USB: reorganize urb->status use in ehci-hcd

This patch (as974) reorganizes the way ehci-hcd sets urb->status.  It
now keeps the information in a local variable until the last moment.

The patch also simplifies the handling of -EREMOTEIO, since the only
use of that code is to set the do_status flag.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index a8f5408c161d691d192a3bf63e4b8ee3cc060cab..794d27e07807ce17983ed582430eb042e6b14a05 100644 (file)
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -139,63 +139,65 @@ qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
 
 /*-------------------------------------------------------------------------*/
 
-static void qtd_copy_status (
+static int qtd_copy_status (
        struct ehci_hcd *ehci,
        struct urb *urb,
        size_t length,
        u32 token
 )
 {
+       int     status = -EINPROGRESS;
+
        /* count IN/OUT bytes, not SETUP (even short packets) */
        if (likely (QTD_PID (token) != 2))
                urb->actual_length += length - QTD_LENGTH (token);
 
        /* don't modify error codes */
        if (unlikely(urb->unlinked))
-               return;
+               return status;
 
        /* force cleanup after short read; not always an error */
        if (unlikely (IS_SHORT_READ (token)))
-               urb->status = -EREMOTEIO;
+               status = -EREMOTEIO;
 
        /* serious "can't proceed" faults reported by the hardware */
        if (token & QTD_STS_HALT) {
                if (token & QTD_STS_BABBLE) {
                        /* FIXME "must" disable babbling device's port too */
-                       urb->status = -EOVERFLOW;
+                       status = -EOVERFLOW;
                } else if (token & QTD_STS_MMF) {
                        /* fs/ls interrupt xfer missed the complete-split */
-                       urb->status = -EPROTO;
+                       status = -EPROTO;
                } else if (token & QTD_STS_DBE) {
-                       urb->status = (QTD_PID (token) == 1) /* IN ? */
+                       status = (QTD_PID (token) == 1) /* IN ? */
                                ? -ENOSR  /* hc couldn't read data */
                                : -ECOMM; /* hc couldn't write data */
                } else if (token & QTD_STS_XACT) {
                        /* timeout, bad crc, wrong PID, etc; retried */
                        if (QTD_CERR (token))
-                               urb->status = -EPIPE;
+                               status = -EPIPE;
                        else {
                                ehci_dbg (ehci, "devpath %s ep%d%s 3strikes\n",
                                        urb->dev->devpath,
                                        usb_pipeendpoint (urb->pipe),
                                        usb_pipein (urb->pipe) ? "in" : "out");
-                               urb->status = -EPROTO;
+                               status = -EPROTO;
                        }
                /* CERR nonzero + no errors + halt --> stall */
                } else if (QTD_CERR (token))
-                       urb->status = -EPIPE;
+                       status = -EPIPE;
                else    /* unknown */
-                       urb->status = -EPROTO;
+                       status = -EPROTO;
 
                ehci_vdbg (ehci,
                        "dev%d ep%d%s qtd token %08x --> status %d\n",
                        usb_pipedevice (urb->pipe),
                        usb_pipeendpoint (urb->pipe),
                        usb_pipein (urb->pipe) ? "in" : "out",
-                       token, urb->status);
+                       token, status);
 
                /* if async CSPLIT failed, try cleaning out the TT buffer */
-               if (urb->status != -EPIPE
+               if (status != -EPIPE
                                && urb->dev->tt && !usb_pipeint (urb->pipe)
                                && ((token & QTD_STS_MMF) != 0
                                        || QTD_CERR(token) == 0)
@@ -212,10 +214,12 @@ static void qtd_copy_status (
                        usb_hub_tt_clear_buffer (urb->dev, urb->pipe);
                }
        }
+
+       return status;
 }
 
 static void
-ehci_urb_done (struct ehci_hcd *ehci, struct urb *urb)
+ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status)
 __releases(ehci->lock)
 __acquires(ehci->lock)
 {
@@ -231,17 +235,13 @@ __acquires(ehci->lock)
                qh_put (qh);
        }
 
-       spin_lock (&urb->lock);
        if (unlikely(urb->unlinked)) {
                COUNT(ehci->stats.unlink);
        } else {
-               if (likely(urb->status == -EINPROGRESS ||
-                               (urb->status == -EREMOTEIO &&
-                                !(urb->transfer_flags & URB_SHORT_NOT_OK))))
-                       urb->status = 0;
+               if (likely(status == -EINPROGRESS))
+                       status = 0;
                COUNT(ehci->stats.complete);
        }
-       spin_unlock (&urb->lock);
 
 #ifdef EHCI_URB_TRACE
        ehci_dbg (ehci,
@@ -249,13 +249,14 @@ __acquires(ehci->lock)
                __FUNCTION__, urb->dev->devpath, urb,
                usb_pipeendpoint (urb->pipe),
                usb_pipein (urb->pipe) ? "in" : "out",
-               urb->status,
+               status,
                urb->actual_length, urb->transfer_buffer_length);
 #endif
 
        /* complete() can reenter this HCD */
        usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
        spin_unlock (&ehci->lock);
+       urb->status = status;
        usb_hcd_giveback_urb (ehci_to_hcd(ehci), urb);
        spin_lock (&ehci->lock);
 }
@@ -276,6 +277,7 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
        struct ehci_qtd         *last = NULL, *end = qh->dummy;
        struct list_head        *entry, *tmp;
+       int                     last_status = -EINPROGRESS;
        int                     stopped;
        unsigned                count = 0;
        int                     do_status = 0;
@@ -304,6 +306,7 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
                struct ehci_qtd *qtd;
                struct urb      *urb;
                u32             token = 0;
+               int             qtd_status;
 
                qtd = list_entry (entry, struct ehci_qtd, qtd_list);
                urb = qtd->urb;
@@ -311,11 +314,12 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
                /* clean up any state from previous QTD ...*/
                if (last) {
                        if (likely (last->urb != urb)) {
-                               ehci_urb_done (ehci, last->urb);
+                               ehci_urb_done(ehci, last->urb, last_status);
                                count++;
                        }
                        ehci_qtd_free (ehci, last);
                        last = NULL;
+                       last_status = -EINPROGRESS;
                }
 
                /* ignore urbs submitted during completions we reported */
@@ -351,13 +355,13 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
                        stopped = 1;
 
                        if (unlikely (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)))
-                               urb->status = -ESHUTDOWN;
+                               last_status = -ESHUTDOWN;
 
                        /* ignore active urbs unless some previous qtd
                         * for the urb faulted (including short read) or
                         * its urb was canceled.  we may patch qh or qtds.
                         */
-                       if (likely(urb->status == -EINPROGRESS &&
+                       if (likely(last_status == -EINPROGRESS &&
                                        !urb->unlinked))
                                continue;
 
@@ -386,14 +390,14 @@ halt:
                }
 
                /* remove it from the queue */
-               spin_lock (&urb->lock);
-               qtd_copy_status (ehci, urb, qtd->length, token);
-               if (unlikely(urb->status == -EREMOTEIO)) {
+               qtd_status = qtd_copy_status(ehci, urb, qtd->length, token);
+               if (unlikely(qtd_status == -EREMOTEIO)) {
                        do_status = (!urb->unlinked &&
                                        usb_pipecontrol(urb->pipe));
-                       urb->status = 0;
+                       qtd_status = 0;
                }
-               spin_unlock (&urb->lock);
+               if (likely(last_status == -EINPROGRESS))
+                       last_status = qtd_status;
 
                if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
                        last = list_entry (qtd->qtd_list.prev,
@@ -406,7 +410,7 @@ halt:
 
        /* last urb's completion might still need calling */
        if (likely (last != NULL)) {
-               ehci_urb_done (ehci, last->urb);
+               ehci_urb_done(ehci, last->urb, last_status);
                count++;
                ehci_qtd_free (ehci, last);
        }

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 8b267b3fd2bb42bda70f6a0ece65c13af7db192e..80d99bce2b38fb3d5a6459cdff8eeb5642fa0b06 100644 (file)
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1627,7 +1627,7 @@ itd_complete (
 
        /* give urb back to the driver ... can be out-of-order */
        dev = urb->dev;
-       ehci_urb_done (ehci, urb);
+       ehci_urb_done(ehci, urb, 0);
        urb = NULL;
 
        /* defer stopping schedule; completion can submit */
@@ -2000,7 +2000,7 @@ sitd_complete (
 
        /* give urb back to the driver */
        dev = urb->dev;
-       ehci_urb_done (ehci, urb);
+       ehci_urb_done(ehci, urb, 0);
        urb = NULL;
 
        /* defer stopping schedule; completion can submit */