Commit baa12e5f authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/peer-to-peer' 

  - Clean up P2PDMA documentation (Randy Dunlap)

* pci/peer-to-peer:
  PCI/P2PDMA: Clean up documentation and kernel-doc
parents e6397dfc fcf9ab35

Documentation/driver-api/pci/p2pdma.rst

+2 −2
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ For example, in the NVMe Target Copy Offload implementation: 
  in that it exposes any CMB (Controller Memory Buffer) as a P2P memory

  resource (provider), it accepts P2P memory pages as buffers in requests

  to be used directly (client) and it can also make use of the CMB as

  submission queue entries (orchastrator).

  submission queue entries (orchestrator).

* The RDMA driver is a client in this arrangement so that an RNIC

  can DMA directly to the memory exposed by the NVMe device.

* The NVMe Target driver (nvmet) can orchestrate the data from the RNIC
@@ -111,7 +111,7 @@ that's compatible with all clients using :c:func:`pci_p2pmem_find()`. 
If more than one provider is supported, the one nearest to all the clients will

be chosen first. If more than one provider is an equal distance away, the

one returned will be chosen at random (it is not an arbitrary but

truely random). This function returns the PCI device to use for the provider

truly random). This function returns the PCI device to use for the provider

with a reference taken and therefore when it's no longer needed it should be

returned with pci_dev_put().

drivers/pci/p2pdma.c

+7 −7
Original line number Diff line number Diff line
@@ -422,7 +422,7 @@ static int upstream_bridge_distance_warn(struct pci_dev *provider, 
 *

 * Returns -1 if any of the clients are not compatible (behind the same

 * root port as the provider), otherwise returns a positive number where

 * a lower number is the preferrable choice. (If there's one client

 * a lower number is the preferable choice. (If there's one client

 * that's the same as the provider it will return 0, which is best choice).

 *

 * For now, "compatible" means the provider and the clients are all behind
@@ -493,7 +493,7 @@ EXPORT_SYMBOL_GPL(pci_has_p2pmem); 
 * @num_clients: number of client devices in the list

 *

 * If multiple devices are behind the same switch, the one "closest" to the

 * client devices in use will be chosen first. (So if one of the providers are

 * client devices in use will be chosen first. (So if one of the providers is

 * the same as one of the clients, that provider will be used ahead of any

 * other providers that are unrelated). If multiple providers are an equal

 * distance away, one will be chosen at random.
@@ -580,7 +580,7 @@ EXPORT_SYMBOL_GPL(pci_alloc_p2pmem); 
 * pci_free_p2pmem - free peer-to-peer DMA memory

 * @pdev: the device the memory was allocated from

 * @addr: address of the memory that was allocated

 * @size: number of bytes that was allocated

 * @size: number of bytes that were allocated

 */

void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)

{
@@ -617,7 +617,7 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_virt_to_bus); 
 * @nents: the number of SG entries in the list

 * @length: number of bytes to allocate

 *

 * Returns 0 on success

 * Return: %NULL on error or &struct scatterlist pointer and @nents on success

 */

struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev,

					 unsigned int *nents, u32 length)
@@ -673,7 +673,7 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_free_sgl); 
 *

 * Published memory can be used by other PCI device drivers for

 * peer-2-peer DMA operations. Non-published memory is reserved for

 * exlusive use of the device driver that registers the peer-to-peer

 * exclusive use of the device driver that registers the peer-to-peer

 * memory.

 */

void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
@@ -733,7 +733,7 @@ EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg); 
 * @use_p2pdma: returns whether to enable p2pdma or not

 *

 * Parses an attribute value to decide whether to enable p2pdma.

 * The value can select a PCI device (using it's full BDF device

 * The value can select a PCI device (using its full BDF device

 * name) or a boolean (in any format strtobool() accepts). A false

 * value disables p2pdma, a true value expects the caller

 * to automatically find a compatible device and specifying a PCI device
@@ -784,7 +784,7 @@ EXPORT_SYMBOL_GPL(pci_p2pdma_enable_store); 
 *		whether p2pdma is enabled

 * @page: contents of the stored value

 * @p2p_dev: the selected p2p device (NULL if no device is selected)

 * @use_p2pdma: whether p2pdme has been enabled

 * @use_p2pdma: whether p2pdma has been enabled

 *

 * Attributes that use pci_p2pdma_enable_store() should use this function

 * to show the value of the attribute.