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, 64 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/Kconfig b/drivers/usb/chipidea/Kconfig
new file mode 100644
index 000000000..bab45bc62
--- /dev/null
+++ b/drivers/usb/chipidea/Kconfig
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_CHIPIDEA
+	tristate "ChipIdea Highspeed Dual Role Controller"
+	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
+	select EXTCON
+	select RESET_CONTROLLER
+	select USB_ULPI_BUS
+	select USB_ROLE_SWITCH
+	select USB_TEGRA_PHY if ARCH_TEGRA
+	help
+	  Say Y here if your system has a dual role high speed USB
+	  controller based on ChipIdea silicon IP. It supports:
+	  Dual-role switch (ID, OTG FSM, sysfs), Host-only, and
+	  Peripheral-only.
+
+	  When compiled dynamically, the module will be called ci_hdrc.ko.
+
+if USB_CHIPIDEA
+
+config USB_CHIPIDEA_UDC
+	bool "ChipIdea device controller"
+	depends on USB_GADGET
+	help
+	  Say Y here to enable device controller functionality of the
+	  ChipIdea driver.
+
+config USB_CHIPIDEA_HOST
+	bool "ChipIdea host controller"
+	depends on USB_EHCI_HCD
+	select USB_EHCI_ROOT_HUB_TT
+	help
+	  Say Y here to enable host controller functionality of the
+	  ChipIdea driver.
+
+config USB_CHIPIDEA_PCI
+	tristate "Enable PCI glue driver" if EXPERT
+	depends on USB_PCI
+	depends on NOP_USB_XCEIV
+	default USB_CHIPIDEA
+
+config USB_CHIPIDEA_MSM
+	tristate "Enable MSM hsusb glue driver" if EXPERT
+	default USB_CHIPIDEA
+
+config USB_CHIPIDEA_NPCM
+	tristate "Enable NPCM hsusb glue driver" if EXPERT
+	default USB_CHIPIDEA
+
+config USB_CHIPIDEA_IMX
+	tristate "Enable i.MX USB glue driver" if EXPERT
+	depends on OF
+	default USB_CHIPIDEA
+
+config USB_CHIPIDEA_GENERIC
+	tristate "Enable generic USB2 glue driver" if EXPERT
+	default USB_CHIPIDEA
+
+config USB_CHIPIDEA_TEGRA
+	tristate "Enable Tegra USB glue driver" if EXPERT
+	depends on OF
+	default USB_CHIPIDEA
+
+endif