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, 29 insertions, 0 deletions

diff --git a/drivers/usb/dwc2/Makefile b/drivers/usb/dwc2/Makefile
new file mode 100644
index 000000000..2bcd6945d
--- /dev/null
+++ b/drivers/usb/dwc2/Makefile
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+ccflags-$(CONFIG_USB_DWC2_DEBUG)	+= -DDEBUG
+ccflags-$(CONFIG_USB_DWC2_VERBOSE)	+= -DVERBOSE_DEBUG
+
+obj-$(CONFIG_USB_DWC2)			+= dwc2.o
+dwc2-y					:= core.o core_intr.o platform.o drd.o
+dwc2-y					+= params.o
+
+ifneq ($(filter y,$(CONFIG_USB_DWC2_HOST) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
+	dwc2-y				+= hcd.o hcd_intr.o
+	dwc2-y				+= hcd_queue.o hcd_ddma.o
+endif
+
+ifneq ($(filter y,$(CONFIG_USB_DWC2_PERIPHERAL) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
+	dwc2-y       			+= gadget.o
+endif
+
+ifneq ($(CONFIG_DEBUG_FS),)
+	dwc2-y				+= debugfs.o
+endif
+
+# NOTE: The previous s3c-hsotg peripheral mode only driver has been moved to
+# this location and renamed gadget.c. When building for dynamically linked
+# modules, dwc2.ko will get built for host mode, peripheral mode, and dual-role
+# mode. The PCI bus interface module will called dwc2_pci.ko and the platform
+# interface module will be called dwc2_platform.ko.
+
+obj-$(CONFIG_USB_DWC2_PCI)		+= dwc2_pci.o
+dwc2_pci-y				:= pci.o