netfs: zero the tail of a short DIO/unbuffered readgrafted

The buffered read collector zero-fills the tail of a short read that
stops below the inode's i_size (netfs_clear_unread()), so a read that
races an extending write still returns the expected number of bytes.
The non-buffered collector path does no such thing: it just records
how much was transferred.

Add the same zero-fill for the non-buffered case, gated on
NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short
result from it is known to be safe to treat as a hole, as opposed to
NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of
the file and should be reported short as-is. Only CLEAR_TAIL should
zero-fill here; a real EOF must stay a real short read.

No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest,
so this is inert on its own -- a following change teaches cifs to set
it in the one case that needs it.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

1 files changed, 51 insertions, 0 deletions

diff --git a/drivers/usb/common/Kconfig b/drivers/usb/common/Kconfig
new file mode 100644
index 000000000..b85662243
--- /dev/null
+++ b/drivers/usb/common/Kconfig
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_COMMON
+	tristate
+
+
+config USB_LED_TRIG
+	bool "USB LED Triggers"
+	depends on LEDS_CLASS && USB_COMMON && LEDS_TRIGGERS
+	help
+	  This option adds LED triggers for USB host and/or gadget activity.
+
+	  Say Y here if you are working on a system with led-class supported
+	  LEDs and you want to use them as activity indicators for USB host or
+	  gadget.
+
+config USB_ULPI_BUS
+	tristate "USB ULPI PHY interface support"
+	select USB_COMMON
+	help
+	  UTMI+ Low Pin Interface (ULPI) is specification for a commonly used
+	  USB 2.0 PHY interface. The ULPI specification defines a standard set
+	  of registers that can be used to detect the vendor and product which
+	  allows ULPI to be handled as a bus. This module is the driver for that
+	  bus.
+
+	  The ULPI interfaces (the buses) are registered by the drivers for USB
+	  controllers which support ULPI register access and have ULPI PHY
+	  attached to them. The ULPI PHY drivers themselves are normal PHY
+	  drivers.
+
+	  ULPI PHYs provide often functions such as ADP sensing/probing (OTG
+	  protocol) and USB charger detection.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called ulpi.
+
+config USB_CONN_GPIO
+	tristate "USB GPIO Based Connection Detection Driver"
+	depends on GPIOLIB
+	select USB_ROLE_SWITCH
+	select POWER_SUPPLY
+	help
+	  The driver supports USB role switch between host and device via GPIO
+	  based USB cable detection, used typically if an input GPIO is used
+	  to detect USB ID pin, and another input GPIO may be also used to detect
+	  Vbus pin at the same time, it also can be used to enable/disable
+	  device if an input GPIO is only used to detect Vbus pin.
+
+	  To compile the driver as a module, choose M here: the module will
+	  be called usb-conn-gpio.ko