffba8527284c1731b561 support was added to start_streaming to return -ENOBUFS if insufficient buffers were queued for the DMA engine to start. The vb2 core would attempt calling start_streaming again if another buffer would be queued up. Later analysis uncovered problems with the queue management if start_streaming would return an error: the buffers are enqueued to the driver before the start_streaming op is called, so after an error they are never returned to the vb2 core. The solution for this is to let the driver return them to the vb2 core in case of an error while starting the DMA engine. However, in the case of -ENOBUFS that would be weird: it is not a real error, it just says that more buffers are needed. Requiring start_streaming to give them back only to have them requeued again the next time the application calls QBUF is inefficient. This patch changes this mechanism: it adds a 'min_buffers_needed' field to vb2_queue that drivers can set with the minimum number of buffers required to start the DMA engine. The start_streaming op is only called if enough buffers are queued. The -ENOBUFS handling has been dropped in favor of this new method. Drivers are expected to return buffers back to vb2 core with state QUEUED if start_streaming would return an error. The vb2 core checks for this and produces a warning if that didn't happen and it will forcefully reclaim such buffers to ensure that the internal vb2 core state remains consistent and all buffer-related resources have been correctly freed and all op calls have been balanced. __reqbufs() has been updated to check that at least min_buffers_needed buffers could be allocated. If fewer buffers were allocated then __reqbufs will free what was allocated and return -ENOMEM. Based on a suggestion from Pawel Osciak. __create_bufs() doesn't do that check, since the use of __create_bufs assumes some advance scenario where the user might want more control. Instead streamon will check if enough buffers were allocated to prevent streaming with fewer than the minimum required number of buffers. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-24 17:51:03 +01:00
* @min_buffers_needed: the minimum number of buffers needed before
* start_streaming() can be called. Used when a DMA engine
* cannot be started unless at least this number of buffers
* have been queued into the driver.
*/
/*
* Private elements (won't appear at the DocBook):
[media] videobuf2: fix lockdep warning The following lockdep warning has been there ever since commit a517cca6b24fc54ac209e44118ec8962051662e3 one year ago: [ 403.117947] ====================================================== [ 403.117949] [ INFO: possible circular locking dependency detected ] [ 403.117953] 3.16.0-rc6-test-media #961 Not tainted [ 403.117954] ------------------------------------------------------- [ 403.117956] v4l2-ctl/15377 is trying to acquire lock: [ 403.117959] (&dev->mutex#3){+.+.+.}, at: [<ffffffffa005a6c3>] vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.117974] [ 403.117974] but task is already holding lock: [ 403.117976] (&mm->mmap_sem){++++++}, at: [<ffffffff8118291f>] vm_mmap_pgoff+0x6f/0xc0 [ 403.117987] [ 403.117987] which lock already depends on the new lock. [ 403.117987] [ 403.117990] [ 403.117990] the existing dependency chain (in reverse order) is: [ 403.117992] [ 403.117992] -> #1 (&mm->mmap_sem){++++++}: [ 403.117997] [<ffffffff810d733c>] validate_chain.isra.39+0x5fc/0x9a0 [ 403.118006] [<ffffffff810d8bc3>] __lock_acquire+0x4d3/0xd30 [ 403.118010] [<ffffffff810d9da7>] lock_acquire+0xa7/0x160 [ 403.118014] [<ffffffff8118c9ec>] might_fault+0x7c/0xb0 [ 403.118018] [<ffffffffa0028a25>] video_usercopy+0x425/0x610 [videodev] [ 403.118028] [<ffffffffa0028c25>] video_ioctl2+0x15/0x20 [videodev] [ 403.118034] [<ffffffffa0022764>] v4l2_ioctl+0x184/0x1a0 [videodev] [ 403.118040] [<ffffffff811d77d0>] do_vfs_ioctl+0x2f0/0x4f0 [ 403.118307] [<ffffffff811d7a51>] SyS_ioctl+0x81/0xa0 [ 403.118311] [<ffffffff8199dc69>] system_call_fastpath+0x16/0x1b [ 403.118319] [ 403.118319] -> #0 (&dev->mutex#3){+.+.+.}: [ 403.118324] [<ffffffff810d6a96>] check_prevs_add+0x746/0x9f0 [ 403.118329] [<ffffffff810d733c>] validate_chain.isra.39+0x5fc/0x9a0 [ 403.118333] [<ffffffff810d8bc3>] __lock_acquire+0x4d3/0xd30 [ 403.118336] [<ffffffff810d9da7>] lock_acquire+0xa7/0x160 [ 403.118340] [<ffffffff81999664>] mutex_lock_interruptible_nested+0x64/0x640 [ 403.118344] [<ffffffffa005a6c3>] vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118349] [<ffffffffa0022122>] v4l2_mmap+0x62/0xa0 [videodev] [ 403.118354] [<ffffffff81197270>] mmap_region+0x3d0/0x5d0 [ 403.118359] [<ffffffff8119778d>] do_mmap_pgoff+0x31d/0x400 [ 403.118363] [<ffffffff81182940>] vm_mmap_pgoff+0x90/0xc0 [ 403.118366] [<ffffffff81195cef>] SyS_mmap_pgoff+0x1df/0x2a0 [ 403.118369] [<ffffffff810085c2>] SyS_mmap+0x22/0x30 [ 403.118376] [<ffffffff8199dc69>] system_call_fastpath+0x16/0x1b [ 403.118381] [ 403.118381] other info that might help us debug this: [ 403.118381] [ 403.118383] Possible unsafe locking scenario: [ 403.118383] [ 403.118385] CPU0 CPU1 [ 403.118387] ---- ---- [ 403.118388] lock(&mm->mmap_sem); [ 403.118391] lock(&dev->mutex#3); [ 403.118394] lock(&mm->mmap_sem); [ 403.118397] lock(&dev->mutex#3); [ 403.118400] [ 403.118400] *** DEADLOCK *** [ 403.118400] [ 403.118403] 1 lock held by v4l2-ctl/15377: [ 403.118405] #0: (&mm->mmap_sem){++++++}, at: [<ffffffff8118291f>] vm_mmap_pgoff+0x6f/0xc0 [ 403.118411] [ 403.118411] stack backtrace: [ 403.118415] CPU: 0 PID: 15377 Comm: v4l2-ctl Not tainted 3.16.0-rc6-test-media #961 [ 403.118418] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013 [ 403.118420] ffffffff82a6c9d0 ffff8800af37fb00 ffffffff819916a2 ffffffff82a6c9d0 [ 403.118425] ffff8800af37fb40 ffffffff810d5715 ffff8802308e4200 0000000000000000 [ 403.118429] ffff8802308e4a48 ffff8802308e4a48 ffff8802308e4200 0000000000000001 [ 403.118433] Call Trace: [ 403.118441] [<ffffffff819916a2>] dump_stack+0x4e/0x7a [ 403.118445] [<ffffffff810d5715>] print_circular_bug+0x1d5/0x2a0 [ 403.118449] [<ffffffff810d6a96>] check_prevs_add+0x746/0x9f0 [ 403.118455] [<ffffffff8119c172>] ? find_vmap_area+0x42/0x70 [ 403.118459] [<ffffffff810d733c>] validate_chain.isra.39+0x5fc/0x9a0 [ 403.118463] [<ffffffff810d8bc3>] __lock_acquire+0x4d3/0xd30 [ 403.118468] [<ffffffff810d9da7>] lock_acquire+0xa7/0x160 [ 403.118472] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118476] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118480] [<ffffffff81999664>] mutex_lock_interruptible_nested+0x64/0x640 [ 403.118484] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118488] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118493] [<ffffffff810d8055>] ? mark_held_locks+0x75/0xa0 [ 403.118497] [<ffffffffa005a6c3>] vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118502] [<ffffffffa0022122>] v4l2_mmap+0x62/0xa0 [videodev] [ 403.118506] [<ffffffff81197270>] mmap_region+0x3d0/0x5d0 [ 403.118510] [<ffffffff8119778d>] do_mmap_pgoff+0x31d/0x400 [ 403.118513] [<ffffffff81182940>] vm_mmap_pgoff+0x90/0xc0 [ 403.118517] [<ffffffff81195cef>] SyS_mmap_pgoff+0x1df/0x2a0 [ 403.118521] [<ffffffff810085c2>] SyS_mmap+0x22/0x30 [ 403.118525] [<ffffffff8199dc69>] system_call_fastpath+0x16/0x1b The reason is that vb2_fop_mmap and vb2_fop_get_unmapped_area take the core lock while they are called with the mmap_sem semaphore held. But elsewhere in the code the core lock is taken first but calls to copy_to/from_user() can take the mmap_sem semaphore as well, potentially causing a classical A-B/B-A deadlock. However, the mmap/get_unmapped_area calls really shouldn't take the core lock at all. So what would happen if they don't take the core lock anymore? There are two situations that need to be taken into account: calling mmap while new buffers are being added and calling mmap while buffers are being deleted. The first case works almost fine without a lock: in all cases mmap relies on correctly filled-in q->num_buffers/q->num_planes values and those are only updated by reqbufs and create_buffers *after* any new buffers have been initialized completely. Except in one case: if an error occurred while allocating the buffers it will increase num_buffers and rely on __vb2_queue_free to decrease it again. So there is a short period where the buffer information may be wrong. The second case definitely does pose a problem: buffers may be in the process of being deleted, without the internal structure being updated. In order to fix this a new mutex is added to vb2_queue that is taken when buffers are allocated or deleted, and in vb2_mmap. That way vb2_mmap won't get stale buffer data. Note that this is a problem only for MEMORY_MMAP, so even though __qbuf_userptr and __qbuf_dmabuf also mess around with buffers (mem_priv in particular), this doesn't clash with vb2_mmap or vb2_get_unmapped_area since those are MMAP specific. As an additional bonus the hack in __buf_prepare, the USERPTR case, can be removed as well since mmap() no longer takes the core lock. All in all a much cleaner solution. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-08-07 08:47:14 +02:00
* @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
* @memory: current memory type used
* @bufs: videobuf buffer structures
* @num_buffers: number of allocated/used buffers
* @queued_list: list of buffers currently queued from userspace
[media] vb2: only call start_streaming if sufficient buffers are queued In commit 02f142ecd24aaf891324ffba8527284c1731b561 support was added to start_streaming to return -ENOBUFS if insufficient buffers were queued for the DMA engine to start. The vb2 core would attempt calling start_streaming again if another buffer would be queued up. Later analysis uncovered problems with the queue management if start_streaming would return an error: the buffers are enqueued to the driver before the start_streaming op is called, so after an error they are never returned to the vb2 core. The solution for this is to let the driver return them to the vb2 core in case of an error while starting the DMA engine. However, in the case of -ENOBUFS that would be weird: it is not a real error, it just says that more buffers are needed. Requiring start_streaming to give them back only to have them requeued again the next time the application calls QBUF is inefficient. This patch changes this mechanism: it adds a 'min_buffers_needed' field to vb2_queue that drivers can set with the minimum number of buffers required to start the DMA engine. The start_streaming op is only called if enough buffers are queued. The -ENOBUFS handling has been dropped in favor of this new method. Drivers are expected to return buffers back to vb2 core with state QUEUED if start_streaming would return an error. The vb2 core checks for this and produces a warning if that didn't happen and it will forcefully reclaim such buffers to ensure that the internal vb2 core state remains consistent and all buffer-related resources have been correctly freed and all op calls have been balanced. __reqbufs() has been updated to check that at least min_buffers_needed buffers could be allocated. If fewer buffers were allocated then __reqbufs will free what was allocated and return -ENOMEM. Based on a suggestion from Pawel Osciak. __create_bufs() doesn't do that check, since the use of __create_bufs assumes some advance scenario where the user might want more control. Instead streamon will check if enough buffers were allocated to prevent streaming with fewer than the minimum required number of buffers. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-24 17:51:03 +01:00
* @queued_count: number of buffers queued and ready for streaming.
* @owned_by_drv_count: number of buffers owned by the driver
* @done_list: list of buffers ready to be dequeued to userspace
* @done_lock: lock to protect done_list list
* @done_wq: waitqueue for processes waiting for buffers ready to be dequeued
* @alloc_ctx: memory type/allocator-specific contexts for each plane
* @streaming: current streaming state
[media] vb2: only call start_streaming if sufficient buffers are queued In commit 02f142ecd24aaf891324ffba8527284c1731b561 support was added to start_streaming to return -ENOBUFS if insufficient buffers were queued for the DMA engine to start. The vb2 core would attempt calling start_streaming again if another buffer would be queued up. Later analysis uncovered problems with the queue management if start_streaming would return an error: the buffers are enqueued to the driver before the start_streaming op is called, so after an error they are never returned to the vb2 core. The solution for this is to let the driver return them to the vb2 core in case of an error while starting the DMA engine. However, in the case of -ENOBUFS that would be weird: it is not a real error, it just says that more buffers are needed. Requiring start_streaming to give them back only to have them requeued again the next time the application calls QBUF is inefficient. This patch changes this mechanism: it adds a 'min_buffers_needed' field to vb2_queue that drivers can set with the minimum number of buffers required to start the DMA engine. The start_streaming op is only called if enough buffers are queued. The -ENOBUFS handling has been dropped in favor of this new method. Drivers are expected to return buffers back to vb2 core with state QUEUED if start_streaming would return an error. The vb2 core checks for this and produces a warning if that didn't happen and it will forcefully reclaim such buffers to ensure that the internal vb2 core state remains consistent and all buffer-related resources have been correctly freed and all op calls have been balanced. __reqbufs() has been updated to check that at least min_buffers_needed buffers could be allocated. If fewer buffers were allocated then __reqbufs will free what was allocated and return -ENOMEM. Based on a suggestion from Pawel Osciak. __create_bufs() doesn't do that check, since the use of __create_bufs assumes some advance scenario where the user might want more control. Instead streamon will check if enough buffers were allocated to prevent streaming with fewer than the minimum required number of buffers. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-24 17:51:03 +01:00
* @start_streaming_called: start_streaming() was called successfully and we
* started streaming.
* @error: a fatal error occurred on the queue
* @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
* buffers. Only set for capture queues if qbuf has not yet been
* called since poll() needs to return POLLERR in that situation.
* @is_multiplanar: set if buffer type is multiplanar
* @is_output: set if buffer type is output
* @copy_timestamp: set if vb2-core should set timestamps
* @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
* last decoded buffer was already dequeued. Set for capture queues
* when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
* @fileio: file io emulator internal data, used only if emulator is active
* @threadio: thread io internal data, used only if thread is active
*/
struct vb2_queue {
unsigned int type;
unsigned int io_modes;
unsigned fileio_read_once:1;
unsigned fileio_write_immediately:1;
unsigned allow_zero_bytesused:1;
struct mutex *lock;
void *owner;
const struct vb2_ops *ops;
const struct vb2_mem_ops *mem_ops;
const struct vb2_buf_ops *buf_ops;
void *drv_priv;
unsigned int buf_struct_size;
u32 timestamp_flags;
gfp_t gfp_flags;
[media] vb2: only call start_streaming if sufficient buffers are queued In commit 02f142ecd24aaf891324ffba8527284c1731b561 support was added to start_streaming to return -ENOBUFS if insufficient buffers were queued for the DMA engine to start. The vb2 core would attempt calling start_streaming again if another buffer would be queued up. Later analysis uncovered problems with the queue management if start_streaming would return an error: the buffers are enqueued to the driver before the start_streaming op is called, so after an error they are never returned to the vb2 core. The solution for this is to let the driver return them to the vb2 core in case of an error while starting the DMA engine. However, in the case of -ENOBUFS that would be weird: it is not a real error, it just says that more buffers are needed. Requiring start_streaming to give them back only to have them requeued again the next time the application calls QBUF is inefficient. This patch changes this mechanism: it adds a 'min_buffers_needed' field to vb2_queue that drivers can set with the minimum number of buffers required to start the DMA engine. The start_streaming op is only called if enough buffers are queued. The -ENOBUFS handling has been dropped in favor of this new method. Drivers are expected to return buffers back to vb2 core with state QUEUED if start_streaming would return an error. The vb2 core checks for this and produces a warning if that didn't happen and it will forcefully reclaim such buffers to ensure that the internal vb2 core state remains consistent and all buffer-related resources have been correctly freed and all op calls have been balanced. __reqbufs() has been updated to check that at least min_buffers_needed buffers could be allocated. If fewer buffers were allocated then __reqbufs will free what was allocated and return -ENOMEM. Based on a suggestion from Pawel Osciak. __create_bufs() doesn't do that check, since the use of __create_bufs assumes some advance scenario where the user might want more control. Instead streamon will check if enough buffers were allocated to prevent streaming with fewer than the minimum required number of buffers. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-24 17:51:03 +01:00
u32 min_buffers_needed;
/* private: internal use only */
[media] videobuf2: fix lockdep warning The following lockdep warning has been there ever since commit a517cca6b24fc54ac209e44118ec8962051662e3 one year ago: [ 403.117947] ====================================================== [ 403.117949] [ INFO: possible circular locking dependency detected ] [ 403.117953] 3.16.0-rc6-test-media #961 Not tainted [ 403.117954] ------------------------------------------------------- [ 403.117956] v4l2-ctl/15377 is trying to acquire lock: [ 403.117959] (&dev->mutex#3){+.+.+.}, at: [<ffffffffa005a6c3>] vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.117974] [ 403.117974] but task is already holding lock: [ 403.117976] (&mm->mmap_sem){++++++}, at: [<ffffffff8118291f>] vm_mmap_pgoff+0x6f/0xc0 [ 403.117987] [ 403.117987] which lock already depends on the new lock. [ 403.117987] [ 403.117990] [ 403.117990] the existing dependency chain (in reverse order) is: [ 403.117992] [ 403.117992] -> #1 (&mm->mmap_sem){++++++}: [ 403.117997] [<ffffffff810d733c>] validate_chain.isra.39+0x5fc/0x9a0 [ 403.118006] [<ffffffff810d8bc3>] __lock_acquire+0x4d3/0xd30 [ 403.118010] [<ffffffff810d9da7>] lock_acquire+0xa7/0x160 [ 403.118014] [<ffffffff8118c9ec>] might_fault+0x7c/0xb0 [ 403.118018] [<ffffffffa0028a25>] video_usercopy+0x425/0x610 [videodev] [ 403.118028] [<ffffffffa0028c25>] video_ioctl2+0x15/0x20 [videodev] [ 403.118034] [<ffffffffa0022764>] v4l2_ioctl+0x184/0x1a0 [videodev] [ 403.118040] [<ffffffff811d77d0>] do_vfs_ioctl+0x2f0/0x4f0 [ 403.118307] [<ffffffff811d7a51>] SyS_ioctl+0x81/0xa0 [ 403.118311] [<ffffffff8199dc69>] system_call_fastpath+0x16/0x1b [ 403.118319] [ 403.118319] -> #0 (&dev->mutex#3){+.+.+.}: [ 403.118324] [<ffffffff810d6a96>] check_prevs_add+0x746/0x9f0 [ 403.118329] [<ffffffff810d733c>] validate_chain.isra.39+0x5fc/0x9a0 [ 403.118333] [<ffffffff810d8bc3>] __lock_acquire+0x4d3/0xd30 [ 403.118336] [<ffffffff810d9da7>] lock_acquire+0xa7/0x160 [ 403.118340] [<ffffffff81999664>] mutex_lock_interruptible_nested+0x64/0x640 [ 403.118344] [<ffffffffa005a6c3>] vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118349] [<ffffffffa0022122>] v4l2_mmap+0x62/0xa0 [videodev] [ 403.118354] [<ffffffff81197270>] mmap_region+0x3d0/0x5d0 [ 403.118359] [<ffffffff8119778d>] do_mmap_pgoff+0x31d/0x400 [ 403.118363] [<ffffffff81182940>] vm_mmap_pgoff+0x90/0xc0 [ 403.118366] [<ffffffff81195cef>] SyS_mmap_pgoff+0x1df/0x2a0 [ 403.118369] [<ffffffff810085c2>] SyS_mmap+0x22/0x30 [ 403.118376] [<ffffffff8199dc69>] system_call_fastpath+0x16/0x1b [ 403.118381] [ 403.118381] other info that might help us debug this: [ 403.118381] [ 403.118383] Possible unsafe locking scenario: [ 403.118383] [ 403.118385] CPU0 CPU1 [ 403.118387] ---- ---- [ 403.118388] lock(&mm->mmap_sem); [ 403.118391] lock(&dev->mutex#3); [ 403.118394] lock(&mm->mmap_sem); [ 403.118397] lock(&dev->mutex#3); [ 403.118400] [ 403.118400] *** DEADLOCK *** [ 403.118400] [ 403.118403] 1 lock held by v4l2-ctl/15377: [ 403.118405] #0: (&mm->mmap_sem){++++++}, at: [<ffffffff8118291f>] vm_mmap_pgoff+0x6f/0xc0 [ 403.118411] [ 403.118411] stack backtrace: [ 403.118415] CPU: 0 PID: 15377 Comm: v4l2-ctl Not tainted 3.16.0-rc6-test-media #961 [ 403.118418] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013 [ 403.118420] ffffffff82a6c9d0 ffff8800af37fb00 ffffffff819916a2 ffffffff82a6c9d0 [ 403.118425] ffff8800af37fb40 ffffffff810d5715 ffff8802308e4200 0000000000000000 [ 403.118429] ffff8802308e4a48 ffff8802308e4a48 ffff8802308e4200 0000000000000001 [ 403.118433] Call Trace: [ 403.118441] [<ffffffff819916a2>] dump_stack+0x4e/0x7a [ 403.118445] [<ffffffff810d5715>] print_circular_bug+0x1d5/0x2a0 [ 403.118449] [<ffffffff810d6a96>] check_prevs_add+0x746/0x9f0 [ 403.118455] [<ffffffff8119c172>] ? find_vmap_area+0x42/0x70 [ 403.118459] [<ffffffff810d733c>] validate_chain.isra.39+0x5fc/0x9a0 [ 403.118463] [<ffffffff810d8bc3>] __lock_acquire+0x4d3/0xd30 [ 403.118468] [<ffffffff810d9da7>] lock_acquire+0xa7/0x160 [ 403.118472] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118476] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118480] [<ffffffff81999664>] mutex_lock_interruptible_nested+0x64/0x640 [ 403.118484] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118488] [<ffffffffa005a6c3>] ? vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118493] [<ffffffff810d8055>] ? mark_held_locks+0x75/0xa0 [ 403.118497] [<ffffffffa005a6c3>] vb2_fop_mmap+0x33/0x90 [videobuf2_core] [ 403.118502] [<ffffffffa0022122>] v4l2_mmap+0x62/0xa0 [videodev] [ 403.118506] [<ffffffff81197270>] mmap_region+0x3d0/0x5d0 [ 403.118510] [<ffffffff8119778d>] do_mmap_pgoff+0x31d/0x400 [ 403.118513] [<ffffffff81182940>] vm_mmap_pgoff+0x90/0xc0 [ 403.118517] [<ffffffff81195cef>] SyS_mmap_pgoff+0x1df/0x2a0 [ 403.118521] [<ffffffff810085c2>] SyS_mmap+0x22/0x30 [ 403.118525] [<ffffffff8199dc69>] system_call_fastpath+0x16/0x1b The reason is that vb2_fop_mmap and vb2_fop_get_unmapped_area take the core lock while they are called with the mmap_sem semaphore held. But elsewhere in the code the core lock is taken first but calls to copy_to/from_user() can take the mmap_sem semaphore as well, potentially causing a classical A-B/B-A deadlock. However, the mmap/get_unmapped_area calls really shouldn't take the core lock at all. So what would happen if they don't take the core lock anymore? There are two situations that need to be taken into account: calling mmap while new buffers are being added and calling mmap while buffers are being deleted. The first case works almost fine without a lock: in all cases mmap relies on correctly filled-in q->num_buffers/q->num_planes values and those are only updated by reqbufs and create_buffers *after* any new buffers have been initialized completely. Except in one case: if an error occurred while allocating the buffers it will increase num_buffers and rely on __vb2_queue_free to decrease it again. So there is a short period where the buffer information may be wrong. The second case definitely does pose a problem: buffers may be in the process of being deleted, without the internal structure being updated. In order to fix this a new mutex is added to vb2_queue that is taken when buffers are allocated or deleted, and in vb2_mmap. That way vb2_mmap won't get stale buffer data. Note that this is a problem only for MEMORY_MMAP, so even though __qbuf_userptr and __qbuf_dmabuf also mess around with buffers (mem_priv in particular), this doesn't clash with vb2_mmap or vb2_get_unmapped_area since those are MMAP specific. As an additional bonus the hack in __buf_prepare, the USERPTR case, can be removed as well since mmap() no longer takes the core lock. All in all a much cleaner solution. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-08-07 08:47:14 +02:00
struct mutex mmap_lock;
unsigned int memory;
struct vb2_buffer *bufs[VB2_MAX_FRAME];
unsigned int num_buffers;
struct list_head queued_list;
[media] vb2: only call start_streaming if sufficient buffers are queued In commit 02f142ecd24aaf891324ffba8527284c1731b561 support was added to start_streaming to return -ENOBUFS if insufficient buffers were queued for the DMA engine to start. The vb2 core would attempt calling start_streaming again if another buffer would be queued up. Later analysis uncovered problems with the queue management if start_streaming would return an error: the buffers are enqueued to the driver before the start_streaming op is called, so after an error they are never returned to the vb2 core. The solution for this is to let the driver return them to the vb2 core in case of an error while starting the DMA engine. However, in the case of -ENOBUFS that would be weird: it is not a real error, it just says that more buffers are needed. Requiring start_streaming to give them back only to have them requeued again the next time the application calls QBUF is inefficient. This patch changes this mechanism: it adds a 'min_buffers_needed' field to vb2_queue that drivers can set with the minimum number of buffers required to start the DMA engine. The start_streaming op is only called if enough buffers are queued. The -ENOBUFS handling has been dropped in favor of this new method. Drivers are expected to return buffers back to vb2 core with state QUEUED if start_streaming would return an error. The vb2 core checks for this and produces a warning if that didn't happen and it will forcefully reclaim such buffers to ensure that the internal vb2 core state remains consistent and all buffer-related resources have been correctly freed and all op calls have been balanced. __reqbufs() has been updated to check that at least min_buffers_needed buffers could be allocated. If fewer buffers were allocated then __reqbufs will free what was allocated and return -ENOMEM. Based on a suggestion from Pawel Osciak. __create_bufs() doesn't do that check, since the use of __create_bufs assumes some advance scenario where the user might want more control. Instead streamon will check if enough buffers were allocated to prevent streaming with fewer than the minimum required number of buffers. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-24 17:51:03 +01:00
unsigned int queued_count;
atomic_t owned_by_drv_count;
struct list_head done_list;
spinlock_t done_lock;
wait_queue_head_t done_wq;
void *alloc_ctx[VB2_MAX_PLANES];
unsigned int streaming:1;
[media] vb2: only call start_streaming if sufficient buffers are queued In commit 02f142ecd24aaf891324ffba8527284c1731b561 support was added to start_streaming to return -ENOBUFS if insufficient buffers were queued for the DMA engine to start. The vb2 core would attempt calling start_streaming again if another buffer would be queued up. Later analysis uncovered problems with the queue management if start_streaming would return an error: the buffers are enqueued to the driver before the start_streaming op is called, so after an error they are never returned to the vb2 core. The solution for this is to let the driver return them to the vb2 core in case of an error while starting the DMA engine. However, in the case of -ENOBUFS that would be weird: it is not a real error, it just says that more buffers are needed. Requiring start_streaming to give them back only to have them requeued again the next time the application calls QBUF is inefficient. This patch changes this mechanism: it adds a 'min_buffers_needed' field to vb2_queue that drivers can set with the minimum number of buffers required to start the DMA engine. The start_streaming op is only called if enough buffers are queued. The -ENOBUFS handling has been dropped in favor of this new method. Drivers are expected to return buffers back to vb2 core with state QUEUED if start_streaming would return an error. The vb2 core checks for this and produces a warning if that didn't happen and it will forcefully reclaim such buffers to ensure that the internal vb2 core state remains consistent and all buffer-related resources have been correctly freed and all op calls have been balanced. __reqbufs() has been updated to check that at least min_buffers_needed buffers could be allocated. If fewer buffers were allocated then __reqbufs will free what was allocated and return -ENOMEM. Based on a suggestion from Pawel Osciak. __create_bufs() doesn't do that check, since the use of __create_bufs assumes some advance scenario where the user might want more control. Instead streamon will check if enough buffers were allocated to prevent streaming with fewer than the minimum required number of buffers. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-02-24 17:51:03 +01:00
unsigned int start_streaming_called:1;
unsigned int error:1;
unsigned int waiting_for_buffers:1;
unsigned int is_multiplanar:1;
unsigned int is_output:1;
unsigned int copy_timestamp:1;
unsigned int last_buffer_dequeued:1;
struct vb2_fileio_data *fileio;
struct vb2_threadio_data *threadio;
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* Counters for how often these queue-related ops are
* called. Used to check for unbalanced ops.
*/
u32 cnt_queue_setup;
u32 cnt_wait_prepare;
u32 cnt_wait_finish;
u32 cnt_start_streaming;
u32 cnt_stop_streaming;
#endif
};
void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no);
void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no);
void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state);
void vb2_discard_done(struct vb2_queue *q);
int vb2_wait_for_all_buffers(struct vb2_queue *q);
void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int *count);
int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int *count, unsigned requested_planes,
const unsigned int requested_sizes[]);
int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
int vb2_core_dqbuf(struct vb2_queue *q, void *pb, bool nonblocking);
int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
unsigned int index, unsigned int plane, unsigned int flags);
int vb2_core_queue_init(struct vb2_queue *q);
void vb2_core_queue_release(struct vb2_queue *q);
void vb2_queue_error(struct vb2_queue *q);
int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
#ifndef CONFIG_MMU
unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
unsigned long addr,
unsigned long len,
unsigned long pgoff,
unsigned long flags);
#endif
unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file,
poll_table *wait);
size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
loff_t *ppos, int nonblock);
size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
loff_t *ppos, int nonblock);
/*
* vb2_thread_fnc - callback function for use with vb2_thread
*
* This is called whenever a buffer is dequeued in the thread.
*/
typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
/**
* vb2_thread_start() - start a thread for the given queue.
* @q: videobuf queue
* @fnc: callback function
* @priv: priv pointer passed to the callback function
* @thread_name:the name of the thread. This will be prefixed with "vb2-".
*
* This starts a thread that will queue and dequeue until an error occurs
* or @vb2_thread_stop is called.
*
* This function should not be used for anything else but the videobuf2-dvb
* support. If you think you have another good use-case for this, then please
* contact the linux-media mailinglist first.
*/
int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
const char *thread_name);
/**
* vb2_thread_stop() - stop the thread for the given queue.
* @q: videobuf queue
*/
int vb2_thread_stop(struct vb2_queue *q);
/**
* vb2_is_streaming() - return streaming status of the queue
* @q: videobuf queue
*/
static inline bool vb2_is_streaming(struct vb2_queue *q)
{
return q->streaming;
}
/**
* vb2_fileio_is_active() - return true if fileio is active.
* @q: videobuf queue
*
* This returns true if read() or write() is used to stream the data
* as opposed to stream I/O. This is almost never an important distinction,
* except in rare cases. One such case is that using read() or write() to
* stream a format using V4L2_FIELD_ALTERNATE is not allowed since there
* is no way you can pass the field information of each buffer to/from
* userspace. A driver that supports this field format should check for
* this in the queue_setup op and reject it if this function returns true.
*/
static inline bool vb2_fileio_is_active(struct vb2_queue *q)
{
return q->fileio;
}
/**
* vb2_is_busy() - return busy status of the queue
* @q: videobuf queue
*
* This function checks if queue has any buffers allocated.
*/
static inline bool vb2_is_busy(struct vb2_queue *q)
{
return (q->num_buffers > 0);
}
/**
* vb2_get_drv_priv() - return driver private data associated with the queue
* @q: videobuf queue
*/
static inline void *vb2_get_drv_priv(struct vb2_queue *q)
{
return q->drv_priv;
}
/**
* vb2_set_plane_payload() - set bytesused for the plane plane_no
* @vb: buffer for which plane payload should be set
* @plane_no: plane number for which payload should be set
* @size: payload in bytes
*/
static inline void vb2_set_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no, unsigned long size)
{
if (plane_no < vb->num_planes)
vb->planes[plane_no].bytesused = size;
}
/**
* vb2_get_plane_payload() - get bytesused for the plane plane_no
* @vb: buffer for which plane payload should be set
* @plane_no: plane number for which payload should be set
*/
static inline unsigned long vb2_get_plane_payload(struct vb2_buffer *vb,
unsigned int plane_no)
{
if (plane_no < vb->num_planes)
return vb->planes[plane_no].bytesused;
return 0;
}
/**
* vb2_plane_size() - return plane size in bytes
* @vb: buffer for which plane size should be returned
* @plane_no: plane number for which size should be returned
*/
static inline unsigned long
vb2_plane_size(struct vb2_buffer *vb, unsigned int plane_no)
{
if (plane_no < vb->num_planes)
return vb->planes[plane_no].length;
return 0;
}
/**
* vb2_start_streaming_called() - return streaming status of driver
* @q: videobuf queue
*/
static inline bool vb2_start_streaming_called(struct vb2_queue *q)
{
return q->start_streaming_called;
}
/**
* vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue
* @q: videobuf queue
*/
static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
{
q->last_buffer_dequeued = false;
}
/*
* The following functions are not part of the vb2 core API, but are useful
* functions for videobuf2-*.
*/
bool vb2_buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb);
int vb2_verify_memory_type(struct vb2_queue *q,
enum vb2_memory memory, unsigned int type);
#endif /* _MEDIA_VIDEOBUF2_CORE_H */