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author | Alan Stern <stern@rowland.harvard.edu> | 2013-03-22 13:30:56 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-25 13:35:05 -0700 |
commit | 79bcf7b02ba3d45bafe81a2753cedb8ef49548e3 (patch) | |
tree | da06b30b0fdd12dfb3286bed6a940bd2e4e0dfe0 /drivers/usb/host/ehci-q.c | |
parent | c1fdb68e3d73741630ca16695cf9176c233be7ed (diff) | |
download | op-kernel-dev-79bcf7b02ba3d45bafe81a2753cedb8ef49548e3.zip op-kernel-dev-79bcf7b02ba3d45bafe81a2753cedb8ef49548e3.tar.gz |
USB: EHCI: change return value of qh_completions()
This patch (as1658) cleans up the usage of qh_completions() in
ehci-hcd. Currently the function's return value indicates whether any
URBs were given back; the idea was that the caller can scan the QH
over again to handle any URBs that were dequeued by a completion
handler. This is not necessary; when qh_completions() is ready to
give back dequeued URBs, it does its own rescanning.
Therefore the new return value will be a flag indicating whether the
caller needs to unlink the QH. This is more convenient than forcing
the caller to check qh->needs_rescan, and it makes a lot more sense --
why should "needs_rescan" imply that an unlink is needed? The callers
are also changed to remove the unneeded rescans.
Lastly, the check for whether qh->qtd_list is non-empty is removed
from the start of qh_completions(). Two of the callers have to make
this test anyway, so the same test can simply be added to the other
two callers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
-rw-r--r-- | drivers/usb/host/ehci-q.c | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index b824cb6..c95f60d 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -292,8 +292,8 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh); /* * Process and free completed qtds for a qh, returning URBs to drivers. - * Chases up to qh->hw_current. Returns number of completions called, - * indicating how much "real" work we did. + * Chases up to qh->hw_current. Returns nonzero if the caller should + * unlink qh. */ static unsigned qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh) @@ -302,13 +302,9 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh) struct list_head *entry, *tmp; int last_status; int stopped; - unsigned count = 0; u8 state; struct ehci_qh_hw *hw = qh->hw; - if (unlikely (list_empty (&qh->qtd_list))) - return count; - /* completions (or tasks on other cpus) must never clobber HALT * till we've gone through and cleaned everything up, even when * they add urbs to this qh's queue or mark them for unlinking. @@ -345,7 +341,6 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh) if (last) { if (likely (last->urb != urb)) { ehci_urb_done(ehci, last->urb, last_status); - count++; last_status = -EINPROGRESS; } ehci_qtd_free (ehci, last); @@ -519,7 +514,6 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh) /* last urb's completion might still need calling */ if (likely (last != NULL)) { ehci_urb_done(ehci, last->urb, last_status); - count++; ehci_qtd_free (ehci, last); } @@ -566,7 +560,7 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh) /* otherwise, unlink already started */ } - return count; + return qh->needs_rescan; } /*-------------------------------------------------------------------------*/ @@ -1254,7 +1248,8 @@ static void end_unlink_async(struct ehci_hcd *ehci) qh->qh_state = QH_STATE_IDLE; qh->qh_next.qh = NULL; - qh_completions(ehci, qh); + if (!list_empty(&qh->qtd_list)) + qh_completions(ehci, qh); if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) qh_link_async(ehci, qh); @@ -1348,7 +1343,7 @@ static void scan_async (struct ehci_hcd *ehci) while (ehci->qh_scan_next) { qh = ehci->qh_scan_next; ehci->qh_scan_next = qh->qh_next.qh; - rescan: + /* clean any finished work for this qh */ if (!list_empty(&qh->qtd_list)) { int temp; @@ -1361,14 +1356,13 @@ static void scan_async (struct ehci_hcd *ehci) * in single_unlink_async(). */ temp = qh_completions(ehci, qh); - if (qh->needs_rescan) { + if (unlikely(temp)) { start_unlink_async(ehci, qh); } else if (list_empty(&qh->qtd_list) && qh->qh_state == QH_STATE_LINKED) { qh->unlink_cycle = ehci->async_unlink_cycle; check_unlinks_later = true; - } else if (temp != 0) - goto rescan; + } } } |