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Commit ebb8cb2b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 6b15d665 b02da6f8

Documentation/DocBook/device-drivers.tmpl

+32 −4
Original line number Diff line number Diff line
@@ -128,16 +128,44 @@ X!Edrivers/base/interface.c 
!Edrivers/base/platform.c

!Edrivers/base/bus.c

     </sect1>

     <sect1><title>Device Drivers DMA Management</title>

     <sect1>

       <title>Buffer Sharing and Synchronization</title>

       <para>

         The dma-buf subsystem provides the framework for sharing buffers

         for hardware (DMA) access across multiple device drivers and

         subsystems, and for synchronizing asynchronous hardware access.

       </para>

       <para>

         This is used, for example, by drm "prime" multi-GPU support, but

         is of course not limited to GPU use cases.

       </para>

       <para>

         The three main components of this are: (1) dma-buf, representing

         a sg_table and exposed to userspace as a file descriptor to allow

         passing between devices, (2) fence, which provides a mechanism

         to signal when one device as finished access, and (3) reservation,

         which manages the shared or exclusive fence(s) associated with

         the buffer.

       </para>

       <sect2><title>dma-buf</title>

!Edrivers/dma-buf/dma-buf.c

!Iinclude/linux/dma-buf.h

       </sect2>

       <sect2><title>reservation</title>

!Pdrivers/dma-buf/reservation.c Reservation Object Overview

!Edrivers/dma-buf/reservation.c

!Iinclude/linux/reservation.h

       </sect2>

       <sect2><title>fence</title>

!Edrivers/dma-buf/fence.c

!Edrivers/dma-buf/seqno-fence.c

!Iinclude/linux/fence.h

!Edrivers/dma-buf/seqno-fence.c

!Iinclude/linux/seqno-fence.h

!Edrivers/dma-buf/reservation.c

!Iinclude/linux/reservation.h

!Edrivers/dma-buf/sync_file.c

!Iinclude/linux/sync_file.h

       </sect2>

     </sect1>

     <sect1><title>Device Drivers DMA Management</title>

!Edrivers/base/dma-coherent.c

!Edrivers/base/dma-mapping.c

     </sect1>

drivers/dma-buf/dma-buf.c

+4 −3
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <linux/seq_file.h>

#include <linux/poll.h>

#include <linux/reservation.h>

#include <linux/mm.h>



#include <uapi/linux/dma-buf.h>
@@ -90,7 +91,7 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) 
	dmabuf = file->private_data;



	/* check for overflowing the buffer's size */

	if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >

	if (vma->vm_pgoff + vma_pages(vma) >

	    dmabuf->size >> PAGE_SHIFT)

		return -EINVAL;
@@ -723,11 +724,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, 
		return -EINVAL;



	/* check for offset overflow */

	if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)

	if (pgoff + vma_pages(vma) < pgoff)

		return -EOVERFLOW;



	/* check for overflowing the buffer's size */

	if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >

	if (pgoff + vma_pages(vma) >

	    dmabuf->size >> PAGE_SHIFT)

		return -EINVAL;

drivers/dma-buf/reservation.c

+68 −4
Original line number Diff line number Diff line
@@ -35,6 +35,17 @@ 
#include <linux/reservation.h>

#include <linux/export.h>



/**

 * DOC: Reservation Object Overview

 *

 * The reservation object provides a mechanism to manage shared and

 * exclusive fences associated with a buffer.  A reservation object

 * can have attached one exclusive fence (normally associated with

 * write operations) or N shared fences (read operations).  The RCU

 * mechanism is used to protect read access to fences from locked

 * write-side updates.

 */



DEFINE_WW_CLASS(reservation_ww_class);

EXPORT_SYMBOL(reservation_ww_class);
@@ -43,9 +54,17 @@ 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.



/**

 * reservation_object_reserve_shared - Reserve space to add a shared

 * fence to a reservation_object.

 * @obj: reservation object

 *

 * Should be called before reservation_object_add_shared_fence().  Must

 * be called with obj->lock held.

 *

 * RETURNS

 * Zero for success, or -errno

 */

int reservation_object_reserve_shared(struct reservation_object *obj)

{
@@ -180,7 +199,11 @@ reservation_object_add_shared_replace(struct reservation_object *obj, 
		fence_put(old_fence);

}



/*

/**

 * reservation_object_add_shared_fence - Add a fence to a shared slot

 * @obj: the reservation object

 * @fence: the shared fence to add

 *

 * Add a fence to a shared slot, obj->lock must be held, and

 * reservation_object_reserve_shared_fence has been called.

 */
@@ -200,6 +223,13 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, 
}

EXPORT_SYMBOL(reservation_object_add_shared_fence);



/**

 * reservation_object_add_excl_fence - Add an exclusive fence.

 * @obj: the reservation object

 * @fence: the shared fence to add

 *

 * Add a fence to the exclusive slot.  The obj->lock must be held.

 */

void reservation_object_add_excl_fence(struct reservation_object *obj,

				       struct fence *fence)

{
@@ -233,6 +263,18 @@ void reservation_object_add_excl_fence(struct reservation_object *obj, 
}

EXPORT_SYMBOL(reservation_object_add_excl_fence);



/**

 * reservation_object_get_fences_rcu - Get an object's shared and exclusive

 * fences without update side lock held

 * @obj: the reservation object

 * @pfence_excl: the returned exclusive fence (or NULL)

 * @pshared_count: the number of shared fences returned

 * @pshared: the array of shared fence ptrs returned (array is krealloc'd to

 * the required size, and must be freed by caller)

 *

 * RETURNS

 * Zero or -errno

 */

int reservation_object_get_fences_rcu(struct reservation_object *obj,

				      struct fence **pfence_excl,

				      unsigned *pshared_count,
@@ -319,6 +361,18 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj, 
}

EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);



/**

 * reservation_object_wait_timeout_rcu - Wait on reservation's objects

 * shared and/or exclusive fences.

 * @obj: the reservation object

 * @wait_all: if true, wait on all fences, else wait on just exclusive fence

 * @intr: if true, do interruptible wait

 * @timeout: timeout value in jiffies or zero to return immediately

 *

 * RETURNS

 * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or

 * greater than zer on success.

 */

long reservation_object_wait_timeout_rcu(struct reservation_object *obj,

					 bool wait_all, bool intr,

					 unsigned long timeout)
@@ -416,6 +470,16 @@ reservation_object_test_signaled_single(struct fence *passed_fence) 
	return ret;

}



/**

 * reservation_object_test_signaled_rcu - Test if a reservation object's

 * fences have been signaled.

 * @obj: the reservation object

 * @test_all: if true, test all fences, otherwise only test the exclusive

 * fence

 *

 * RETURNS

 * true if all fences signaled, else false

 */

bool reservation_object_test_signaled_rcu(struct reservation_object *obj,

					  bool test_all)

{

include/linux/dma-buf.h

+10 −3
Original line number Diff line number Diff line
@@ -112,19 +112,24 @@ struct dma_buf_ops { 
 * @file: file pointer used for sharing buffers across, and for refcounting.

 * @attachments: list of dma_buf_attachment that denotes all devices attached.

 * @ops: dma_buf_ops associated with this buffer object.

 * @lock: used internally to serialize list manipulation, attach/detach and vmap/unmap

 * @vmapping_counter: used internally to refcnt the vmaps

 * @vmap_ptr: the current vmap ptr if vmapping_counter > 0

 * @exp_name: name of the exporter; useful for debugging.

 * @owner: pointer to exporter module; used for refcounting when exporter is a

 *         kernel module.

 * @list_node: node for dma_buf accounting and debugging.

 * @priv: exporter specific private data for this buffer object.

 * @resv: reservation object linked to this dma-buf

 * @poll: for userspace poll support

 * @cb_excl: for userspace poll support

 * @cb_shared: for userspace poll support

 */

struct dma_buf {

	size_t size;

	struct file *file;

	struct list_head attachments;

	const struct dma_buf_ops *ops;

	/* mutex to serialize list manipulation, attach/detach and vmap/unmap */

	struct mutex lock;

	unsigned vmapping_counter;

	void *vmap_ptr;
@@ -188,9 +193,11 @@ struct dma_buf_export_info { 


/**

 * helper macro for exporters; zeros and fills in most common values

 *

 * @name: export-info name

 */

#define DEFINE_DMA_BUF_EXPORT_INFO(a)	\

	struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME, \

#define DEFINE_DMA_BUF_EXPORT_INFO(name)	\

	struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \

					 .owner = THIS_MODULE }



/**

include/linux/fence.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ struct fence_cb; 
 * @timestamp: Timestamp when the fence was signaled.

 * @status: Optional, only valid if < 0, must be set before calling

 * fence_signal, indicates that the fence has completed with an error.

 * @child_list: list of children fences

 * @active_list: list of active fences

 *

 * the flags member must be manipulated and read using the appropriate

 * atomic ops (bit_*), so taking the spinlock will not be needed most