diff options
Diffstat (limited to 'drivers/dma-buf')
| -rw-r--r-- | drivers/dma-buf/Makefile | 1 | ||||
| -rw-r--r-- | drivers/dma-buf/dma-buf.c | 904 | ||||
| -rw-r--r-- | drivers/dma-buf/fence.c | 434 | ||||
| -rw-r--r-- | drivers/dma-buf/reservation.c | 478 | ||||
| -rw-r--r-- | drivers/dma-buf/seqno-fence.c | 73 |
5 files changed, 1890 insertions, 0 deletions
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile new file mode 100644 index 000000000..57a675f90 --- /dev/null +++ b/drivers/dma-buf/Makefile @@ -0,0 +1 @@ +obj-y := dma-buf.o fence.o reservation.o seqno-fence.o diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c new file mode 100644 index 000000000..c5a9138a6 --- /dev/null +++ b/drivers/dma-buf/dma-buf.c @@ -0,0 +1,904 @@ +/* + * Framework for buffer objects that can be shared across devices/subsystems. + * + * Copyright(C) 2011 Linaro Limited. All rights reserved. + * Author: Sumit Semwal <sumit.semwal@ti.com> + * + * Many thanks to linaro-mm-sig list, and specially + * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and + * Daniel Vetter <daniel@ffwll.ch> for their support in creation and + * refining of this idea. + * + * 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, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/dma-buf.h> +#include <linux/fence.h> +#include <linux/anon_inodes.h> +#include <linux/export.h> +#include <linux/debugfs.h> +#include <linux/seq_file.h> +#include <linux/poll.h> +#include <linux/reservation.h> + +static inline int is_dma_buf_file(struct file *); + +struct dma_buf_list { + struct list_head head; + struct mutex lock; +}; + +static struct dma_buf_list db_list; + +static int dma_buf_release(struct inode *inode, struct file *file) +{ + struct dma_buf *dmabuf; + + if (!is_dma_buf_file(file)) + return -EINVAL; + + dmabuf = file->private_data; + + BUG_ON(dmabuf->vmapping_counter); + + /* + * Any fences that a dma-buf poll can wait on should be signaled + * before releasing dma-buf. This is the responsibility of each + * driver that uses the reservation objects. + * + * If you hit this BUG() it means someone dropped their ref to the + * dma-buf while still having pending operation to the buffer. + */ + BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active); + + dmabuf->ops->release(dmabuf); + + mutex_lock(&db_list.lock); + list_del(&dmabuf->list_node); + mutex_unlock(&db_list.lock); + + if (dmabuf->resv == (struct reservation_object *)&dmabuf[1]) + reservation_object_fini(dmabuf->resv); + + kfree(dmabuf); + return 0; +} + +static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) +{ + struct dma_buf *dmabuf; + + if (!is_dma_buf_file(file)) + return -EINVAL; + + dmabuf = file->private_data; + + /* check for overflowing the buffer's size */ + if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) > + dmabuf->size >> PAGE_SHIFT) + return -EINVAL; + + return dmabuf->ops->mmap(dmabuf, vma); +} + +static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) +{ + struct dma_buf *dmabuf; + loff_t base; + + if (!is_dma_buf_file(file)) + return -EBADF; + + dmabuf = file->private_data; + + /* only support discovering the end of the buffer, + but also allow SEEK_SET to maintain the idiomatic + SEEK_END(0), SEEK_CUR(0) pattern */ + if (whence == SEEK_END) + base = dmabuf->size; + else if (whence == SEEK_SET) + base = 0; + else + return -EINVAL; + + if (offset != 0) + return -EINVAL; + + return base + offset; +} + +static void dma_buf_poll_cb(struct fence *fence, struct fence_cb *cb) +{ + struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb; + unsigned long flags; + + spin_lock_irqsave(&dcb->poll->lock, flags); + wake_up_locked_poll(dcb->poll, dcb->active); + dcb->active = 0; + spin_unlock_irqrestore(&dcb->poll->lock, flags); +} + +static unsigned int dma_buf_poll(struct file *file, poll_table *poll) +{ + struct dma_buf *dmabuf; + struct reservation_object *resv; + struct reservation_object_list *fobj; + struct fence *fence_excl; + unsigned long events; + unsigned shared_count, seq; + + dmabuf = file->private_data; + if (!dmabuf || !dmabuf->resv) + return POLLERR; + + resv = dmabuf->resv; + + poll_wait(file, &dmabuf->poll, poll); + + events = poll_requested_events(poll) & (POLLIN | POLLOUT); + if (!events) + return 0; + +retry: + seq = read_seqcount_begin(&resv->seq); + rcu_read_lock(); + + fobj = rcu_dereference(resv->fence); + if (fobj) + shared_count = fobj->shared_count; + else + shared_count = 0; + fence_excl = rcu_dereference(resv->fence_excl); + if (read_seqcount_retry(&resv->seq, seq)) { + rcu_read_unlock(); + goto retry; + } + + if (fence_excl && (!(events & POLLOUT) || shared_count == 0)) { + struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; + unsigned long pevents = POLLIN; + + if (shared_count == 0) + pevents |= POLLOUT; + + spin_lock_irq(&dmabuf->poll.lock); + if (dcb->active) { + dcb->active |= pevents; + events &= ~pevents; + } else + dcb->active = pevents; + spin_unlock_irq(&dmabuf->poll.lock); + + if (events & pevents) { + if (!fence_get_rcu(fence_excl)) { + /* force a recheck */ + events &= ~pevents; + dma_buf_poll_cb(NULL, &dcb->cb); + } else if (!fence_add_callback(fence_excl, &dcb->cb, + dma_buf_poll_cb)) { + events &= ~pevents; + fence_put(fence_excl); + } else { + /* + * No callback queued, wake up any additional + * waiters. + */ + fence_put(fence_excl); + dma_buf_poll_cb(NULL, &dcb->cb); + } + } + } + + if ((events & POLLOUT) && shared_count > 0) { + struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared; + int i; + + /* Only queue a new callback if no event has fired yet */ + spin_lock_irq(&dmabuf->poll.lock); + if (dcb->active) + events &= ~POLLOUT; + else + dcb->active = POLLOUT; + spin_unlock_irq(&dmabuf->poll.lock); + + if (!(events & POLLOUT)) + goto out; + + for (i = 0; i < shared_count; ++i) { + struct fence *fence = rcu_dereference(fobj->shared[i]); + + if (!fence_get_rcu(fence)) { + /* + * fence refcount dropped to zero, this means + * that fobj has been freed + * + * call dma_buf_poll_cb and force a recheck! + */ + events &= ~POLLOUT; + dma_buf_poll_cb(NULL, &dcb->cb); + break; + } + if (!fence_add_callback(fence, &dcb->cb, + dma_buf_poll_cb)) { + fence_put(fence); + events &= ~POLLOUT; + break; + } + fence_put(fence); + } + + /* No callback queued, wake up any additional waiters. */ + if (i == shared_count) + dma_buf_poll_cb(NULL, &dcb->cb); + } + +out: + rcu_read_unlock(); + return events; +} + +static const struct file_operations dma_buf_fops = { + .release = dma_buf_release, + .mmap = dma_buf_mmap_internal, + .llseek = dma_buf_llseek, + .poll = dma_buf_poll, +}; + +/* + * is_dma_buf_file - Check if struct file* is associated with dma_buf + */ +static inline int is_dma_buf_file(struct file *file) +{ + return file->f_op == &dma_buf_fops; +} + +/** + * dma_buf_export - Creates a new dma_buf, and associates an anon file + * with this buffer, so it can be exported. + * Also connect the allocator specific data and ops to the buffer. + * Additionally, provide a name string for exporter; useful in debugging. + * + * @exp_info: [in] holds all the export related information provided + * by the exporter. see struct dma_buf_export_info + * for further details. + * + * Returns, on success, a newly created dma_buf object, which wraps the + * supplied private data and operations for dma_buf_ops. On either missing + * ops, or error in allocating struct dma_buf, will return negative error. + * + */ +struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) +{ + struct dma_buf *dmabuf; + struct reservation_object *resv = exp_info->resv; + struct file *file; + size_t alloc_size = sizeof(struct dma_buf); + if (!exp_info->resv) + alloc_size += sizeof(struct reservation_object); + else + /* prevent &dma_buf[1] == dma_buf->resv */ + alloc_size += 1; + + if (WARN_ON(!exp_info->priv + || !exp_info->ops + || !exp_info->ops->map_dma_buf + || !exp_info->ops->unmap_dma_buf + || !exp_info->ops->release + || !exp_info->ops->kmap_atomic + || !exp_info->ops->kmap + || !exp_info->ops->mmap)) { + return ERR_PTR(-EINVAL); + } + + dmabuf = kzalloc(alloc_size, GFP_KERNEL); + if (dmabuf == NULL) + return ERR_PTR(-ENOMEM); + + dmabuf->priv = exp_info->priv; + dmabuf->ops = exp_info->ops; + dmabuf->size = exp_info->size; + dmabuf->exp_name = exp_info->exp_name; + init_waitqueue_head(&dmabuf->poll); + dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; + dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; + + if (!resv) { + resv = (struct reservation_object *)&dmabuf[1]; + reservation_object_init(resv); + } + dmabuf->resv = resv; + + file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, + exp_info->flags); + if (IS_ERR(file)) { + kfree(dmabuf); + return ERR_CAST(file); + } + + file->f_mode |= FMODE_LSEEK; + dmabuf->file = file; + + mutex_init(&dmabuf->lock); + INIT_LIST_HEAD(&dmabuf->attachments); + + mutex_lock(&db_list.lock); + list_add(&dmabuf->list_node, &db_list.head); + mutex_unlock(&db_list.lock); + + return dmabuf; +} +EXPORT_SYMBOL_GPL(dma_buf_export); + +/** + * dma_buf_fd - returns a file descriptor for the given dma_buf + * @dmabuf: [in] pointer to dma_buf for which fd is required. + * @flags: [in] flags to give to fd + * + * On success, returns an associated 'fd'. Else, returns error. + */ +int dma_buf_fd(struct dma_buf *dmabuf, int flags) +{ + int fd; + + if (!dmabuf || !dmabuf->file) + return -EINVAL; + + fd = get_unused_fd_flags(flags); + if (fd < 0) + return fd; + + fd_install(fd, dmabuf->file); + + return fd; +} +EXPORT_SYMBOL_GPL(dma_buf_fd); + +/** + * dma_buf_get - returns the dma_buf structure related to an fd + * @fd: [in] fd associated with the dma_buf to be returned + * + * On success, returns the dma_buf structure associated with an fd; uses + * file's refcounting done by fget to increase refcount. returns ERR_PTR + * otherwise. + */ +struct dma_buf *dma_buf_get(int fd) +{ + struct file *file; + + file = fget(fd); + + if (!file) + return ERR_PTR(-EBADF); + + if (!is_dma_buf_file(file)) { + fput(file); + return ERR_PTR(-EINVAL); + } + + return file->private_data; +} +EXPORT_SYMBOL_GPL(dma_buf_get); + +/** + * dma_buf_put - decreases refcount of the buffer + * @dmabuf: [in] buffer to reduce refcount of + * + * Uses file's refcounting done implicitly by fput() + */ +void dma_buf_put(struct dma_buf *dmabuf) +{ + if (WARN_ON(!dmabuf || !dmabuf->file)) + return; + + fput(dmabuf->file); +} +EXPORT_SYMBOL_GPL(dma_buf_put); + +/** + * dma_buf_attach - Add the device to dma_buf's attachments list; optionally, + * calls attach() of dma_buf_ops to allow device-specific attach functionality + * @dmabuf: [in] buffer to attach device to. + * @dev: [in] device to be attached. + * + * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on + * error. + */ +struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, + struct device *dev) +{ + struct dma_buf_attachment *attach; + int ret; + + if (WARN_ON(!dmabuf || !dev)) + return ERR_PTR(-EINVAL); + + attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL); + if (attach == NULL) + return ERR_PTR(-ENOMEM); + + attach->dev = dev; + attach->dmabuf = dmabuf; + + mutex_lock(&dmabuf->lock); + + if (dmabuf->ops->attach) { + ret = dmabuf->ops->attach(dmabuf, dev, attach); + if (ret) + goto err_attach; + } + list_add(&attach->node, &dmabuf->attachments); + + mutex_unlock(&dmabuf->lock); + return attach; + +err_attach: + kfree(attach); + mutex_unlock(&dmabuf->lock); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(dma_buf_attach); + +/** + * dma_buf_detach - Remove the given attachment from dmabuf's attachments list; + * optionally calls detach() of dma_buf_ops for device-specific detach + * @dmabuf: [in] buffer to detach from. + * @attach: [in] attachment to be detached; is free'd after this call. + * + */ +void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) +{ + if (WARN_ON(!dmabuf || !attach)) + return; + + mutex_lock(&dmabuf->lock); + list_del(&attach->node); + if (dmabuf->ops->detach) + dmabuf->ops->detach(dmabuf, attach); + + mutex_unlock(&dmabuf->lock); + kfree(attach); +} +EXPORT_SYMBOL_GPL(dma_buf_detach); + +/** + * dma_buf_map_attachment - Returns the scatterlist table of the attachment; + * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the + * dma_buf_ops. + * @attach: [in] attachment whose scatterlist is to be returned + * @direction: [in] direction of DMA transfer + * + * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR + * on error. + */ +struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, + enum dma_data_direction direction) +{ + struct sg_table *sg_table = ERR_PTR(-EINVAL); + + might_sleep(); + + if (WARN_ON(!attach || !attach->dmabuf)) + return ERR_PTR(-EINVAL); + + sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); + if (!sg_table) + sg_table = ERR_PTR(-ENOMEM); + + return sg_table; +} +EXPORT_SYMBOL_GPL(dma_buf_map_attachment); + +/** + * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might + * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of + * dma_buf_ops. + * @attach: [in] attachment to unmap buffer from + * @sg_table: [in] scatterlist info of the buffer to unmap + * @direction: [in] direction of DMA transfer + * + */ +void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, + struct sg_table *sg_table, + enum dma_data_direction direction) +{ + might_sleep(); + + if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) + return; + + attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, + direction); +} +EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); + + +/** + * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the + * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific + * preparations. Coherency is only guaranteed in the specified range for the + * specified access direction. + * @dmabuf: [in] buffer to prepare cpu access for. + * @start: [in] start of range for cpu access. + * @len: [in] length of range for cpu access. + * @direction: [in] length of range for cpu access. + * + * Can return negative error values, returns 0 on success. + */ +int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len, + enum dma_data_direction direction) +{ + int ret = 0; + + if (WARN_ON(!dmabuf)) + return -EINVAL; + + if (dmabuf->ops->begin_cpu_access) + ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction); + + return ret; +} +EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); + +/** + * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the + * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific + * actions. Coherency is only guaranteed in the specified range for the + * specified access direction. + * @dmabuf: [in] buffer to complete cpu access for. + * @start: [in] start of range for cpu access. + * @len: [in] length of range for cpu access. + * @direction: [in] length of range for cpu access. + * + * This call must always succeed. + */ +void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len, + enum dma_data_direction direction) +{ + WARN_ON(!dmabuf); + + if (dmabuf->ops->end_cpu_access) + dmabuf->ops->end_cpu_access(dmabuf, start, len, direction); +} +EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); + +/** + * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address + * space. The same restrictions as for kmap_atomic and friends apply. + * @dmabuf: [in] buffer to map page from. + * @page_num: [in] page in PAGE_SIZE units to map. + * + * This call must always succeed, any necessary preparations that might fail + * need to be done in begin_cpu_access. + */ +void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num) +{ + WARN_ON(!dmabuf); + + return dmabuf->ops->kmap_atomic(dmabuf, page_num); +} +EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic); + +/** + * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic. + * @dmabuf: [in] buffer to unmap page from. + * @page_num: [in] page in PAGE_SIZE units to unmap. + * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic. + * + * This call must always succeed. + */ +void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num, + void *vaddr) +{ + WARN_ON(!dmabuf); + + if (dmabuf->ops->kunmap_atomic) + dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr); +} +EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic); + +/** + * dma_buf_kmap - Map a page of the buffer object into kernel address space. The + * same restrictions as for kmap and friends apply. + * @dmabuf: [in] buffer to map page from. + * @page_num: [in] page in PAGE_SIZE units to map. + * + * This call must always succeed, any necessary preparations that might fail + * need to be done in begin_cpu_access. + */ +void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num) +{ + WARN_ON(!dmabuf); + + return dmabuf->ops->kmap(dmabuf, page_num); +} +EXPORT_SYMBOL_GPL(dma_buf_kmap); + +/** + * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap. + * @dmabuf: [in] buffer to unmap page from. + * @page_num: [in] page in PAGE_SIZE units to unmap. + * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap. + * + * This call must always succeed. + */ +void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, + void *vaddr) +{ + WARN_ON(!dmabuf); + + if (dmabuf->ops->kunmap) + dmabuf->ops->kunmap(dmabuf, page_num, vaddr); +} +EXPORT_SYMBOL_GPL(dma_buf_kunmap); + + +/** + * dma_buf_mmap - Setup up a userspace mmap with the given vma + * @dmabuf: [in] buffer that should back the vma + * @vma: [in] vma for the mmap + * @pgoff: [in] offset in pages where this mmap should start within the + * dma-buf buffer. + * + * This function adjusts the passed in vma so that it points at the file of the + * dma_buf operation. It also adjusts the starting pgoff and does bounds + * checking on the size of the vma. Then it calls the exporters mmap function to + * set up the mapping. + * + * Can return negative error values, returns 0 on success. + */ +int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, + unsigned long pgoff) +{ + struct file *oldfile; + int ret; + + if (WARN_ON(!dmabuf || !vma)) + return -EINVAL; + + /* check for offset overflow */ + if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff) + return -EOVERFLOW; + + /* check for overflowing the buffer's size */ + if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) > + dmabuf->size >> PAGE_SHIFT) + return -EINVAL; + + /* readjust the vma */ + get_file(dmabuf->file); + oldfile = vma->vm_file; + vma->vm_file = dmabuf->file; + vma->vm_pgoff = pgoff; + + ret = dmabuf->ops->mmap(dmabuf, vma); + if (ret) { + /* restore old parameters on failure */ + vma->vm_file = oldfile; + fput(dmabuf->file); + } else { + if (oldfile) + fput(oldfile); + } + return ret; + +} +EXPORT_SYMBOL_GPL(dma_buf_mmap); + +/** + * dma_buf_vmap - Create virtual mapping for the buffer object into kernel + * address space. Same restrictions as for vmap and friends apply. + * @dmabuf: [in] buffer to vmap + * + * This call may fail due to lack of virtual mapping address space. + * These calls are optional in drivers. The intended use for them + * is for mapping objects linear in kernel space for high use objects. + * Please attempt to use kmap/kunmap before thinking about these interfaces. + * + * Returns NULL on error. + */ +void *dma_buf_vmap(struct dma_buf *dmabuf) +{ + void *ptr; + + if (WARN_ON(!dmabuf)) + return NULL; + + if (!dmabuf->ops->vmap) + return NULL; + + mutex_lock(&dmabuf->lock); + if (dmabuf->vmapping_counter) { + dmabuf->vmapping_counter++; + BUG_ON(!dmabuf->vmap_ptr); + ptr = dmabuf->vmap_ptr; + goto out_unlock; + } + + BUG_ON(dmabuf->vmap_ptr); + + ptr = dmabuf->ops->vmap(dmabuf); + if (WARN_ON_ONCE(IS_ERR(ptr))) + ptr = NULL; + if (!ptr) + goto out_unlock; + + dmabuf->vmap_ptr = ptr; + dmabuf->vmapping_counter = 1; + +out_unlock: + mutex_unlock(&dmabuf->lock); + return ptr; +} +EXPORT_SYMBOL_GPL(dma_buf_vmap); + +/** + * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. + * @dmabuf: [in] buffer to vunmap + * @vaddr: [in] vmap to vunmap + */ +void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) +{ + if (WARN_ON(!dmabuf)) + return; + + BUG_ON(!dmabuf->vmap_ptr); + BUG_ON(dmabuf->vmapping_counter == 0); + BUG_ON(dmabuf->vmap_ptr != vaddr); + + mutex_lock(&dmabuf->lock); + if (--dmabuf->vmapping_counter == 0) { + if (dmabuf->ops->vunmap) + dmabuf->ops->vunmap(dmabuf, vaddr); + dmabuf->vmap_ptr = NULL; + } + mutex_unlock(&dmabuf->lock); +} +EXPORT_SYMBOL_GPL(dma_buf_vunmap); + +#ifdef CONFIG_DEBUG_FS +static int dma_buf_describe(struct seq_file *s) +{ + int ret; + struct dma_buf *buf_obj; + struct dma_buf_attachment *attach_obj; + int count = 0, attach_count; + size_t size = 0; + + ret = mutex_lock_interruptible(&db_list.lock); + + if (ret) + return ret; + + seq_puts(s, "\nDma-buf Objects:\n"); + seq_puts(s, "size\tflags\tmode\tcount\texp_name\n"); + + list_for_each_entry(buf_obj, &db_list.head, list_node) { + ret = mutex_lock_interruptible(&buf_obj->lock); + + if (ret) { + seq_puts(s, + "\tERROR locking buffer object: skipping\n"); + continue; + } + + seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n", + buf_obj->size, + buf_obj->file->f_flags, buf_obj->file->f_mode, + file_count(buf_obj->file), + buf_obj->exp_name); + + seq_puts(s, "\tAttached Devices:\n"); + attach_count = 0; + + list_for_each_entry(attach_obj, &buf_obj->attachments, node) { + seq_puts(s, "\t"); + + seq_printf(s, "%s\n", dev_name(attach_obj->dev)); + attach_count++; + } + + seq_printf(s, "Total %d devices attached\n\n", + attach_count); + + count++; + size += buf_obj->size; + mutex_unlock(&buf_obj->lock); + } + + seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); + + mutex_unlock(&db_list.lock); + return 0; +} + +static int dma_buf_show(struct seq_file *s, void *unused) +{ + void (*func)(struct seq_file *) = s->private; + func(s); + return 0; +} + +static int dma_buf_debug_open(struct inode *inode, struct file *file) +{ + return single_open(file, dma_buf_show, inode->i_private); +} + +static const struct file_operations dma_buf_debug_fops = { + .open = dma_buf_debug_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static struct dentry *dma_buf_debugfs_dir; + +static int dma_buf_init_debugfs(void) +{ + int err = 0; + dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL); + if (IS_ERR(dma_buf_debugfs_dir)) { + err = PTR_ERR(dma_buf_debugfs_dir); + dma_buf_debugfs_dir = NULL; + return err; + } + + err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe); + + if (err) + pr_debug("dma_buf: debugfs: failed to create node bufinfo\n"); + + return err; +} + +static void dma_buf_uninit_debugfs(void) +{ + if (dma_buf_debugfs_dir) + debugfs_remove_recursive(dma_buf_debugfs_dir); +} + +int dma_buf_debugfs_create_file(const char *name, + int (*write)(struct seq_file *)) +{ + struct dentry *d; + + d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir, + write, &dma_buf_debug_fops); + + return PTR_ERR_OR_ZERO(d); +} +#else +static inline int dma_buf_init_debugfs(void) +{ + return 0; +} +static inline void dma_buf_uninit_debugfs(void) +{ +} +#endif + +static int __init dma_buf_init(void) +{ + mutex_init(&db_list.lock); + INIT_LIST_HEAD(&db_list.head); + dma_buf_init_debugfs(); + return 0; +} +subsys_initcall(dma_buf_init); + +static void __exit dma_buf_deinit(void) +{ + dma_buf_uninit_debugfs(); +} +__exitcall(dma_buf_deinit); diff --git a/drivers/dma-buf/fence.c b/drivers/dma-buf/fence.c new file mode 100644 index 000000000..50ef8bd87 --- /dev/null +++ b/drivers/dma-buf/fence.c @@ -0,0 +1,434 @@ +/* + * Fence mechanism for dma-buf and to allow for asynchronous dma access + * + * Copyright (C) 2012 Canonical Ltd + * Copyright (C) 2012 Texas Instruments + * + * Authors: + * Rob Clark <robdclark@gmail.com> + * Maarten Lankhorst <maarten.lankhorst@canonical.com> + * + * 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. + */ + +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/atomic.h> +#include <linux/fence.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/fence.h> + +EXPORT_TRACEPOINT_SYMBOL(fence_annotate_wait_on); +EXPORT_TRACEPOINT_SYMBOL(fence_emit); + +/* + * fence context counter: each execution context should have its own + * fence context, this allows checking if fences belong to the same + * context or not. One device can have multiple separate contexts, + * and they're used if some engine can run independently of another. + */ +static atomic_t fence_context_counter = ATOMIC_INIT(0); + +/** + * fence_context_alloc - allocate an array of fence contexts + * @num: [in] amount of contexts to allocate + * + * This function will return the first index of the number of fences allocated. + * The fence context is used for setting fence->context to a unique number. + */ +unsigned fence_context_alloc(unsigned num) +{ + BUG_ON(!num); + return atomic_add_return(num, &fence_context_counter) - num; +} +EXPORT_SYMBOL(fence_context_alloc); + +/** + * fence_signal_locked - signal completion of a fence + * @fence: the fence to signal + * + * Signal completion for software callbacks on a fence, this will unblock + * fence_wait() calls and run all the callbacks added with + * fence_add_callback(). Can be called multiple times, but since a fence + * can only go from unsignaled to signaled state, it will only be effective + * the first time. + * + * Unlike fence_signal, this function must be called with fence->lock held. + */ +int fence_signal_locked(struct fence *fence) +{ + struct fence_cb *cur, *tmp; + int ret = 0; + + if (WARN_ON(!fence)) + return -EINVAL; + + if (!ktime_to_ns(fence->timestamp)) { + fence->timestamp = ktime_get(); + smp_mb__before_atomic(); + } + + if (test_and_set_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { + ret = -EINVAL; + + /* + * we might have raced with the unlocked fence_signal, + * still run through all callbacks + */ + } else + trace_fence_signaled(fence); + + list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) { + list_del_init(&cur->node); + cur->func(fence, cur); + } + return ret; +} +EXPORT_SYMBOL(fence_signal_locked); + +/** + * fence_signal - signal completion of a fence + * @fence: the fence to signal + * + * Signal completion for software callbacks on a fence, this will unblock + * fence_wait() calls and run all the callbacks added with + * fence_add_callback(). Can be called multiple times, but since a fence + * can only go from unsignaled to signaled state, it will only be effective + * the first time. + */ +int fence_signal(struct fence *fence) +{ + unsigned long flags; + + if (!fence) + return -EINVAL; + + if (!ktime_to_ns(fence->timestamp)) { + fence->timestamp = ktime_get(); + smp_mb__before_atomic(); + } + + if (test_and_set_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) + return -EINVAL; + + trace_fence_signaled(fence); + + if (test_bit(FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) { + struct fence_cb *cur, *tmp; + + spin_lock_irqsave(fence->lock, flags); + list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) { + list_del_init(&cur->node); + cur->func(fence, cur); + } + spin_unlock_irqrestore(fence->lock, flags); + } + return 0; +} +EXPORT_SYMBOL(fence_signal); + +/** + * fence_wait_timeout - sleep until the fence gets signaled + * or until timeout elapses + * @fence: [in] the fence to wait on + * @intr: [in] if true, do an interruptible wait + * @timeout: [in] timeout value in jiffies, or MAX_SCHEDULE_TIMEOUT + * + * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or the + * remaining timeout in jiffies on success. Other error values may be + * returned on custom implementations. + * + * Performs a synchronous wait on this fence. It is assumed the caller + * directly or indirectly (buf-mgr between reservation and committing) + * holds a reference to the fence, otherwise the fence might be + * freed before return, resulting in undefined behavior. + */ +signed long +fence_wait_timeout(struct fence *fence, bool intr, signed long timeout) +{ + signed long ret; + + if (WARN_ON(timeout < 0)) + return -EINVAL; + + if (timeout == 0) + return fence_is_signaled(fence); + + trace_fence_wait_start(fence); + ret = fence->ops->wait(fence, intr, timeout); + trace_fence_wait_end(fence); + return ret; +} +EXPORT_SYMBOL(fence_wait_timeout); + +void fence_release(struct kref *kref) +{ + struct fence *fence = + container_of(kref, struct fence, refcount); + + trace_fence_destroy(fence); + + BUG_ON(!list_empty(&fence->cb_list)); + + if (fence->ops->release) + fence->ops->release(fence); + else + fence_free(fence); +} +EXPORT_SYMBOL(fence_release); + +void fence_free(struct fence *fence) +{ + kfree_rcu(fence, rcu); +} +EXPORT_SYMBOL(fence_free); + +/** + * fence_enable_sw_signaling - enable signaling on fence + * @fence: [in] the fence to enable + * + * this will request for sw signaling to be enabled, to make the fence + * complete as soon as possible + */ +void fence_enable_sw_signaling(struct fence *fence) +{ + unsigned long flags; + + if (!test_and_set_bit(FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags) && + !test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { + trace_fence_enable_signal(fence); + + spin_lock_irqsave(fence->lock, flags); + + if (!fence->ops->enable_signaling(fence)) + fence_signal_locked(fence); + + spin_unlock_irqrestore(fence->lock, flags); + } +} +EXPORT_SYMBOL(fence_enable_sw_signaling); + +/** + * fence_add_callback - add a callback to be called when the fence + * is signaled + * @fence: [in] the fence to wait on + * @cb: [in] the callback to register + * @func: [in] the function to call + * + * cb will be initialized by fence_add_callback, no initialization + * by the caller is required. Any number of callbacks can be registered + * to a fence, but a callback can only be registered to one fence at a time. + * + * Note that the callback can be called from an atomic context. If + * fence is already signaled, this function will return -ENOENT (and + * *not* call the callback) + * + * Add a software callback to the fence. Same restrictions apply to + * refcount as it does to fence_wait, however the caller doesn't need to + * keep a refcount to fence afterwards: when software access is enabled, + * the creator of the fence is required to keep the fence alive until + * after it signals with fence_signal. The callback itself can be called + * from irq context. + * + */ +int fence_add_callback(struct fence *fence, struct fence_cb *cb, + fence_func_t func) +{ + unsigned long flags; + int ret = 0; + bool was_set; + + if (WARN_ON(!fence || !func)) + return -EINVAL; + + if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { + INIT_LIST_HEAD(&cb->node); + return -ENOENT; + } + + spin_lock_irqsave(fence->lock, flags); + + was_set = test_and_set_bit(FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags); + + if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) + ret = -ENOENT; + else if (!was_set) { + trace_fence_enable_signal(fence); + + if (!fence->ops->enable_signaling(fence)) { + fence_signal_locked(fence); + ret = -ENOENT; + } + } + + if (!ret) { + cb->func = func; + list_add_tail(&cb->node, &fence->cb_list); + } else + INIT_LIST_HEAD(&cb->node); + spin_unlock_irqrestore(fence->lock, flags); + + return ret; +} +EXPORT_SYMBOL(fence_add_callback); + +/** + * fence_remove_callback - remove a callback from the signaling list + * @fence: [in] the fence to wait on + * @cb: [in] the callback to remove + * + * Remove a previously queued callback from the fence. This function returns + * true if the callback is successfully removed, or false if the fence has + * already been signaled. + * + * *WARNING*: + * Cancelling a callback should only be done if you really know what you're + * doing, since deadlocks and race conditions could occur all too easily. For + * this reason, it should only ever be done on hardware lockup recovery, + * with a reference held to the fence. + */ +bool +fence_remove_callback(struct fence *fence, struct fence_cb *cb) +{ + unsigned long flags; + bool ret; + + spin_lock_irqsave(fence->lock, flags); + + ret = !list_empty(&cb->node); + if (ret) + list_del_init(&cb->node); + + spin_unlock_irqrestore(fence->lock, flags); + + return ret; +} +EXPORT_SYMBOL(fence_remove_callback); + +struct default_wait_cb { + struct fence_cb base; + struct task_struct *task; +}; + +static void +fence_default_wait_cb(struct fence *fence, struct fence_cb *cb) +{ + struct default_wait_cb *wait = + container_of(cb, struct default_wait_cb, base); + + wake_up_state(wait->task, TASK_NORMAL); +} + +/** + * fence_default_wait - default sleep until the fence gets signaled + * or until timeout elapses + * @fence: [in] the fence to wait on + * @intr: [in] if true, do an interruptible wait + * @timeout: [in] timeout value in jiffies, or MAX_SCHEDULE_TIMEOUT + * + * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or the + * remaining timeout in jiffies on success. + */ +signed long +fence_default_wait(struct fence *fence, bool intr, signed long timeout) +{ + struct default_wait_cb cb; + unsigned long flags; + signed long ret = timeout; + bool was_set; + + if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) + return timeout; + + spin_lock_irqsave(fence->lock, flags); + + if (intr && signal_pending(current)) { + ret = -ERESTARTSYS; + goto out; + } + + was_set = test_and_set_bit(FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags); + + if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags)) + goto out; + + if (!was_set) { + trace_fence_enable_signal(fence); + + if (!fence->ops->enable_signaling(fence)) { + fence_signal_locked(fence); + goto out; + } + } + + cb.base.func = fence_default_wait_cb; + cb.task = current; + list_add(&cb.base.node, &fence->cb_list); + + while (!test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags) && ret > 0) { + if (intr) + __set_current_state(TASK_INTERRUPTIBLE); + else + __set_current_state(TASK_UNINTERRUPTIBLE); + spin_unlock_irqrestore(fence->lock, flags); + + ret = schedule_timeout(ret); + + spin_lock_irqsave(fence->lock, flags); + if (ret > 0 && intr && signal_pending(current)) + ret = -ERESTARTSYS; + } + + if (!list_empty(&cb.base.node)) + list_del(&cb.base.node); + __set_current_state(TASK_RUNNING); + +out: + spin_unlock_irqrestore(fence->lock, flags); + return ret; +} +EXPORT_SYMBOL(fence_default_wait); + +/** + * fence_init - Initialize a custom fence. + * @fence: [in] the fence to initialize + * @ops: [in] the fence_ops for operations on this fence + * @lock: [in] the irqsafe spinlock to use for locking this fence + * @context: [in] the execution context this fence is run on + * @seqno: [in] a linear increasing sequence number for this context + * + * Initializes an allocated fence, the caller doesn't have to keep its + * refcount after committing with this fence, but it will need to hold a + * refcount again if fence_ops.enable_signaling gets called. This can + * be used for other implementing other types of fence. + * + * context and seqno are used for easy comparison between fences, allowing + * to check which fence is later by simply using fence_later. + */ +void +fence_init(struct fence *fence, const struct fence_ops *ops, + spinlock_t *lock, unsigned context, unsigned seqno) +{ + BUG_ON(!lock); + BUG_ON(!ops || !ops->wait || !ops->enable_signaling || + !ops->get_driver_name || !ops->get_timeline_name); + + kref_init(&fence->refcount); + fence->ops = ops; + INIT_LIST_HEAD(&fence->cb_list); + fence->lock = lock; + fence->context = context; + fence->seqno = seqno; + fence->flags = 0UL; + + trace_fence_init(fence); +} +EXPORT_SYMBOL(fence_init); diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c new file mode 100644 index 000000000..39920d77f --- /dev/null +++ b/drivers/dma-buf/reservation.c @@ -0,0 +1,478 @@ +/* + * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst) + * + * Based on bo.c which bears the following copyright notice, + * but is dual licensed: + * + * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA + * All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sub license, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice (including the + * next paragraph) shall be included in all copies or substantial portions + * of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE + * USE OR OTHER DEALINGS IN THE SOFTWARE. + * + **************************************************************************/ +/* + * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> + */ + +#include <linux/reservation.h> +#include <linux/export.h> + +DEFINE_WW_CLASS(reservation_ww_class); +EXPORT_SYMBOL(reservation_ww_class); + +struct lock_class_key reservation_seqcount_class; +EXPORT_SYMBOL(reservation_seqcount_class); + +const char reservation_seqcount_string[] = "reservation_seqcount"; +EXPORT_SYMBOL(reservation_seqcount_string); +/* + * Reserve space to add a shared fence to a reservation_object, + * must be called with obj->lock held. + */ +int reservation_object_reserve_shared(struct reservation_object *obj) +{ + struct reservation_object_list *fobj, *old; + u32 max; + + old = reservation_object_get_list(obj); + + if (old && old->shared_max) { + if (old->shared_count < old->shared_max) { + /* perform an in-place update */ + kfree(obj->staged); + obj->staged = NULL; + return 0; + } else + max = old->shared_max * 2; + } else + max = 4; + + /* + * resize obj->staged or allocate if it doesn't exist, + * noop if already correct size + */ + fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]), + GFP_KERNEL); + if (!fobj) + return -ENOMEM; + + obj->staged = fobj; + fobj->shared_max = max; + return 0; +} +EXPORT_SYMBOL(reservation_object_reserve_shared); + +static void +reservation_object_add_shared_inplace(struct reservation_object *obj, + struct reservation_object_list *fobj, + struct fence *fence) +{ + u32 i; + + fence_get(fence); + + preempt_disable(); + write_seqcount_begin(&obj->seq); + + for (i = 0; i < fobj->shared_count; ++i) { + struct fence *old_fence; + + old_fence = rcu_dereference_protected(fobj->shared[i], + reservation_object_held(obj)); + + if (old_fence->context == fence->context) { + /* memory barrier is added by write_seqcount_begin */ + RCU_INIT_POINTER(fobj->shared[i], fence); + write_seqcount_end(&obj->seq); + preempt_enable(); + + fence_put(old_fence); + return; + } + } + + /* + * memory barrier is added by write_seqcount_begin, + * fobj->shared_count is protected by this lock too + */ + RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); + fobj->shared_count++; + + write_seqcount_end(&obj->seq); + preempt_enable(); +} + +static void +reservation_object_add_shared_replace(struct reservation_object *obj, + struct reservation_object_list *old, + struct reservation_object_list *fobj, + struct fence *fence) +{ + unsigned i; + struct fence *old_fence = NULL; + + fence_get(fence); + + if (!old) { + RCU_INIT_POINTER(fobj->shared[0], fence); + fobj->shared_count = 1; + goto done; + } + + /* + * no need to bump fence refcounts, rcu_read access + * requires the use of kref_get_unless_zero, and the + * references from the old struct are carried over to + * the new. + */ + fobj->shared_count = old->shared_count; + + for (i = 0; i < old->shared_count; ++i) { + struct fence *check; + + check = rcu_dereference_protected(old->shared[i], + reservation_object_held(obj)); + + if (!old_fence && check->context == fence->context) { + old_fence = check; + RCU_INIT_POINTER(fobj->shared[i], fence); + } else + RCU_INIT_POINTER(fobj->shared[i], check); + } + if (!old_fence) { + RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence); + fobj->shared_count++; + } + +done: + preempt_disable(); + write_seqcount_begin(&obj->seq); + /* + * RCU_INIT_POINTER can be used here, + * seqcount provides the necessary barriers + */ + RCU_INIT_POINTER(obj->fence, fobj); + write_seqcount_end(&obj->seq); + preempt_enable(); + + if (old) + kfree_rcu(old, rcu); + + if (old_fence) + fence_put(old_fence); +} + +/* + * Add a fence to a shared slot, obj->lock must be held, and + * reservation_object_reserve_shared_fence has been called. + */ +void reservation_object_add_shared_fence(struct reservation_object *obj, + struct fence *fence) +{ + struct reservation_object_list *old, *fobj = obj->staged; + + old = reservation_object_get_list(obj); + obj->staged = NULL; + + if (!fobj) { + BUG_ON(old->shared_count >= old->shared_max); + reservation_object_add_shared_inplace(obj, old, fence); + } else + reservation_object_add_shared_replace(obj, old, fobj, fence); +} +EXPORT_SYMBOL(reservation_object_add_shared_fence); + +void reservation_object_add_excl_fence(struct reservation_object *obj, + struct fence *fence) +{ + struct fence *old_fence = reservation_object_get_excl(obj); + struct reservation_object_list *old; + u32 i = 0; + + old = reservation_object_get_list(obj); + if (old) + i = old->shared_count; + + if (fence) + fence_get(fence); + + preempt_disable(); + write_seqcount_begin(&obj->seq); + /* write_seqcount_begin provides the necessary memory barrier */ + RCU_INIT_POINTER(obj->fence_excl, fence); + if (old) + old->shared_count = 0; + write_seqcount_end(&obj->seq); + preempt_enable(); + + /* inplace update, no shared fences */ + while (i--) + fence_put(rcu_dereference_protected(old->shared[i], + reservation_object_held(obj))); + + if (old_fence) + fence_put(old_fence); +} +EXPORT_SYMBOL(reservation_object_add_excl_fence); + +int reservation_object_get_fences_rcu(struct reservation_object *obj, + struct fence **pfence_excl, + unsigned *pshared_count, + struct fence ***pshared) +{ + unsigned shared_count = 0; + unsigned retry = 1; + struct fence **shared = NULL, *fence_excl = NULL; + int ret = 0; + + while (retry) { + struct reservation_object_list *fobj; + unsigned seq; + + seq = read_seqcount_begin(&obj->seq); + + rcu_read_lock(); + + fobj = rcu_dereference(obj->fence); + if (fobj) { + struct fence **nshared; + size_t sz = sizeof(*shared) * fobj->shared_max; + + nshared = krealloc(shared, sz, + GFP_NOWAIT | __GFP_NOWARN); + if (!nshared) { + rcu_read_unlock(); + nshared = krealloc(shared, sz, GFP_KERNEL); + if (nshared) { + shared = nshared; + continue; + } + + ret = -ENOMEM; + shared_count = 0; + break; + } + shared = nshared; + memcpy(shared, fobj->shared, sz); + shared_count = fobj->shared_count; + } else + shared_count = 0; + fence_excl = rcu_dereference(obj->fence_excl); + + retry = read_seqcount_retry(&obj->seq, seq); + if (retry) + goto unlock; + + if (!fence_excl || fence_get_rcu(fence_excl)) { + unsigned i; + + for (i = 0; i < shared_count; ++i) { + if (fence_get_rcu(shared[i])) + continue; + + /* uh oh, refcount failed, abort and retry */ + while (i--) + fence_put(shared[i]); + + if (fence_excl) { + fence_put(fence_excl); + fence_excl = NULL; + } + + retry = 1; + break; + } + } else + retry = 1; + +unlock: + rcu_read_unlock(); + } + *pshared_count = shared_count; + if (shared_count) + *pshared = shared; + else { + *pshared = NULL; + kfree(shared); + } + *pfence_excl = fence_excl; + + return ret; +} +EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu); + +long reservation_object_wait_timeout_rcu(struct reservation_object *obj, + bool wait_all, bool intr, + unsigned long timeout) +{ + struct fence *fence; + unsigned seq, shared_count, i = 0; + long ret = timeout; + + if (!timeout) + return reservation_object_test_signaled_rcu(obj, wait_all); + +retry: + fence = NULL; + shared_count = 0; + seq = read_seqcount_begin(&obj->seq); + rcu_read_lock(); + + if (wait_all) { + struct reservation_object_list *fobj = rcu_dereference(obj->fence); + + if (fobj) + shared_count = fobj->shared_count; + + if (read_seqcount_retry(&obj->seq, seq)) + goto unlock_retry; + + for (i = 0; i < shared_count; ++i) { + struct fence *lfence = rcu_dereference(fobj->shared[i]); + + if (test_bit(FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) + continue; + + if (!fence_get_rcu(lfence)) + goto unlock_retry; + + if (fence_is_signaled(lfence)) { + fence_put(lfence); + continue; + } + + fence = lfence; + break; + } + } + + if (!shared_count) { + struct fence *fence_excl = rcu_dereference(obj->fence_excl); + + if (read_seqcount_retry(&obj->seq, seq)) + goto unlock_retry; + + if (fence_excl && + !test_bit(FENCE_FLAG_SIGNALED_BIT, &fence_excl->flags)) { + if (!fence_get_rcu(fence_excl)) + goto unlock_retry; + + if (fence_is_signaled(fence_excl)) + fence_put(fence_excl); + else + fence = fence_excl; + } + } + + rcu_read_unlock(); + if (fence) { + ret = fence_wait_timeout(fence, intr, ret); + fence_put(fence); + if (ret > 0 && wait_all && (i + 1 < shared_count)) + goto retry; + } + return ret; + +unlock_retry: + rcu_read_unlock(); + goto retry; +} +EXPORT_SYMBOL_GPL(reservation_object_wait_timeout_rcu); + + +static inline int +reservation_object_test_signaled_single(struct fence *passed_fence) +{ + struct fence *fence, *lfence = passed_fence; + int ret = 1; + + if (!test_bit(FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) { + fence = fence_get_rcu(lfence); + if (!fence) + return -1; + + ret = !!fence_is_signaled(fence); + fence_put(fence); + } + return ret; +} + +bool reservation_object_test_signaled_rcu(struct reservation_object *obj, + bool test_all) +{ + unsigned seq, shared_count; + int ret = true; + +retry: + shared_count = 0; + seq = read_seqcount_begin(&obj->seq); + rcu_read_lock(); + + if (test_all) { + unsigned i; + + struct reservation_object_list *fobj = rcu_dereference(obj->fence); + + if (fobj) + shared_count = fobj->shared_count; + + if (read_seqcount_retry(&obj->seq, seq)) + goto unlock_retry; + + for (i = 0; i < shared_count; ++i) { + struct fence *fence = rcu_dereference(fobj->shared[i]); + + ret = reservation_object_test_signaled_single(fence); + if (ret < 0) + goto unlock_retry; + else if (!ret) + break; + } + + /* + * There could be a read_seqcount_retry here, but nothing cares + * about whether it's the old or newer fence pointers that are + * signaled. That race could still have happened after checking + * read_seqcount_retry. If you care, use ww_mutex_lock. + */ + } + + if (!shared_count) { + struct fence *fence_excl = rcu_dereference(obj->fence_excl); + + if (read_seqcount_retry(&obj->seq, seq)) + goto unlock_retry; + + if (fence_excl) { + ret = reservation_object_test_signaled_single(fence_excl); + if (ret < 0) + goto unlock_retry; + } + } + + rcu_read_unlock(); + return ret; + +unlock_retry: + rcu_read_unlock(); + goto retry; +} +EXPORT_SYMBOL_GPL(reservation_object_test_signaled_rcu); diff --git a/drivers/dma-buf/seqno-fence.c b/drivers/dma-buf/seqno-fence.c new file mode 100644 index 000000000..7d12a39a4 --- /dev/null +++ b/drivers/dma-buf/seqno-fence.c @@ -0,0 +1,73 @@ +/* + * seqno-fence, using a dma-buf to synchronize fencing + * + * Copyright (C) 2012 Texas Instruments + * Copyright (C) 2012-2014 Canonical Ltd + * Authors: + * Rob Clark <robdclark@gmail.com> + * Maarten Lankhorst <maarten.lankhorst@canonical.com> + * + * 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. + */ + +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/seqno-fence.h> + +static const char *seqno_fence_get_driver_name(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->get_driver_name(fence); +} + +static const char *seqno_fence_get_timeline_name(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->get_timeline_name(fence); +} + +static bool seqno_enable_signaling(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->enable_signaling(fence); +} + +static bool seqno_signaled(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->signaled && seqno_fence->ops->signaled(fence); +} + +static void seqno_release(struct fence *fence) +{ + struct seqno_fence *f = to_seqno_fence(fence); + + dma_buf_put(f->sync_buf); + if (f->ops->release) + f->ops->release(fence); + else + fence_free(&f->base); +} + +static signed long seqno_wait(struct fence *fence, bool intr, signed long timeout) +{ + struct seqno_fence *f = to_seqno_fence(fence); + return f->ops->wait(fence, intr, timeout); +} + +const struct fence_ops seqno_fence_ops = { + .get_driver_name = seqno_fence_get_driver_name, + .get_timeline_name = seqno_fence_get_timeline_name, + .enable_signaling = seqno_enable_signaling, + .signaled = seqno_signaled, + .wait = seqno_wait, + .release = seqno_release, +}; +EXPORT_SYMBOL(seqno_fence_ops); |