USB: simplify usb_sg_init()
This patch (as1377) simplifies the code in usb_sg_init(), without
changing its functionality. It also removes a couple of unused fields
from the usb_sg_request structure.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 63919b8..a73e08f 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -371,79 +371,64 @@
spin_lock_init(&io->lock);
io->dev = dev;
io->pipe = pipe;
- io->sg = sg;
- io->nents = nents;
- io->entries = nents;
+
+ if (dev->bus->sg_tablesize > 0) {
+ use_sg = true;
+ io->entries = 1;
+ } else {
+ use_sg = false;
+ io->entries = nents;
+ }
/* initialize all the urbs we'll use */
- if (dev->bus->sg_tablesize > 0) {
- io->urbs = kmalloc(sizeof *io->urbs, mem_flags);
- use_sg = true;
- } else {
- io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags);
- use_sg = false;
- }
+ io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags);
if (!io->urbs)
goto nomem;
- urb_flags = 0;
+ urb_flags = URB_NO_INTERRUPT;
if (usb_pipein(pipe))
urb_flags |= URB_SHORT_NOT_OK;
- if (use_sg) {
- io->urbs[0] = usb_alloc_urb(0, mem_flags);
- if (!io->urbs[0]) {
- io->entries = 0;
+ for_each_sg(sg, sg, io->entries, i) {
+ struct urb *urb;
+ unsigned len;
+
+ urb = usb_alloc_urb(0, mem_flags);
+ if (!urb) {
+ io->entries = i;
goto nomem;
}
+ io->urbs[i] = urb;
- io->urbs[0]->dev = NULL;
- io->urbs[0]->pipe = pipe;
- io->urbs[0]->interval = period;
- io->urbs[0]->transfer_flags = urb_flags;
+ urb->dev = NULL;
+ urb->pipe = pipe;
+ urb->interval = period;
+ urb->transfer_flags = urb_flags;
+ urb->complete = sg_complete;
+ urb->context = io;
+ urb->sg = sg;
- io->urbs[0]->complete = sg_complete;
- io->urbs[0]->context = io;
+ if (use_sg) {
+ /* There is no single transfer buffer */
+ urb->transfer_buffer = NULL;
+ urb->num_sgs = nents;
- /* A length of zero means transfer the whole sg list */
- io->urbs[0]->transfer_buffer_length = length;
- if (length == 0) {
- for_each_sg(sg, sg, io->entries, i) {
- io->urbs[0]->transfer_buffer_length +=
- sg->length;
+ /* A length of zero means transfer the whole sg list */
+ len = length;
+ if (len == 0) {
+ for_each_sg(sg, sg, nents, i)
+ len += sg->length;
}
- }
- io->urbs[0]->sg = sg;
- io->urbs[0]->num_sgs = io->entries;
- io->entries = 1;
- } else {
- urb_flags |= URB_NO_INTERRUPT;
- for_each_sg(sg, sg, io->entries, i) {
- unsigned len;
-
- io->urbs[i] = usb_alloc_urb(0, mem_flags);
- if (!io->urbs[i]) {
- io->entries = i;
- goto nomem;
- }
-
- io->urbs[i]->dev = NULL;
- io->urbs[i]->pipe = pipe;
- io->urbs[i]->interval = period;
- io->urbs[i]->transfer_flags = urb_flags;
-
- io->urbs[i]->complete = sg_complete;
- io->urbs[i]->context = io;
-
+ } else {
/*
* Some systems can't use DMA; they use PIO instead.
* For their sakes, transfer_buffer is set whenever
* possible.
*/
if (!PageHighMem(sg_page(sg)))
- io->urbs[i]->transfer_buffer = sg_virt(sg);
+ urb->transfer_buffer = sg_virt(sg);
else
- io->urbs[i]->transfer_buffer = NULL;
+ urb->transfer_buffer = NULL;
len = sg->length;
if (length) {
@@ -452,12 +437,10 @@
if (length == 0)
io->entries = i + 1;
}
- io->urbs[i]->transfer_buffer_length = len;
-
- io->urbs[i]->sg = sg;
}
- io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
+ urb->transfer_buffer_length = len;
}
+ io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
/* transaction state */
io->count = io->entries;
diff --git a/include/linux/usb.h b/include/linux/usb.h
index eec9e74..ce07062 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1469,8 +1469,6 @@
struct usb_device *dev;
int pipe;
- struct scatterlist *sg;
- int nents;
int entries;
struct urb **urbs;
