PCI: add pci_try_set_mwi

As suggested by Andrew, add pci_try_set_mwi(), which does not require
return-value checking.

- add pci_try_set_mwi() without __must_check
- make it return 0 on success, errno if the "try" failed or error
- review callers

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 24 insertions, 4 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d9fc1bd1f3e..35fa30aa306 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1186,6 +1186,11 @@ int pci_set_mwi(struct pci_dev *dev)
 	return 0;
 }
 
+int pci_try_set_mwi(struct pci_dev *dev)
+{
+	return 0;
+}
+
 void pci_clear_mwi(struct pci_dev *dev)
 {
 }
@@ -1242,9 +1247,7 @@ pci_set_cacheline_size(struct pci_dev *dev)
  * pci_set_mwi - enables memory-write-invalidate PCI transaction
  * @dev: the PCI device for which MWI is enabled
  *
- * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND,
- * and then calls @pcibios_set_mwi to do the needed arch specific
- * operations or a generic mwi-prep function.
+ * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND.
  *
  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
  */
@@ -1260,7 +1263,8 @@ pci_set_mwi(struct pci_dev *dev)
 
 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
 	if (! (cmd & PCI_COMMAND_INVALIDATE)) {
-		pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n", pci_name(dev));
+		pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n",
+			pci_name(dev));
 		cmd |= PCI_COMMAND_INVALIDATE;
 		pci_write_config_word(dev, PCI_COMMAND, cmd);
 	}
@@ -1269,6 +1273,21 @@ pci_set_mwi(struct pci_dev *dev)
 }
 
 /**
+ * pci_try_set_mwi - enables memory-write-invalidate PCI transaction
+ * @dev: the PCI device for which MWI is enabled
+ *
+ * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND.
+ * Callers are not required to check the return value.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int pci_try_set_mwi(struct pci_dev *dev)
+{
+	int rc = pci_set_mwi(dev);
+	return rc;
+}
+
+/**
  * pci_clear_mwi - disables Memory-Write-Invalidate for device dev
  * @dev: the PCI device to disable
  *
@@ -1600,6 +1619,7 @@ EXPORT_SYMBOL(pci_release_selected_regions);
 EXPORT_SYMBOL(pci_request_selected_regions);
 EXPORT_SYMBOL(pci_set_master);
 EXPORT_SYMBOL(pci_set_mwi);
+EXPORT_SYMBOL(pci_try_set_mwi);
 EXPORT_SYMBOL(pci_clear_mwi);
 EXPORT_SYMBOL_GPL(pci_intx);
 EXPORT_SYMBOL(pci_set_dma_mask);