1 files changed, 49 insertions, 7 deletions

diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index 571d9730fca..523626274c0 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -43,6 +43,12 @@
  * characters rather then a pointer to void.
  */
 
+/*
+ * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
+ * sets the number of pipeline buffers (length of the fsg_buffhd array).
+ * The valid range of num_buffers is: num >= 2 && num <= 4.
+ */
+
 
 #include <linux/usb/storage.h>
 #include <scsi/scsi.h>
@@ -238,6 +244,8 @@ struct fsg_lun {
 	u32		sense_data_info;
 	u32		unit_attention_data;
 
+	unsigned int	blkbits;	/* Bits of logical block size of bound block device */
+	unsigned int	blksize;	/* logical block size of bound block device */
 	struct device	dev;
 };
 
@@ -253,8 +261,31 @@ static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 #define EP0_BUFSIZE	256
 #define DELAYED_STATUS	(EP0_BUFSIZE + 999)	/* An impossibly large value */
 
-/* Number of buffers we will use.  2 is enough for double-buffering */
-#define FSG_NUM_BUFFERS	2
+#ifdef CONFIG_USB_GADGET_DEBUG_FILES
+
+static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
+module_param_named(num_buffers, fsg_num_buffers, uint, S_IRUGO);
+MODULE_PARM_DESC(num_buffers, "Number of pipeline buffers");
+
+#else
+
+/*
+ * Number of buffers we will use.
+ * 2 is usually enough for good buffering pipeline
+ */
+#define fsg_num_buffers	CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
+
+#endif /* CONFIG_USB_DEBUG */
+
+/* check if fsg_num_buffers is within a valid range */
+static inline int fsg_num_buffers_validate(void)
+{
+	if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4)
+		return 0;
+	pr_err("fsg_num_buffers %u is out of range (%d to %d)\n",
+	       fsg_num_buffers, 2 ,4);
+	return -EINVAL;
+}
 
 /* Default size of buffer length. */
 #define FSG_BUFLEN	((u32)16384)
@@ -571,13 +602,24 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 		rc = (int) size;
 		goto out;
 	}
-	num_sectors = size >> 9;	/* File size in 512-byte blocks */
+
+	if (curlun->cdrom) {
+		curlun->blksize = 2048;
+		curlun->blkbits = 11;
+	} else if (inode->i_bdev) {
+		curlun->blksize = bdev_logical_block_size(inode->i_bdev);
+		curlun->blkbits = blksize_bits(curlun->blksize);
+	} else {
+		curlun->blksize = 512;
+		curlun->blkbits = 9;
+	}
+
+	num_sectors = size >> curlun->blkbits; /* File size in logic-block-size blocks */
 	min_sectors = 1;
 	if (curlun->cdrom) {
-		num_sectors &= ~3;	/* Reduce to a multiple of 2048 */
-		min_sectors = 300*4;	/* Smallest track is 300 frames */
-		if (num_sectors >= 256*60*75*4) {
-			num_sectors = (256*60*75 - 1) * 4;
+		min_sectors = 300;	/* Smallest track is 300 frames */
+		if (num_sectors >= 256*60*75) {
+			num_sectors = 256*60*75 - 1;
 			LINFO(curlun, "file too big: %s\n", filename);
 			LINFO(curlun, "using only first %d blocks\n",
 					(int) num_sectors);