redonkable/alistair23-linux
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dma-buf: stop using the dmabuf->lock so much v2

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The attachment list is now protected by the dma_resv object.

Stop holding the dma_buf->lock while calling ->attach/->detach,
this allows for concurrent attach/detach operations.

v2: cleanup commit message and locking in _debug_show()

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/336790
This commit is contained in:
Christian König 2019-10-18 16:30:19 +02:00
parent 15fd552d18
commit f45f57cce5
1 changed files with 2 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
drivers/dma-buf/dma-buf.c
View file

@ -685,8 +685,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
attach->dmabuf = dmabuf;
attach->dynamic_mapping = dynamic_mapping;
mutex_lock(&dmabuf->lock);
if (dmabuf->ops->attach) {
ret = dmabuf->ops->attach(dmabuf, attach);
if (ret)
@ -696,8 +694,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
list_add(&attach->node, &dmabuf->attachments);
dma_resv_unlock(dmabuf->resv);
mutex_unlock(&dmabuf->lock);
/* When either the importer or the exporter can't handle dynamic
* mappings we cache the mapping here to avoid issues with the
* reservation object lock.
@ -726,7 +722,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
err_attach:
kfree(attach);
mutex_unlock(&dmabuf->lock);
return ERR_PTR(ret);
err_unlock:
@ -776,14 +771,12 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
dma_resv_unlock(attach->dmabuf->resv);
}
mutex_lock(&dmabuf->lock);
dma_resv_lock(dmabuf->resv, NULL);
list_del(&attach->node);
dma_resv_unlock(dmabuf->resv);
if (dmabuf->ops->detach)
dmabuf->ops->detach(dmabuf, attach);
mutex_unlock(&dmabuf->lock);
kfree(attach);
}
EXPORT_SYMBOL_GPL(dma_buf_detach);
@ -1248,13 +1241,9 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
list_for_each_entry(buf_obj, &db_list.head, list_node) {
ret = mutex_lock_interruptible(&buf_obj->lock);
if (ret)
goto error_unlock_list;
ret = dma_resv_lock_interruptible(buf_obj->resv, NULL);
if (ret)
goto error_unlock_buf;
goto error_unlock;
seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
buf_obj->size,
@ -1307,7 +1296,6 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
count++;
size += buf_obj->size;
mutex_unlock(&buf_obj->lock);
}
seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
@ -1315,9 +1303,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
mutex_unlock(&db_list.lock);
return 0;
error_unlock_buf:
mutex_unlock(&buf_obj->lock);
error_unlock_list:
error_unlock:
mutex_unlock(&db_list.lock);
return ret;
}