USB: Change the scatterlist type in struct urb

Change the type of the URB's 'sg' pointer from a usb_sg_request to
a scatterlist.  This allows drivers to submit scatter-gather lists
without using the usb_sg_wait() interface.  It has the added benefit
of removing the typecasts that were added as part of patch as1368 (and
slightly decreasing the number of pointer dereferences).

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

7 files changed, 12 insertions, 14 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 0abc5c537f39..297c92e4bf8d 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1278,7 +1278,7 @@ static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
         dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
         if (urb->transfer_flags & URB_DMA_MAP_SG)
                 dma_unmap_sg(hcd->self.controller,
-                                urb->sg->sg,
+                                urb->sg,
                                 urb->num_sgs,
                                 dir);
         else if (urb->transfer_flags & URB_DMA_MAP_PAGE)
@@ -1346,7 +1346,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
                         if (urb->num_sgs) {
                                 int n = dma_map_sg(
                                                 hcd->self.controller,
-                                                urb->sg->sg,
+                                                urb->sg,
                                                 urb->num_sgs,
                                                 dir);
                                 if (n <= 0)
@@ -1359,9 +1359,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
                                                         URB_DMA_SG_COMBINED;
                                 }
                         } else if (urb->sg) {
-                                struct scatterlist *sg;
-
-                                sg = (struct scatterlist *) urb->sg;
+                                struct scatterlist *sg = urb->sg;
                                 urb->transfer_dma = dma_map_page(
                                                 hcd->self.controller,
                                                 sg_page(sg),
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index d8329eb47d4f..63919b8abee1 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -413,7 +413,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
                                         sg->length;
                         }
                 }
-                io->urbs[0]->sg = io;
+                io->urbs[0]->sg = sg;
                 io->urbs[0]->num_sgs = io->entries;
                 io->entries = 1;
         } else {
@@ -454,7 +454,7 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
                         }
                         io->urbs[i]->transfer_buffer_length = len;
 
-                        io->urbs[i]->sg = (struct usb_sg_request *) sg;
+                        io->urbs[i]->sg = sg;
                 }
                 io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
         }
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 89521775c567..11a79c4f4a9d 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -663,7 +663,7 @@ qh_urb_transaction (
          */
         i = urb->num_sgs;
         if (len > 0 && i > 0) {
-                sg = urb->sg->sg;
+                sg = urb->sg;
                 buf = sg_dma_address(sg);
 
                 /* urb->transfer_buffer_length may be smaller than the
diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c
index b388dd1fb4c4..ab5a14fbfeeb 100644
--- a/drivers/usb/host/whci/qset.c
+++ b/drivers/usb/host/whci/qset.c
@@ -443,7 +443,7 @@ static int qset_add_urb_sg(struct whc *whc, struct whc_qset *qset, struct urb *u
 
         remaining = urb->transfer_buffer_length;
 
-        for_each_sg(urb->sg->sg, sg, urb->num_sgs, i) {
+        for_each_sg(urb->sg, sg, urb->num_sgs, i) {
                 dma_addr_t dma_addr;
                 size_t dma_remaining;
                 dma_addr_t sp, ep;
@@ -561,7 +561,7 @@ static int qset_add_urb_sg_linearize(struct whc *whc, struct whc_qset *qset,
 
         remaining = urb->transfer_buffer_length;
 
-        for_each_sg(urb->sg->sg, sg, urb->sg->nents, i) {
+        for_each_sg(urb->sg, sg, urb->num_sgs, i) {
                 size_t len;
                 size_t sg_remaining;
                 void *orig;
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9e27eb0c7004..a67caef265b1 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1788,7 +1788,7 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb)
 
         xhci_dbg(xhci, "count sg list trbs: \n");
         num_trbs = 0;
-        for_each_sg(urb->sg->sg, sg, num_sgs, i) {
+        for_each_sg(urb->sg, sg, num_sgs, i) {
                 unsigned int previous_total_trbs = num_trbs;
                 unsigned int len = sg_dma_len(sg);
 
@@ -1951,7 +1951,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
          *    the amount of memory allocated for this scatter-gather list.
          * 3. TRBs buffers can't cross 64KB boundaries.
          */
-        sg = urb->sg->sg;
+        sg = urb->sg;
         addr = (u64) sg_dma_address(sg);
         this_sg_len = sg_dma_len(sg);
         trb_buff_len = TRB_MAX_BUFF_SIZE -
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index 8a7968df278f..e7fa3644ba6a 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -422,7 +422,7 @@ static unsigned int mon_bin_get_data(const struct mon_reader_bin *rp,
                 }
 
                 /* Copy up to the first non-addressable segment */
-                for_each_sg(urb->sg->sg, sg, urb->num_sgs, i) {
+                for_each_sg(urb->sg, sg, urb->num_sgs, i) {
                         if (length == 0 || PageHighMem(sg_page(sg)))
                                 break;
                         this_len = min_t(unsigned int, sg->length, length);
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index d56260280f54..a545d65f6e57 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -159,7 +159,7 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
                 if (src == NULL)
                         return 'Z';     /* '0' would be not as pretty. */
         } else {
-                struct scatterlist *sg = urb->sg->sg;
+                struct scatterlist *sg = urb->sg;
 
                 if (PageHighMem(sg_page(sg)))
                         return 'D';