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Minor dma-buf updates for 4.7:
- use of vma_pages instead of explicit computation. - DocBook and headerdoc updates for dma-buf. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJXTnlHAAoJEAG+/NWsLn5b/NUQAJHV0vNseAmwNDU02nUX/2bK h6nTLFzGsc8jiRfbay9WcQWMOHOmyGyT8llwJxdgDqRHV5THCWZ/MaMwGLUPjK80 INN2GIq6unvuRSUcTRsG+DahOIbqIOGtBzd7rBizxW7afk/Y2aJU9JWyQGKPqVVb fb6X9/GNKNXsQQUx6oF2mQIexso9F4++jN0S9oJGQL23MyR05leNmYFCPv1hwjdF Jc39SLkPqGe0v31zwl0QU0wB/8Ay2xY68GskIVGxohOj36RxTbPs74XJlnAUrZAX zNAzdcynGiBqMn4VE+4nWAWbSQnHObJkDKuuZNRLgwQZbFygDpfzIBWAsnfTROAE HJL1lsrCRcAHgcwoMu/ZSBsLSrR4nmpeqBPZVii9G62SCLO0YysTa6LKo2faGczF 1po6ZX+TFmRRmUffLaq5u4wlEtnma/HpDCeydYX8T2NGWt7pRBdpWk4j42SFAV1G SdkzjLzhIS/EjxEvHWZItQkq0JMpiPfh3AxYcKhd/oMOcBizDn0+BY6f6FgtRG9g 7JCzJ0/RJXHyfAJfapmNphb7zie/Pltzb1gVXarS314QtalLika4C35GUnC7vcDt AB7CNq63fMsLvQ9KLhO7DXztVC08zwk5jyRR7hmIJVF0hgVNYEnF3EGyVtYA5THI bUl+iSQrBVI08mxDxCM2 =XMBK -----END PGP SIGNATURE----- Merge tag 'dma-buf-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/sumits/dma-buf Pull dma-buf updates from Sumit Semwal: - use of vma_pages instead of explicit computation - DocBook and headerdoc updates for dma-buf * tag 'dma-buf-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/sumits/dma-buf: dma-buf: use vma_pages() fence: add missing descriptions for fence doc: update/fixup dma-buf related DocBook reservation: add headerdoc comments dma-buf: headerdoc fixes
This commit is contained in:
Linus Torvalds
commit
ebb8cb2bae
@ -128,16 +128,44 @@ X!Edrivers/base/interface.c
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!Edrivers/base/platform.c
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!Edrivers/base/bus.c
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</sect1>
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<sect1><title>Device Drivers DMA Management</title>
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<sect1>
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<title>Buffer Sharing and Synchronization</title>
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<para>
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The dma-buf subsystem provides the framework for sharing buffers
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for hardware (DMA) access across multiple device drivers and
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subsystems, and for synchronizing asynchronous hardware access.
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</para>
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<para>
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This is used, for example, by drm "prime" multi-GPU support, but
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is of course not limited to GPU use cases.
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</para>
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<para>
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The three main components of this are: (1) dma-buf, representing
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a sg_table and exposed to userspace as a file descriptor to allow
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passing between devices, (2) fence, which provides a mechanism
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to signal when one device as finished access, and (3) reservation,
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which manages the shared or exclusive fence(s) associated with
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the buffer.
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</para>
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<sect2><title>dma-buf</title>
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!Edrivers/dma-buf/dma-buf.c
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!Edrivers/dma-buf/fence.c
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!Edrivers/dma-buf/seqno-fence.c
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!Iinclude/linux/fence.h
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!Iinclude/linux/seqno-fence.h
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!Iinclude/linux/dma-buf.h
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</sect2>
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<sect2><title>reservation</title>
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!Pdrivers/dma-buf/reservation.c Reservation Object Overview
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!Edrivers/dma-buf/reservation.c
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!Iinclude/linux/reservation.h
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</sect2>
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<sect2><title>fence</title>
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!Edrivers/dma-buf/fence.c
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!Iinclude/linux/fence.h
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!Edrivers/dma-buf/seqno-fence.c
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!Iinclude/linux/seqno-fence.h
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!Edrivers/dma-buf/sync_file.c
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!Iinclude/linux/sync_file.h
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</sect2>
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</sect1>
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<sect1><title>Device Drivers DMA Management</title>
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!Edrivers/base/dma-coherent.c
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!Edrivers/base/dma-mapping.c
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</sect1>
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@ -33,6 +33,7 @@
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#include <linux/seq_file.h>
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#include <linux/poll.h>
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#include <linux/reservation.h>
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#include <linux/mm.h>
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#include <uapi/linux/dma-buf.h>
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@ -90,7 +91,7 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
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dmabuf = file->private_data;
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/* check for overflowing the buffer's size */
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if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
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if (vma->vm_pgoff + vma_pages(vma) >
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dmabuf->size >> PAGE_SHIFT)
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return -EINVAL;
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@ -723,11 +724,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
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return -EINVAL;
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/* check for offset overflow */
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if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
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if (pgoff + vma_pages(vma) < pgoff)
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return -EOVERFLOW;
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/* check for overflowing the buffer's size */
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if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
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if (pgoff + vma_pages(vma) >
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dmabuf->size >> PAGE_SHIFT)
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return -EINVAL;
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@ -35,6 +35,17 @@
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#include <linux/reservation.h>
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#include <linux/export.h>
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/**
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* DOC: Reservation Object Overview
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*
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* The reservation object provides a mechanism to manage shared and
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* exclusive fences associated with a buffer. A reservation object
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* can have attached one exclusive fence (normally associated with
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* write operations) or N shared fences (read operations). The RCU
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* mechanism is used to protect read access to fences from locked
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* write-side updates.
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*/
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DEFINE_WW_CLASS(reservation_ww_class);
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EXPORT_SYMBOL(reservation_ww_class);
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@ -43,9 +54,17 @@ EXPORT_SYMBOL(reservation_seqcount_class);
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const char reservation_seqcount_string[] = "reservation_seqcount";
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EXPORT_SYMBOL(reservation_seqcount_string);
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/*
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* Reserve space to add a shared fence to a reservation_object,
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* must be called with obj->lock held.
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/**
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* reservation_object_reserve_shared - Reserve space to add a shared
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* fence to a reservation_object.
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* @obj: reservation object
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*
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* Should be called before reservation_object_add_shared_fence(). Must
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* be called with obj->lock held.
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*
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* RETURNS
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* Zero for success, or -errno
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*/
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int reservation_object_reserve_shared(struct reservation_object *obj)
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{
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@ -180,7 +199,11 @@ done:
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fence_put(old_fence);
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}
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/*
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/**
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* reservation_object_add_shared_fence - Add a fence to a shared slot
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* @obj: the reservation object
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* @fence: the shared fence to add
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*
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* Add a fence to a shared slot, obj->lock must be held, and
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* reservation_object_reserve_shared_fence has been called.
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*/
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@ -200,6 +223,13 @@ void reservation_object_add_shared_fence(struct reservation_object *obj,
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}
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EXPORT_SYMBOL(reservation_object_add_shared_fence);
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/**
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* reservation_object_add_excl_fence - Add an exclusive fence.
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* @obj: the reservation object
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* @fence: the shared fence to add
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*
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* Add a fence to the exclusive slot. The obj->lock must be held.
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*/
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void reservation_object_add_excl_fence(struct reservation_object *obj,
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struct fence *fence)
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{
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@ -233,6 +263,18 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
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}
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EXPORT_SYMBOL(reservation_object_add_excl_fence);
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/**
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* reservation_object_get_fences_rcu - Get an object's shared and exclusive
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* fences without update side lock held
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* @obj: the reservation object
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* @pfence_excl: the returned exclusive fence (or NULL)
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* @pshared_count: the number of shared fences returned
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* @pshared: the array of shared fence ptrs returned (array is krealloc'd to
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* the required size, and must be freed by caller)
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*
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* RETURNS
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* Zero or -errno
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*/
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int reservation_object_get_fences_rcu(struct reservation_object *obj,
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struct fence **pfence_excl,
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unsigned *pshared_count,
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@ -319,6 +361,18 @@ unlock:
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}
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EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);
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/**
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* reservation_object_wait_timeout_rcu - Wait on reservation's objects
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* shared and/or exclusive fences.
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* @obj: the reservation object
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* @wait_all: if true, wait on all fences, else wait on just exclusive fence
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* @intr: if true, do interruptible wait
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* @timeout: timeout value in jiffies or zero to return immediately
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*
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* RETURNS
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* Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
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* greater than zer on success.
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*/
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long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
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bool wait_all, bool intr,
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unsigned long timeout)
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@ -416,6 +470,16 @@ reservation_object_test_signaled_single(struct fence *passed_fence)
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return ret;
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}
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/**
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* reservation_object_test_signaled_rcu - Test if a reservation object's
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* fences have been signaled.
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* @obj: the reservation object
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* @test_all: if true, test all fences, otherwise only test the exclusive
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* fence
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*
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* RETURNS
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* true if all fences signaled, else false
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*/
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bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
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bool test_all)
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{
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@ -112,19 +112,24 @@ struct dma_buf_ops {
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* @file: file pointer used for sharing buffers across, and for refcounting.
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* @attachments: list of dma_buf_attachment that denotes all devices attached.
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* @ops: dma_buf_ops associated with this buffer object.
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* @lock: used internally to serialize list manipulation, attach/detach and vmap/unmap
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* @vmapping_counter: used internally to refcnt the vmaps
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* @vmap_ptr: the current vmap ptr if vmapping_counter > 0
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* @exp_name: name of the exporter; useful for debugging.
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* @owner: pointer to exporter module; used for refcounting when exporter is a
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* kernel module.
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* @list_node: node for dma_buf accounting and debugging.
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* @priv: exporter specific private data for this buffer object.
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* @resv: reservation object linked to this dma-buf
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* @poll: for userspace poll support
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* @cb_excl: for userspace poll support
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* @cb_shared: for userspace poll support
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*/
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struct dma_buf {
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size_t size;
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struct file *file;
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struct list_head attachments;
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const struct dma_buf_ops *ops;
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/* mutex to serialize list manipulation, attach/detach and vmap/unmap */
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struct mutex lock;
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unsigned vmapping_counter;
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void *vmap_ptr;
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@ -188,9 +193,11 @@ struct dma_buf_export_info {
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/**
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* helper macro for exporters; zeros and fills in most common values
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*
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* @name: export-info name
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*/
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#define DEFINE_DMA_BUF_EXPORT_INFO(a) \
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struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME, \
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#define DEFINE_DMA_BUF_EXPORT_INFO(name) \
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struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \
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.owner = THIS_MODULE }
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/**
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@ -49,6 +49,8 @@ struct fence_cb;
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* @timestamp: Timestamp when the fence was signaled.
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* @status: Optional, only valid if < 0, must be set before calling
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* fence_signal, indicates that the fence has completed with an error.
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* @child_list: list of children fences
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* @active_list: list of active fences
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*
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* the flags member must be manipulated and read using the appropriate
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* atomic ops (bit_*), so taking the spinlock will not be needed most
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@ -49,12 +49,27 @@ extern struct ww_class reservation_ww_class;
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extern struct lock_class_key reservation_seqcount_class;
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extern const char reservation_seqcount_string[];
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/**
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* struct reservation_object_list - a list of shared fences
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* @rcu: for internal use
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* @shared_count: table of shared fences
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* @shared_max: for growing shared fence table
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* @shared: shared fence table
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*/
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struct reservation_object_list {
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struct rcu_head rcu;
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u32 shared_count, shared_max;
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struct fence __rcu *shared[];
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};
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/**
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* struct reservation_object - a reservation object manages fences for a buffer
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* @lock: update side lock
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* @seq: sequence count for managing RCU read-side synchronization
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* @fence_excl: the exclusive fence, if there is one currently
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* @fence: list of current shared fences
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* @staged: staged copy of shared fences for RCU updates
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*/
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struct reservation_object {
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struct ww_mutex lock;
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seqcount_t seq;
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@ -68,6 +83,10 @@ struct reservation_object {
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#define reservation_object_assert_held(obj) \
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lockdep_assert_held(&(obj)->lock.base)
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/**
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* reservation_object_init - initialize a reservation object
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* @obj: the reservation object
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*/
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static inline void
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reservation_object_init(struct reservation_object *obj)
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{
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@ -79,6 +98,10 @@ reservation_object_init(struct reservation_object *obj)
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obj->staged = NULL;
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}
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/**
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* reservation_object_fini - destroys a reservation object
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* @obj: the reservation object
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*/
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static inline void
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reservation_object_fini(struct reservation_object *obj)
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{
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@ -106,6 +129,14 @@ reservation_object_fini(struct reservation_object *obj)
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ww_mutex_destroy(&obj->lock);
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}
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/**
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* reservation_object_get_list - get the reservation object's
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* shared fence list, with update-side lock held
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* @obj: the reservation object
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*
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* Returns the shared fence list. Does NOT take references to
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* the fence. The obj->lock must be held.
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*/
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static inline struct reservation_object_list *
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reservation_object_get_list(struct reservation_object *obj)
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{
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@ -113,6 +144,17 @@ reservation_object_get_list(struct reservation_object *obj)
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reservation_object_held(obj));
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}
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/**
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* reservation_object_get_excl - get the reservation object's
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* exclusive fence, with update-side lock held
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* @obj: the reservation object
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*
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* Returns the exclusive fence (if any). Does NOT take a
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* reference. The obj->lock must be held.
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*
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* RETURNS
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* The exclusive fence or NULL
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*/
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static inline struct fence *
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reservation_object_get_excl(struct reservation_object *obj)
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{
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@ -120,6 +162,17 @@ reservation_object_get_excl(struct reservation_object *obj)
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reservation_object_held(obj));
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}
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/**
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* reservation_object_get_excl_rcu - get the reservation object's
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* exclusive fence, without lock held.
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* @obj: the reservation object
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*
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* If there is an exclusive fence, this atomically increments it's
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* reference count and returns it.
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*
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* RETURNS
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* The exclusive fence or NULL if none
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*/
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static inline struct fence *
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reservation_object_get_excl_rcu(struct reservation_object *obj)
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{
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