USB: g_mass_storage: constant length buffers used

Using version of fsg_buffhd structure with buf field being an
array of characters with predefined size.  Since mass storage
function does not define changing buffer size on run-time it is
not required for the field to be a pointer to void and allocating
space dynamically.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 7750346b696c6e728ad4981aa01d64d0eb678249..b4ec76a3e37dc27065efd74d59937f81c2b2b0a9 100644 (file)
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -258,6 +258,7 @@ static const char fsg_string_interface[] = "Mass Storage";
 
 
 #define FSG_NO_INTR_EP 1
+#define FSG_BUFFHD_STATIC_BUFFER 1
 
 #include "storage_common.c"
 
@@ -1894,9 +1895,8 @@ static int send_status(struct fsg_dev *fsg)
                                SK(sd), ASC(sd), ASCQ(sd), sdinfo);
        }
 
-
        /* Store and send the Bulk-only CSW */
-       csw = bh->buf;
+       csw = (void*)bh->buf;
 
        csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
        csw->Tag = fsg->tag;
@@ -2808,10 +2808,6 @@ static void /* __init_or_exit */ fsg_unbind(struct usb_gadget *gadget)
                complete(&fsg->thread_notifier);
        }
 
-       /* Free the data buffers */
-       for (i = 0; i < FSG_NUM_BUFFERS; ++i)
-               kfree(fsg->common->buffhds[i].buf);
-
        /* Free the request and buffer for endpoint 0 */
        if (req) {
                kfree(req->buf);
@@ -2978,20 +2974,6 @@ static int __init fsg_bind(struct usb_gadget *gadget)
                goto out;
        req->complete = ep0_complete;
 
-       /* Allocate the data buffers */
-       for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
-               struct fsg_buffhd       *bh = &fsg->common->buffhds[i];
-
-               /* Allocate for the bulk-in endpoint.  We assume that
-                * the buffer will also work with the bulk-out (and
-                * interrupt-in) endpoint. */
-               bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
-               if (!bh->buf)
-                       goto out;
-               bh->next = bh + 1;
-       }
-       fsg->common->buffhds[FSG_NUM_BUFFERS - 1].next = &fsg->common->buffhds[0];
-
        /* This should reflect the actual gadget power source */
        usb_gadget_set_selfpowered(gadget);
 
@@ -3087,6 +3069,8 @@ static struct usb_gadget_driver           fsg_driver = {
 static int __init fsg_alloc(void)
 {
        struct fsg_dev          *fsg;
+       struct fsg_buffhd       *bh;
+       unsigned                i;
 
        fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
        if (!fsg)
@@ -3098,6 +3082,13 @@ static int __init fsg_alloc(void)
                return -ENOMEM;
        }
 
+       bh = fsg->common->buffhds;
+       i = FSG_NUM_BUFFERS - 1;
+       do {
+               bh->next = bh + 1;
+       } while (++bh, --i);
+       bh->next = fsg->common->buffhds;
+
        spin_lock_init(&fsg->lock);
        init_rwsem(&fsg->common->filesem);
        init_completion(&fsg->thread_notifier);

diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index e76c8ced41e207e93df6b97d0aef4ae3fedd0542..60bc696778c941a4aac1eb136666616700cb0686 100644 (file)
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -47,6 +47,12 @@
  * When FSG_NO_OTG is defined fsg_otg_desc won't be defined.
  */
 
+/*
+ * When FSG_BUFFHD_STATIC_BUFFER is defined when this file is included
+ * the fsg_buffhd structure's buf field will be an array of FSG_BUFLEN
+ * characters rather then a pointer to void.
+ */
+
 
 #include <asm/unaligned.h>
 
@@ -290,7 +296,11 @@ enum fsg_buffer_state {
 };
 
 struct fsg_buffhd {
+#ifdef FSG_BUFFHD_STATIC_BUFFER
+       char                            buf[FSG_BUFLEN];
+#else
        void                            *buf;
+#endif
        enum fsg_buffer_state           state;
        struct fsg_buffhd               *next;