<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/usb/storage, branch linux-3.18.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>USB: core: Fix bug caused by duplicate interface PM usage counter</title>
<updated>2019-05-16T07:17:18+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2019-04-19T17:52:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bc1c5d1ac4772cbc39e485ee94bdf2e9d8a2cd7d'/>
<id>bc1c5d1ac4772cbc39e485ee94bdf2e9d8a2cd7d</id>
<content type='text'>
commit c2b71462d294cf517a0bc6e4fd6424d7cee5596f upstream.

The syzkaller fuzzer reported a bug in the USB hub driver which turned
out to be caused by a negative runtime-PM usage counter.  This allowed
a hub to be runtime suspended at a time when the driver did not expect
it.  The symptom is a WARNING issued because the hub's status URB is
submitted while it is already active:

	URB 0000000031fb463e submitted while active
	WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363

The negative runtime-PM usage count was caused by an unfortunate
design decision made when runtime PM was first implemented for USB.
At that time, USB class drivers were allowed to unbind from their
interfaces without balancing the usage counter (i.e., leaving it with
a positive count).  The core code would take care of setting the
counter back to 0 before allowing another driver to bind to the
interface.

Later on when runtime PM was implemented for the entire kernel, the
opposite decision was made: Drivers were required to balance their
runtime-PM get and put calls.  In order to maintain backward
compatibility, however, the USB subsystem adapted to the new
implementation by keeping an independent usage counter for each
interface and using it to automatically adjust the normal usage
counter back to 0 whenever a driver was unbound.

This approach involves duplicating information, but what is worse, it
doesn't work properly in cases where a USB class driver delays
decrementing the usage counter until after the driver's disconnect()
routine has returned and the counter has been adjusted back to 0.
Doing so would cause the usage counter to become negative.  There's
even a warning about this in the USB power management documentation!

As it happens, this is exactly what the hub driver does.  The
kick_hub_wq() routine increments the runtime-PM usage counter, and the
corresponding decrement is carried out by hub_event() in the context
of the hub_wq work-queue thread.  This work routine may sometimes run
after the driver has been unbound from its interface, and when it does
it causes the usage counter to go negative.

It is not possible for hub_disconnect() to wait for a pending
hub_event() call to finish, because hub_disconnect() is called with
the device lock held and hub_event() acquires that lock.  The only
feasible fix is to reverse the original design decision: remove the
duplicate interface-specific usage counter and require USB drivers to
balance their runtime PM gets and puts.  As far as I know, all
existing drivers currently do this.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com
CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c2b71462d294cf517a0bc6e4fd6424d7cee5596f upstream.

The syzkaller fuzzer reported a bug in the USB hub driver which turned
out to be caused by a negative runtime-PM usage counter.  This allowed
a hub to be runtime suspended at a time when the driver did not expect
it.  The symptom is a WARNING issued because the hub's status URB is
submitted while it is already active:

	URB 0000000031fb463e submitted while active
	WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363

The negative runtime-PM usage count was caused by an unfortunate
design decision made when runtime PM was first implemented for USB.
At that time, USB class drivers were allowed to unbind from their
interfaces without balancing the usage counter (i.e., leaving it with
a positive count).  The core code would take care of setting the
counter back to 0 before allowing another driver to bind to the
interface.

Later on when runtime PM was implemented for the entire kernel, the
opposite decision was made: Drivers were required to balance their
runtime-PM get and put calls.  In order to maintain backward
compatibility, however, the USB subsystem adapted to the new
implementation by keeping an independent usage counter for each
interface and using it to automatically adjust the normal usage
counter back to 0 whenever a driver was unbound.

This approach involves duplicating information, but what is worse, it
doesn't work properly in cases where a USB class driver delays
decrementing the usage counter until after the driver's disconnect()
routine has returned and the counter has been adjusted back to 0.
Doing so would cause the usage counter to become negative.  There's
even a warning about this in the USB power management documentation!

As it happens, this is exactly what the hub driver does.  The
kick_hub_wq() routine increments the runtime-PM usage counter, and the
corresponding decrement is carried out by hub_event() in the context
of the hub_wq work-queue thread.  This work routine may sometimes run
after the driver has been unbound from its interface, and when it does
it causes the usage counter to go negative.

It is not possible for hub_disconnect() to wait for a pending
hub_event() call to finish, because hub_disconnect() is called with
the device lock held and hub_event() acquires that lock.  The only
feasible fix is to reverse the original design decision: remove the
duplicate interface-specific usage counter and require USB drivers to
balance their runtime PM gets and puts.  As far as I know, all
existing drivers currently do this.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com
CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: storage: add quirk for SMI SM3350</title>
<updated>2019-01-26T08:44:24+00:00</updated>
<author>
<name>Icenowy Zheng</name>
<email>icenowy@aosc.io</email>
</author>
<published>2019-01-03T03:26:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=84fe5c6e95e6469d7d3360b6d0fa03f13dc41200'/>
<id>84fe5c6e95e6469d7d3360b6d0fa03f13dc41200</id>
<content type='text'>
commit 0a99cc4b8ee83885ab9f097a3737d1ab28455ac0 upstream.

The SMI SM3350 USB-UFS bridge controller cannot handle long sense request
correctly and will make the chip refuse to do read/write when requested
long sense.

Add a bad sense quirk for it.

Signed-off-by: Icenowy Zheng &lt;icenowy@aosc.io&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0a99cc4b8ee83885ab9f097a3737d1ab28455ac0 upstream.

The SMI SM3350 USB-UFS bridge controller cannot handle long sense request
correctly and will make the chip refuse to do read/write when requested
long sense.

Add a bad sense quirk for it.

Signed-off-by: Icenowy Zheng &lt;icenowy@aosc.io&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: storage: don't insert sane sense for SPC3+ when bad sense specified</title>
<updated>2019-01-26T08:44:24+00:00</updated>
<author>
<name>Icenowy Zheng</name>
<email>icenowy@aosc.io</email>
</author>
<published>2019-01-03T03:26:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5a2cac02dc5d4a2633498620c22f3054248dc66c'/>
<id>5a2cac02dc5d4a2633498620c22f3054248dc66c</id>
<content type='text'>
commit c5603d2fdb424849360fe7e3f8c1befc97571b8c upstream.

Currently the code will set US_FL_SANE_SENSE flag unconditionally if
device claims SPC3+, however we should allow US_FL_BAD_SENSE flag to
prevent this behavior, because SMI SM3350 UFS-USB bridge controller,
which claims SPC4, will show strange behavior with 96-byte sense
(put the chip into a wrong state that cannot read/write anything).

Check the presence of US_FL_BAD_SENSE when assuming US_FL_SANE_SENSE on
SPC4+ devices.

Signed-off-by: Icenowy Zheng &lt;icenowy@aosc.io&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c5603d2fdb424849360fe7e3f8c1befc97571b8c upstream.

Currently the code will set US_FL_SANE_SENSE flag unconditionally if
device claims SPC3+, however we should allow US_FL_BAD_SENSE flag to
prevent this behavior, because SMI SM3350 UFS-USB bridge controller,
which claims SPC4, will show strange behavior with 96-byte sense
(put the chip into a wrong state that cannot read/write anything).

Check the presence of US_FL_BAD_SENSE when assuming US_FL_SANE_SENSE on
SPC4+ devices.

Signed-off-by: Icenowy Zheng &lt;icenowy@aosc.io&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: usb-storage: Add new IDs to ums-realtek</title>
<updated>2018-12-13T08:22:28+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2018-11-23T08:42:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=591c2660ef2b1892352dda22bcc18880855ab23e'/>
<id>591c2660ef2b1892352dda22bcc18880855ab23e</id>
<content type='text'>
commit a84a1bcc992f0545a51d2e120b8ca2ef20e2ea97 upstream.

There are two new Realtek card readers require ums-realtek to work
correctly.

Add the new IDs to support them.

Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a84a1bcc992f0545a51d2e120b8ca2ef20e2ea97 upstream.

There are two new Realtek card readers require ums-realtek to work
correctly.

Add the new IDs to support them.

Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>uas: disable UAS on Apricorn SATA dongles</title>
<updated>2018-11-10T15:39:15+00:00</updated>
<author>
<name>Darrick J. Wong</name>
<email>darrick.wong@oracle.com</email>
</author>
<published>2014-12-11T19:01:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c17101a61e54beb2b7fcc0090360871ffaf03684'/>
<id>c17101a61e54beb2b7fcc0090360871ffaf03684</id>
<content type='text'>
[ Upstream commit 36d1ffdb210ec2d0d6a69e9f6466ae8727d34119 ]

The Apricorn SATA dongle will occasionally return "USBSUSBSUSB" in
response to SCSI commands when running in UAS mode.  Therefore,
disable UAS mode on this dongle.

Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Acked-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 36d1ffdb210ec2d0d6a69e9f6466ae8727d34119 ]

The Apricorn SATA dongle will occasionally return "USBSUSBSUSB" in
response to SCSI commands when running in UAS mode.  Therefore,
disable UAS mode on this dongle.

Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Acked-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Add quirk to support DJI CineSSD</title>
<updated>2018-09-26T06:33:57+00:00</updated>
<author>
<name>Tim Anderson</name>
<email>tsa@biglakesoftware.com</email>
</author>
<published>2018-08-09T21:55:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fbc35884e1cadd0da82e5ff8a95235964bc1ca93'/>
<id>fbc35884e1cadd0da82e5ff8a95235964bc1ca93</id>
<content type='text'>
commit f45681f9becaa65111ed0a691ccf080a0cd5feb8 upstream.

This device does not correctly handle the LPM operations.

Also, the device cannot handle ATA pass-through commands
and locks up when attempted while running in super speed.

This patch adds the equivalent quirk logic as found in uas.

Signed-off-by: Tim Anderson &lt;tsa@biglakesoftware.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f45681f9becaa65111ed0a691ccf080a0cd5feb8 upstream.

This device does not correctly handle the LPM operations.

Also, the device cannot handle ATA pass-through commands
and locks up when attempted while running in super speed.

This patch adds the equivalent quirk logic as found in uas.

Signed-off-by: Tim Anderson &lt;tsa@biglakesoftware.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: ene_usb6250: fix SCSI residue overwriting</title>
<updated>2018-04-13T17:52:13+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2017-05-16T15:47:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=13ab5f87781bd606daf56e9bd72fe43d080f3c4c'/>
<id>13ab5f87781bd606daf56e9bd72fe43d080f3c4c</id>
<content type='text'>
[ Upstream commit aa18c4b6e0e39bfb00af48734ec24bc189ac9909 ]

In the ene_usb6250 sub-driver for usb-storage, the SCSI residue is not
reported correctly.  The residue is initialized to 0, but this value
is overwritten whenever the driver sends firmware to the card reader
before performing the current command.  As a result, a valid READ or
WRITE operation appears to have failed, causing the SCSI core to retry
the command multiple times and eventually fail.

This patch fixes the problem by resetting the SCSI residue to 0 after
sending firmware to the device.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: Andreas Hartmann &lt;andihartmann@01019freenet.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit aa18c4b6e0e39bfb00af48734ec24bc189ac9909 ]

In the ene_usb6250 sub-driver for usb-storage, the SCSI residue is not
reported correctly.  The residue is initialized to 0, but this value
is overwritten whenever the driver sends firmware to the card reader
before performing the current command.  As a result, a valid READ or
WRITE operation appears to have failed, causing the SCSI core to retry
the command multiple times and eventually fail.

This patch fixes the problem by resetting the SCSI residue to 0 after
sending firmware to the device.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: Andreas Hartmann &lt;andihartmann@01019freenet.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: ene_usb6250: fix first command execution</title>
<updated>2018-04-13T17:52:13+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2017-05-16T15:47:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=17805e4b848097e1ee4672cfbfaeb6a7bcacac5c'/>
<id>17805e4b848097e1ee4672cfbfaeb6a7bcacac5c</id>
<content type='text'>
[ Upstream commit 4b309f1c4972c8f09e03ac64fc63510dbf5591a4 ]

In the ene_usb6250 sub-driver for usb-storage, the ene_transport()
routine is supposed to initialize the driver before executing the
current command, if the initialization has not already been performed.
However, a bug in the routine causes it to skip the command after
doing the initialization.  Also, the routine does not return an
appropriate error code if either the initialization or the command
fails.

As a result of the first bug, the first command (a SCSI INQUIRY) is
not carried out.  The results can be seen in the system log, in the
form of a warning message and empty or garbage INQUIRY data:

Apr 18 22:40:08 notebook2 kernel: scsi host6: scsi scan: INQUIRY result too short (5), using 36
Apr 18 22:40:08 notebook2 kernel: scsi 6:0:0:0: Direct-Access                                    PQ: 0 ANSI: 0

This patch fixes both errors.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: Andreas Hartmann &lt;andihartmann@01019freenet.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4b309f1c4972c8f09e03ac64fc63510dbf5591a4 ]

In the ene_usb6250 sub-driver for usb-storage, the ene_transport()
routine is supposed to initialize the driver before executing the
current command, if the initialization has not already been performed.
However, a bug in the routine causes it to skip the command after
doing the initialization.  Also, the routine does not return an
appropriate error code if either the initialization or the command
fails.

As a result of the first bug, the first command (a SCSI INQUIRY) is
not carried out.  The results can be seen in the system log, in the
form of a warning message and empty or garbage INQUIRY data:

Apr 18 22:40:08 notebook2 kernel: scsi host6: scsi scan: INQUIRY result too short (5), using 36
Apr 18 22:40:08 notebook2 kernel: scsi 6:0:0:0: Direct-Access                                    PQ: 0 ANSI: 0

This patch fixes both errors.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: Andreas Hartmann &lt;andihartmann@01019freenet.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>uas: fix comparison for error code</title>
<updated>2018-03-18T10:15:44+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2018-03-06T14:04:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8d5ac33dba6b5a01163b3a722bb0ee58448476a8'/>
<id>8d5ac33dba6b5a01163b3a722bb0ee58448476a8</id>
<content type='text'>
commit 9a513c905bb95bef79d96feb08621c1ec8d8c4bb upstream.

A typo broke the comparison.

Fixes: cbeef22fd611 ("usb: uas: unconditionally bring back host after reset")
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
CC: stable@kernel.org
Acked-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 9a513c905bb95bef79d96feb08621c1ec8d8c4bb upstream.

A typo broke the comparison.

Fixes: cbeef22fd611 ("usb: uas: unconditionally bring back host after reset")
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
CC: stable@kernel.org
Acked-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>usb: uas: unconditionally bring back host after reset</title>
<updated>2018-02-07T19:07:57+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2018-01-11T12:10:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fc6fd81a9e56b38cac9c37d557331c28daba1f4b'/>
<id>fc6fd81a9e56b38cac9c37d557331c28daba1f4b</id>
<content type='text'>
commit cbeef22fd611c4f47c494b821b2b105b8af970bb upstream.

Quoting Hans:

If we return 1 from our post_reset handler, then our disconnect handler
will be called immediately afterwards. Since pre_reset blocks all scsi
requests our disconnect handler will then hang in the scsi_remove_host
call.

This is esp. bad because our disconnect handler hanging for ever also
stops the USB subsys from enumerating any new USB devices, causes commands
like lsusb to hang, etc.

In practice this happens when unplugging some uas devices because the hub
code may see the device as needing a warm-reset and calls usb_reset_device
before seeing the disconnect. In this case uas_configure_endpoints fails
with -ENODEV. We do not want to print an error for this, so this commit
also silences the shost_printk for -ENODEV.

ENDQUOTE

However, if we do that we better drop any unconditional execution
and report to the SCSI subsystem that we have undergone a reset
but we are not operational now.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Reported-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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<pre>
commit cbeef22fd611c4f47c494b821b2b105b8af970bb upstream.

Quoting Hans:

If we return 1 from our post_reset handler, then our disconnect handler
will be called immediately afterwards. Since pre_reset blocks all scsi
requests our disconnect handler will then hang in the scsi_remove_host
call.

This is esp. bad because our disconnect handler hanging for ever also
stops the USB subsys from enumerating any new USB devices, causes commands
like lsusb to hang, etc.

In practice this happens when unplugging some uas devices because the hub
code may see the device as needing a warm-reset and calls usb_reset_device
before seeing the disconnect. In this case uas_configure_endpoints fails
with -ENODEV. We do not want to print an error for this, so this commit
also silences the shost_printk for -ENODEV.

ENDQUOTE

However, if we do that we better drop any unconditional execution
and report to the SCSI subsystem that we have undergone a reset
but we are not operational now.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Reported-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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