[PATCH 2/2] dma-buf/sync_file: rework fence storage in struct file

From: Gustavo Padovan gustavo.padovan@collabora.co.uk

Create sync_file->fence to abstract the type of fence we are using for each sync_file. If only one fence is present we use a normal struct fence but if there is more fences to be added to the sync_file a fence_array is created.

This change cleans up sync_file a bit. We don't need to have sync_file_cb array anymore. Instead, as we always have one fence, only one fence callback is registered per sync_file.

v3: Comments from Chris Wilson and Christian König - struct sync_file lost status member in favor of fence_is_signaled() - drop use of fence_array_teardown() - use sizeof(*fence) to allocate only an array on fence pointers

v2: Comments from Chris Wilson and Christian König - Not using fence_ops anymore - fence_is_array() was created to differentiate fence from fence_array - fence_array_teardown() is now exported and used under fence_is_array() - struct sync_file lost num_fences member

Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Christian König christian.koenig@amd.com Signed-off-by: Gustavo Padovan gustavo.padovan@collabora.co.uk --- drivers/dma-buf/sync_file.c | 163 ++++++++++++++++++++++------------- drivers/staging/android/sync_debug.c | 13 ++- include/linux/sync_file.h | 17 ++-- 3 files changed, 118 insertions(+), 75 deletions(-)

diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c index 9aaa608..7a5aaae 100644 --- a/drivers/dma-buf/sync_file.c +++ b/drivers/dma-buf/sync_file.c @@ -28,11 +28,11 @@

static const struct file_operations sync_file_fops;

-static struct sync_file *sync_file_alloc(int size) +static struct sync_file *sync_file_alloc(void) { struct sync_file *sync_file;

- sync_file = kzalloc(size, GFP_KERNEL); + sync_file = kzalloc(sizeof(*sync_file), GFP_KERNEL); if (!sync_file) return NULL;

@@ -45,6 +45,8 @@ static struct sync_file *sync_file_alloc(int size)

init_waitqueue_head(&sync_file->wq);

+ INIT_LIST_HEAD(&sync_file->cb.node); + return sync_file;

err: @@ -54,14 +56,11 @@ err:

static void fence_check_cb_func(struct fence *f, struct fence_cb *cb) { - struct sync_file_cb *check; struct sync_file *sync_file;

- check = container_of(cb, struct sync_file_cb, cb); - sync_file = check->sync_file; + sync_file = container_of(cb, struct sync_file, cb);

- if (atomic_dec_and_test(&sync_file->status)) - wake_up_all(&sync_file->wq); + wake_up_all(&sync_file->wq); }

/** @@ -76,22 +75,18 @@ struct sync_file *sync_file_create(struct fence *fence) { struct sync_file *sync_file;

- sync_file = sync_file_alloc(offsetof(struct sync_file, cbs[1])); + sync_file = sync_file_alloc(); if (!sync_file) return NULL;

- sync_file->num_fences = 1; - atomic_set(&sync_file->status, 1); + sync_file->fence = fence; + snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), fence->context, fence->seqno);

- sync_file->cbs[0].fence = fence; - sync_file->cbs[0].sync_file = sync_file; - if (fence_add_callback(fence, &sync_file->cbs[0].cb, - fence_check_cb_func)) - atomic_dec(&sync_file->status); + fence_add_callback(fence, &sync_file->cb, fence_check_cb_func);

return sync_file; } @@ -121,14 +116,48 @@ err: return NULL; }

-static void sync_file_add_pt(struct sync_file *sync_file, int *i, - struct fence *fence) +static int sync_file_set_fence(struct sync_file *sync_file, + struct fence **fences, int num_fences) +{ + struct fence_array *array; + + /* + * The reference for the fences in the new sync_file and holded + * in add_fence() during the merge procedure, so for num_fences == 1 + * we already own a new reference to the fence. For num_fence > 1 + * we own the reference of the fence_array creation. + */ + if (num_fences == 1) { + sync_file->fence = fences[0]; + } else { + array = fence_array_create(num_fences, fences, + fence_context_alloc(1), 1, false); + if (!array) + return -ENOMEM; + + sync_file->fence = (struct fence *)array; + } + + return 0; +} + +static struct fence **get_fences(struct sync_file *sync_file, int *num_fences) +{ + if (fence_is_array(sync_file->fence)) { + struct fence_array *array = to_fence_array(sync_file->fence); + *num_fences = array->num_fences; + return array->fences; + } else { + *num_fences = 1; + return &sync_file->fence; + } +} + +static void add_fence(struct fence **fences, int *i, struct fence *fence) { - sync_file->cbs[*i].fence = fence; - sync_file->cbs[*i].sync_file = sync_file; + fences[*i] = fence;

- if (!fence_add_callback(fence, &sync_file->cbs[*i].cb, - fence_check_cb_func)) { + if (!fence_is_signaled(fence)) { fence_get(fence); (*i)++; } @@ -147,16 +176,21 @@ static void sync_file_add_pt(struct sync_file *sync_file, int *i, static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, struct sync_file *b) { - int num_fences = a->num_fences + b->num_fences; struct sync_file *sync_file; - int i, i_a, i_b; - unsigned long size = offsetof(struct sync_file, cbs[num_fences]); + struct fence **fences, **a_fences, **b_fences; + int i, i_a, i_b, num_fences, a_num_fences, b_num_fences;

- sync_file = sync_file_alloc(size); + sync_file = sync_file_alloc(); if (!sync_file) return NULL;

- atomic_set(&sync_file->status, num_fences); + a_fences = get_fences(a, &a_num_fences); + b_fences = get_fences(b, &b_num_fences); + num_fences = a_num_fences + b_num_fences; + + fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL); + if (!fences) + goto err;

/* * Assume sync_file a and b are both ordered and have no @@ -165,55 +199,66 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, * If a sync_file can only be created with sync_file_merge * and sync_file_create, this is a reasonable assumption. */ - for (i = i_a = i_b = 0; i_a < a->num_fences && i_b < b->num_fences; ) { - struct fence *pt_a = a->cbs[i_a].fence; - struct fence *pt_b = b->cbs[i_b].fence; + for (i = i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) { + struct fence *pt_a = a_fences[i_a]; + struct fence *pt_b = b_fences[i_b];

if (pt_a->context < pt_b->context) { - sync_file_add_pt(sync_file, &i, pt_a); + add_fence(fences, &i, pt_a);

i_a++; } else if (pt_a->context > pt_b->context) { - sync_file_add_pt(sync_file, &i, pt_b); + add_fence(fences, &i, pt_b);

i_b++; } else { if (pt_a->seqno - pt_b->seqno <= INT_MAX) - sync_file_add_pt(sync_file, &i, pt_a); + add_fence(fences, &i, pt_a); else - sync_file_add_pt(sync_file, &i, pt_b); + add_fence(fences, &i, pt_b);

i_a++; i_b++; } }

- for (; i_a < a->num_fences; i_a++) - sync_file_add_pt(sync_file, &i, a->cbs[i_a].fence); + for (; i_a < a_num_fences; i_a++) + add_fence(fences, &i, a_fences[i_a]); + + for (; i_b < b_num_fences; i_b++) + add_fence(fences, &i, b_fences[i_b]); + + if (num_fences > i) { + fences = krealloc(fences, i * sizeof(**fences), + GFP_KERNEL); + if (!fences) + goto err; + }

- for (; i_b < b->num_fences; i_b++) - sync_file_add_pt(sync_file, &i, b->cbs[i_b].fence); + if (sync_file_set_fence(sync_file, fences, i) < 0) { + kfree(fences); + goto err; + }

- if (num_fences > i) - atomic_sub(num_fences - i, &sync_file->status); - sync_file->num_fences = i; + fence_add_callback(sync_file->fence, &sync_file->cb, + fence_check_cb_func);

strlcpy(sync_file->name, name, sizeof(sync_file->name)); return sync_file; + +err: + fput(sync_file->file); + return NULL; + }

static void sync_file_free(struct kref *kref) { struct sync_file *sync_file = container_of(kref, struct sync_file, kref); - int i; - - for (i = 0; i < sync_file->num_fences; ++i) { - fence_remove_callback(sync_file->cbs[i].fence, - &sync_file->cbs[i].cb); - fence_put(sync_file->cbs[i].fence); - }

+ fence_remove_callback(sync_file->fence, &sync_file->cb); + fence_put(sync_file->fence); kfree(sync_file); }

@@ -232,9 +277,9 @@ static unsigned int sync_file_poll(struct file *file, poll_table *wait)

poll_wait(file, &sync_file->wq, wait);

- status = atomic_read(&sync_file->status); + status = fence_is_signaled(sync_file->fence);

- if (!status) + if (status) return POLLIN; if (status < 0) return POLLERR; @@ -315,8 +360,9 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file, { struct sync_file_info info; struct sync_fence_info *fence_info = NULL; + struct fence **fences; __u32 size; - int ret, i; + int num_fences, ret, i;

if (copy_from_user(&info, (void __user *)arg, sizeof(info))) return -EFAULT; @@ -324,6 +370,8 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file, if (info.flags || info.pad) return -EINVAL;

+ fences = get_fences(sync_file, &num_fences); + /* * Passing num_fences = 0 means that userspace doesn't want to * retrieve any sync_fence_info. If num_fences = 0 we skip filling @@ -333,16 +381,16 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file, if (!info.num_fences) goto no_fences;

- if (info.num_fences < sync_file->num_fences) + if (info.num_fences < num_fences) return -EINVAL;

- size = sync_file->num_fences * sizeof(*fence_info); + size = num_fences * sizeof(*fence_info); fence_info = kzalloc(size, GFP_KERNEL); if (!fence_info) return -ENOMEM;

- for (i = 0; i < sync_file->num_fences; ++i) - sync_fill_fence_info(sync_file->cbs[i].fence, &fence_info[i]); + for (i = 0; i < num_fences; i++) + sync_fill_fence_info(fences[i], &fence_info[i]);

if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, size)) { @@ -352,11 +400,8 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,

no_fences: strlcpy(info.name, sync_file->name, sizeof(info.name)); - info.status = atomic_read(&sync_file->status); - if (info.status >= 0) - info.status = !info.status; - - info.num_fences = sync_file->num_fences; + info.status = fence_is_signaled(sync_file->fence); + info.num_fences = num_fences;

if (copy_to_user((void __user *)arg, &info, sizeof(info))) ret = -EFAULT; diff --git a/drivers/staging/android/sync_debug.c b/drivers/staging/android/sync_debug.c index 5f57499..0638a06 100644 --- a/drivers/staging/android/sync_debug.c +++ b/drivers/staging/android/sync_debug.c @@ -159,10 +159,15 @@ static void sync_print_sync_file(struct seq_file *s, int i;

seq_printf(s, "[%p] %s: %s\n", sync_file, sync_file->name, - sync_status_str(atomic_read(&sync_file->status))); - - for (i = 0; i < sync_file->num_fences; ++i) - sync_print_fence(s, sync_file->cbs[i].fence, true); + sync_status_str(!fence_is_signaled(sync_file->fence))); + + if (fence_is_array(sync_file->fence)) { + struct fence_array *array = to_fence_array(sync_file->fence); + for (i = 0; i < array->num_fences; ++i) + sync_print_fence(s, array->fences[i], true); + } else { + sync_print_fence(s, sync_file->fence, true); + } }

static int sync_debugfs_show(struct seq_file *s, void *unused) diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h index c6ffe8b..2efc5ec 100644 --- a/include/linux/sync_file.h +++ b/include/linux/sync_file.h @@ -19,12 +19,7 @@ #include <linux/list.h> #include <linux/spinlock.h> #include <linux/fence.h> - -struct sync_file_cb { - struct fence_cb cb; - struct fence *fence; - struct sync_file *sync_file; -}; +#include <linux/fence-array.h>

/** * struct sync_file - sync file to export to the userspace @@ -32,10 +27,9 @@ struct sync_file_cb { * @kref: reference count on fence. * @name: name of sync_file. Useful for debugging * @sync_file_list: membership in global file list - * @num_fences: number of sync_pts in the fence * @wq: wait queue for fence signaling - * @status: 0: signaled, >0:active, <0: error - * @cbs: sync_pts callback information + * @fence: fence with the fences in the sync_file + * @cb: fence callback information */ struct sync_file { struct file *file; @@ -44,12 +38,11 @@ struct sync_file { #ifdef CONFIG_DEBUG_FS struct list_head sync_file_list; #endif - int num_fences;

wait_queue_head_t wq; - atomic_t status;

- struct sync_file_cb cbs[]; + struct fence *fence; + struct fence_cb cb; };

struct sync_file *sync_file_create(struct fence *fence);