USB: xhci: Allow allocation of commands without input contexts.

The xhci_command structure is the basic structure for issuing commands to
the xHCI hardware.  It contains a struct completion (so that the issuing
function can wait on the command), command status, and a input context
that is used to pass information to the hardware.  Not all commands need
the input context, so make it optional to allocate.  Allow
xhci_free_container_ctx() to be passed a NULL input context, to make
freeing the xhci_command structure simple.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 15 insertions, 8 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index 451f53eec6d7..17f1caf2af64 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -1679,7 +1679,7 @@ int xhci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev,
                 xhci_warn(xhci, "Cannot update hub desc for unknown device.\n");
                 return -EINVAL;
         }
-        config_cmd = xhci_alloc_command(xhci, true, mem_flags);
+        config_cmd = xhci_alloc_command(xhci, true, true, mem_flags);
         if (!config_cmd) {
                 xhci_dbg(xhci, "Could not allocate xHCI command structure.\n");
                 return -ENOMEM;
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 1f1f8a0f2e66..8045bc69083d 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -267,6 +267,8 @@ struct xhci_container_ctx *xhci_alloc_container_ctx(struct xhci_hcd *xhci,
 void xhci_free_container_ctx(struct xhci_hcd *xhci,
                              struct xhci_container_ctx *ctx)
 {
+        if (!ctx)
+                return;
         dma_pool_free(xhci->device_pool, ctx->bytes, ctx->dma);
         kfree(ctx);
 }
@@ -844,7 +846,8 @@ static void scratchpad_free(struct xhci_hcd *xhci)
 }
 
 struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
-                bool allocate_completion, gfp_t mem_flags)
+                bool allocate_in_ctx, bool allocate_completion,
+                gfp_t mem_flags)
 {
         struct xhci_command *command;
 
@@ -852,11 +855,14 @@ struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
         if (!command)
                 return NULL;
 
-        command->in_ctx =
-                xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT, mem_flags);
-        if (!command->in_ctx) {
-                kfree(command);
-                return NULL;
+        if (allocate_in_ctx) {
+                command->in_ctx =
+                        xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT,
+                                        mem_flags);
+                if (!command->in_ctx) {
+                        kfree(command);
+                        return NULL;
+                }
         }
 
         if (allocate_completion) {
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 61747f3c5c8f..902be9647c60 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1237,7 +1237,8 @@ void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
                 struct xhci_virt_device *virt_dev,
                 unsigned int ep_index);
 struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
-                bool allocate_completion, gfp_t mem_flags);
+                bool allocate_in_ctx, bool allocate_completion,
+                gfp_t mem_flags);
 void xhci_free_command(struct xhci_hcd *xhci,
                 struct xhci_command *command);