usb-storage: implement "soft" unbinding
This patch (as1092) implements "soft" unbinding for usb-storage. When
the disconnect routine is called, all commands and reset delays are
allowed to complete normally until after scsi_remove_host() returns.
This means that the commands needed for an orderly shutdown will be
sent through to the device.
Unlike before, the driver will now execute every command that it
accepts. Hence there's no need for special code to catch unexecuted
commands and fail them.
The new sequence of events when disconnect runs goes as follows:
If the device is truly unplugged, set the DISCONNECTING
flag so we won't try to access it any more.
If the SCSI-scanning thread hasn't started up yet, prevent
it from doing anything by setting the new DONT_SCAN flag.
Then wake it up and wait for it to terminate.
Remove the SCSI host. This unbinds the upper-level drivers,
doing an orderly shutdown. Commands sent to quiesce the
device will be transmitted normally, unless the device is
unplugged.
Set the DISCONNECTING flag so that we won't accept any new
commands that might get submitted (there aren't supposed to be
any) and we won't try to access the device for resets.
Tell the control thread to exit by waking it up with no
pending command, and wait for it to terminate.
Go on to do all the other normal stuff: releasing resources,
freeing memory, and so on.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index 2f88bb9..94138df 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -127,8 +127,8 @@
long timeleft;
int status;
- /* don't submit URBs during abort/disconnect processing */
- if (us->dflags & ABORTING_OR_DISCONNECTING)
+ /* don't submit URBs during abort processing */
+ if (test_bit(US_FLIDX_ABORTING, &us->dflags))
return -EIO;
/* set up data structures for the wakeup system */
@@ -161,8 +161,8 @@
* to cancel it */
set_bit(US_FLIDX_URB_ACTIVE, &us->dflags);
- /* did an abort/disconnect occur during the submission? */
- if (us->dflags & ABORTING_OR_DISCONNECTING) {
+ /* did an abort occur during the submission? */
+ if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
/* cancel the URB, if it hasn't been cancelled already */
if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
@@ -419,8 +419,8 @@
{
int result;
- /* don't submit s-g requests during abort/disconnect processing */
- if (us->dflags & ABORTING_OR_DISCONNECTING)
+ /* don't submit s-g requests during abort processing */
+ if (test_bit(US_FLIDX_ABORTING, &us->dflags))
return USB_STOR_XFER_ERROR;
/* initialize the scatter-gather request block */
@@ -437,8 +437,8 @@
* okay to cancel it */
set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
- /* did an abort/disconnect occur during the submission? */
- if (us->dflags & ABORTING_OR_DISCONNECTING) {
+ /* did an abort occur during the submission? */
+ if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
/* cancel the request, if it hasn't been cancelled already */
if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {