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, 19 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/Makefile b/drivers/usb/chipidea/Makefile
new file mode 100644
index 000000000..718cb2460
--- /dev/null
+++ b/drivers/usb/chipidea/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# define_trace.h needs to know how to find our header
+CFLAGS_trace.o			:= -I$(src)
+obj-$(CONFIG_USB_CHIPIDEA)		+= ci_hdrc.o
+
+ci_hdrc-y				:= core.o otg.o debug.o ulpi.o
+ci_hdrc-$(CONFIG_USB_CHIPIDEA_UDC)	+= udc.o trace.o
+ci_hdrc-$(CONFIG_USB_CHIPIDEA_HOST)	+= host.o
+ci_hdrc-$(CONFIG_USB_OTG_FSM)		+= otg_fsm.o
+
+# Glue/Bridge layers go here
+
+obj-$(CONFIG_USB_CHIPIDEA_GENERIC)	+= ci_hdrc_usb2.o
+obj-$(CONFIG_USB_CHIPIDEA_MSM)		+= ci_hdrc_msm.o
+obj-$(CONFIG_USB_CHIPIDEA_NPCM)		+= ci_hdrc_npcm.o
+obj-$(CONFIG_USB_CHIPIDEA_PCI)		+= ci_hdrc_pci.o
+obj-$(CONFIG_USB_CHIPIDEA_IMX)		+= usbmisc_imx.o ci_hdrc_imx.o
+obj-$(CONFIG_USB_CHIPIDEA_TEGRA)	+= ci_hdrc_tegra.o