USB storage: sg chaining support

[PATCH] USB storage: sg chaining support

Modify usb_stor_access_xfer_buf() to take a pointer to an sg
entry pointer, so we can keep track of that instead of passing
around an integer index (which we can't use when dealing with
multiple scatterlist arrays).

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/drivers/usb/storage/sddr09.c b/drivers/usb/storage/sddr09.c
index b2ed2a3e6fca..b12202c5da2d 100644
--- a/drivers/usb/storage/sddr09.c
+++ b/drivers/usb/storage/sddr09.c
@@ -705,7 +705,8 @@ sddr09_read_data(struct us_data *us,
         unsigned char *buffer;
         unsigned int lba, maxlba, pba;
         unsigned int page, pages;
-        unsigned int len, index, offset;
+        unsigned int len, offset;
+        struct scatterlist *sg;
         int result;
 
         // Figure out the initial LBA and page
@@ -730,7 +731,8 @@ sddr09_read_data(struct us_data *us,
         // contiguous LBA's. Another exercise left to the student.
 
         result = 0;
-        index = offset = 0;
+        offset = 0;
+        sg = NULL;
 
         while (sectors > 0) {
 
@@ -777,7 +779,7 @@ sddr09_read_data(struct us_data *us,
 
                 // Store the data in the transfer buffer
                 usb_stor_access_xfer_buf(buffer, len, us->srb,
-                                &index, &offset, TO_XFER_BUF);
+                                &sg, &offset, TO_XFER_BUF);
 
                 page = 0;
                 lba++;
@@ -931,7 +933,8 @@ sddr09_write_data(struct us_data *us,
         unsigned int pagelen, blocklen;
         unsigned char *blockbuffer;
         unsigned char *buffer;
-        unsigned int len, index, offset;
+        unsigned int len, offset;
+        struct scatterlist *sg;
         int result;
 
         // Figure out the initial LBA and page
@@ -968,7 +971,8 @@ sddr09_write_data(struct us_data *us,
         }
 
         result = 0;
-        index = offset = 0;
+        offset = 0;
+        sg = NULL;
 
         while (sectors > 0) {
 
@@ -987,7 +991,7 @@ sddr09_write_data(struct us_data *us,
 
                 // Get the data from the transfer buffer
                 usb_stor_access_xfer_buf(buffer, len, us->srb,
-                                &index, &offset, FROM_XFER_BUF);
+                                &sg, &offset, FROM_XFER_BUF);
 
                 result = sddr09_write_lba(us, lba, page, pages,
                                 buffer, blockbuffer);