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 7750346..b4ec76a 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -258,6 +258,7 @@
#define FSG_NO_INTR_EP 1
+#define FSG_BUFFHD_STATIC_BUFFER 1
#include "storage_common.c"
@@ -1894,9 +1895,8 @@
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 @@
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 @@
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 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 @@
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 e76c8ce..60bc696 100644
--- 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 @@
};
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;