usb: gadget: fix MIDI gadget jack allocation

The dynamic jack allocation of the MIDI gadget currently links all
external jacks to one single instance of an embedded jack. According to
the spec, this is only valid if these streams always carry the same data
stream, as described in the USB MIDI 1.0 spec, chapter 3.3.1.

Also, genius Windows 7(tm) terminates it's life cycle instantly with a
blue screen of death once a device with more than one input and output
port with the current implementation is connected.

While at it, and because it grew again by this change, allocate the
temporary function pointer list on the heap, not on the stack.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 65 insertions, 73 deletions

diff --git a/drivers/usb/gadget/f_midi.c b/drivers/usb/gadget/f_midi.c
index 67b222908cf9..3797b3d6c622 100644
--- a/drivers/usb/gadget/f_midi.c
+++ b/drivers/usb/gadget/f_midi.c
@@ -95,7 +95,6 @@ static void f_midi_transmit(struct f_midi *midi, struct usb_request *req);
 
 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
 DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
-DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(16);
 DECLARE_USB_MS_ENDPOINT_DESCRIPTOR(16);
 
 /* B.3.1  Standard AC Interface Descriptor */
@@ -140,26 +139,6 @@ static struct usb_ms_header_descriptor ms_header_desc __initdata = {
         /* .wTotalLength =      DYNAMIC */
 };
 
-/* B.4.3  Embedded MIDI IN Jack Descriptor */
-static struct usb_midi_in_jack_descriptor jack_in_emb_desc = {
-        .bLength =            USB_DT_MIDI_IN_SIZE,
-        .bDescriptorType =      USB_DT_CS_INTERFACE,
-        .bDescriptorSubtype =   USB_MS_MIDI_IN_JACK,
-        .bJackType =        USB_MS_EMBEDDED,
-        /* .bJackID =           DYNAMIC */
-};
-
-/* B.4.4  Embedded MIDI OUT Jack Descriptor */
-static struct usb_midi_out_jack_descriptor_16 jack_out_emb_desc = {
-        /* .bLength =           DYNAMIC */
-        .bDescriptorType =      USB_DT_CS_INTERFACE,
-        .bDescriptorSubtype =   USB_MS_MIDI_OUT_JACK,
-        .bJackType =            USB_MS_EMBEDDED,
-        /* .bJackID =           DYNAMIC */
-        /* .bNrInputPins =      DYNAMIC */
-        /* .pins =              DYNAMIC */
-};
-
 /* B.5.1  Standard Bulk OUT Endpoint Descriptor */
 static struct usb_endpoint_descriptor bulk_out_desc = {
         .bLength =              USB_DT_ENDPOINT_AUDIO_SIZE,
@@ -758,9 +737,11 @@ fail:
 static int __init
 f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 {
-        struct usb_descriptor_header *midi_function[(MAX_PORTS * 2) + 12];
+        struct usb_descriptor_header **midi_function;
         struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
+        struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
         struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
+        struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
         struct usb_composite_dev *cdev = c->cdev;
         struct f_midi *midi = func_to_midi(f);
         int status, n, jack = 1, i = 0;
@@ -798,6 +779,14 @@ f_midi_bind(struct usb_configuration *c, struct usb_function *f)
                 goto fail;
         midi->out_ep->driver_data = cdev;       /* claim */
 
+        /* allocate temporary function list */
+        midi_function = kcalloc((MAX_PORTS * 4) + 9, sizeof(midi_function),
+                                GFP_KERNEL);
+        if (!midi_function) {
+                status = -ENOMEM;
+                goto fail;
+        }
+
         /*
          * construct the function's descriptor set. As the number of
          * input and output MIDI ports is configurable, we have to do
@@ -811,73 +800,74 @@ f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 
         /* calculate the header's wTotalLength */
         n = USB_DT_MS_HEADER_SIZE
-                + (1 + midi->in_ports) * USB_DT_MIDI_IN_SIZE
-                + (1 + midi->out_ports) * USB_DT_MIDI_OUT_SIZE(1);
+                + (midi->in_ports + midi->out_ports) *
+                        (USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
         ms_header_desc.wTotalLength = cpu_to_le16(n);
 
         midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
 
-        /* we have one embedded IN jack */
-        jack_in_emb_desc.bJackID = jack++;
-        midi_function[i++] = (struct usb_descriptor_header *) &jack_in_emb_desc;
-
-        /* and a dynamic amount of external IN jacks */
-        for (n = 0; n < midi->in_ports; n++) {
-                struct usb_midi_in_jack_descriptor *ext = &jack_in_ext_desc[n];
-
-                ext->bLength =                  USB_DT_MIDI_IN_SIZE;
-                ext->bDescriptorType =          USB_DT_CS_INTERFACE;
-                ext->bDescriptorSubtype =       USB_MS_MIDI_IN_JACK;
-                ext->bJackType =                USB_MS_EXTERNAL;
-                ext->bJackID =                  jack++;
-                ext->iJack =                    0;
-
-                midi_function[i++] = (struct usb_descriptor_header *) ext;
-        }
-
-        /* one embedded OUT jack ... */
-        jack_out_emb_desc.bLength = USB_DT_MIDI_OUT_SIZE(midi->in_ports);
-        jack_out_emb_desc.bJackID = jack++;
-        jack_out_emb_desc.bNrInputPins = midi->in_ports;
-        /* ... which referencess all external IN jacks */
+        /* configure the external IN jacks, each linked to an embedded OUT jack */
         for (n = 0; n < midi->in_ports; n++) {
-                jack_out_emb_desc.pins[n].baSourceID = jack_in_ext_desc[n].bJackID;
-                jack_out_emb_desc.pins[n].baSourcePin = 1;
+                struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
+                struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
+
+                in_ext->bLength                 = USB_DT_MIDI_IN_SIZE;
+                in_ext->bDescriptorType         = USB_DT_CS_INTERFACE;
+                in_ext->bDescriptorSubtype      = USB_MS_MIDI_IN_JACK;
+                in_ext->bJackType               = USB_MS_EXTERNAL;
+                in_ext->bJackID                 = jack++;
+                in_ext->iJack                   = 0;
+                midi_function[i++] = (struct usb_descriptor_header *) in_ext;
+
+                out_emb->bLength                = USB_DT_MIDI_OUT_SIZE(1);
+                out_emb->bDescriptorType        = USB_DT_CS_INTERFACE;
+                out_emb->bDescriptorSubtype     = USB_MS_MIDI_OUT_JACK;
+                out_emb->bJackType              = USB_MS_EMBEDDED;
+                out_emb->bJackID                = jack++;
+                out_emb->bNrInputPins           = 1;
+                out_emb->pins[0].baSourcePin    = 1;
+                out_emb->pins[0].baSourceID     = in_ext->bJackID;
+                out_emb->iJack                  = 0;
+                midi_function[i++] = (struct usb_descriptor_header *) out_emb;
+
+                /* link it to the endpoint */
+                ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
         }
 
-        midi_function[i++] = (struct usb_descriptor_header *) &jack_out_emb_desc;
-
-        /* and multiple external OUT jacks ... */
+        /* configure the external OUT jacks, each linked to an embedded IN jack */
         for (n = 0; n < midi->out_ports; n++) {
-                struct usb_midi_out_jack_descriptor_1 *ext = &jack_out_ext_desc[n];
-                int m;
-
-                ext->bLength =                  USB_DT_MIDI_OUT_SIZE(1);
-                ext->bDescriptorType =          USB_DT_CS_INTERFACE;
-                ext->bDescriptorSubtype =       USB_MS_MIDI_OUT_JACK;
-                ext->bJackType =                USB_MS_EXTERNAL;
-                ext->bJackID =                  jack++;
-                ext->bNrInputPins =             1;
-                ext->iJack =                    0;
-                /* ... which all reference the same embedded IN jack */
-                for (m = 0; m < midi->out_ports; m++) {
-                        ext->pins[m].baSourceID =       jack_in_emb_desc.bJackID;
-                        ext->pins[m].baSourcePin =      1;
-                }
-
-                midi_function[i++] = (struct usb_descriptor_header *) ext;
+                struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
+                struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
+
+                in_emb->bLength                 = USB_DT_MIDI_IN_SIZE;
+                in_emb->bDescriptorType         = USB_DT_CS_INTERFACE;
+                in_emb->bDescriptorSubtype      = USB_MS_MIDI_IN_JACK;
+                in_emb->bJackType               = USB_MS_EMBEDDED;
+                in_emb->bJackID                 = jack++;
+                in_emb->iJack                   = 0;
+                midi_function[i++] = (struct usb_descriptor_header *) in_emb;
+
+                out_ext->bLength =              USB_DT_MIDI_OUT_SIZE(1);
+                out_ext->bDescriptorType =      USB_DT_CS_INTERFACE;
+                out_ext->bDescriptorSubtype =   USB_MS_MIDI_OUT_JACK;
+                out_ext->bJackType =            USB_MS_EXTERNAL;
+                out_ext->bJackID =              jack++;
+                out_ext->bNrInputPins =         1;
+                out_ext->iJack =                0;
+                out_ext->pins[0].baSourceID =   in_emb->bJackID;
+                out_ext->pins[0].baSourcePin =  1;
+                midi_function[i++] = (struct usb_descriptor_header *) out_ext;
+
+                /* link it to the endpoint */
+                ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
         }
 
         /* configure the endpoint descriptors ... */
         ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
         ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
-        for (n = 0; n < midi->in_ports; n++)
-                ms_out_desc.baAssocJackID[n] = jack_in_emb_desc.bJackID;
 
         ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
         ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
-        for (n = 0; n < midi->out_ports; n++)
-                ms_in_desc.baAssocJackID[n] = jack_out_emb_desc.bJackID;
 
         /* ... and add them to the list */
         midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
@@ -901,6 +891,8 @@ f_midi_bind(struct usb_configuration *c, struct usb_function *f)
                 f->descriptors = usb_copy_descriptors(midi_function);
         }
 
+        kfree(midi_function);
+
         return 0;
 
 fail: