On Tue, 15 Jun 2004, Alan Stern wrote:
> David:
>
> This patch fixes the bug you ran across in the scatter-gather library.
> (It includes my earlier change to suppress incorrect error messages as
> well).
Sorry, that patch had a mistake. It didn't take into account the
possibility that the first URB might complete before the second could be
submitted, causing io->count to reach 0 prematurely.
This patch (as316b) should do a better job. It retains the strategy of
adjusting io->count when something strange happens -- but now it does so
whenever _anything_ strange happens, rather than only when a submission
fails.
Alan Stern
P.S.: Is there some reason for that strange assignment to io->count inside
the "for" statement? I didn't see any, so I moved the assignment earlier.
Also that test for "if (io->status == -EINPROGRESS)" in usb_sg_wait()
doesn't look like it could ever succeed, so I removed it.
Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
===== drivers/usb/core/message.c 1.92 vs edited =====
--- 1.92/drivers/usb/core/message.c Fri Jun 11 07:49:33 2004
+++ edited/drivers/usb/core/message.c Wed Jun 16 09:56:54 2004
@@ -248,7 +248,7 @@
* unlink pending urbs so they won't rx/tx bad data.
*/
for (i = 0, found = 0; i < io->entries; i++) {
- if (!io->urbs [i])
+ if (!io->urbs [i] || !io->urbs [i]->dev)
continue;
if (found) {
status = usb_unlink_urb (io->urbs [i]);
@@ -337,7 +337,7 @@
if (io->entries <= 0)
return io->entries;
- io->count = 0;
+ io->count = io->entries;
io->urbs = kmalloc (io->entries * sizeof *io->urbs, mem_flags);
if (!io->urbs)
goto nomem;
@@ -347,7 +347,7 @@
if (usb_pipein (pipe))
urb_flags |= URB_SHORT_NOT_OK;
- for (i = 0; i < io->entries; i++, io->count = i) {
+ for (i = 0; i < io->entries; i++) {
unsigned len;
io->urbs [i] = usb_alloc_urb (0, mem_flags);
@@ -477,14 +477,6 @@
/* fail any uncompleted urbs */
default:
- spin_lock_irq (&io->lock);
- io->count -= entries - i;
- if (io->status == -EINPROGRESS)
- io->status = retval;
- if (io->count == 0)
- complete (&io->complete);
- spin_unlock_irq (&io->lock);
-
io->urbs [i]->dev = 0;
io->urbs [i]->status = retval;
dev_dbg (&io->dev->dev, "%s, submit --> %d\n",
@@ -495,6 +487,9 @@
if (retval && io->status == -ECONNRESET)
io->status = retval;
}
+ io->count -= entries - i;
+ if (io->count == 0)
+ complete (&io->complete);
spin_unlock_irq (&io->lock);
/* OK, yes, this could be packaged as non-blocking.
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