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, 30 insertions, 0 deletions

diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
new file mode 100644
index 000000000..6482f2bfd
--- /dev/null
+++ b/drivers/extcon/Makefile
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Makefile for external connector class (extcon) devices
+#
+
+obj-$(CONFIG_EXTCON)		+= extcon-core.o
+extcon-core-objs		+= extcon.o devres.o
+obj-$(CONFIG_EXTCON_ADC_JACK)	+= extcon-adc-jack.o
+obj-$(CONFIG_EXTCON_AXP288)	+= extcon-axp288.o
+obj-$(CONFIG_EXTCON_FSA9480)	+= extcon-fsa9480.o
+obj-$(CONFIG_EXTCON_GPIO)	+= extcon-gpio.o
+obj-$(CONFIG_EXTCON_INTEL_INT3496) += extcon-intel-int3496.o
+obj-$(CONFIG_EXTCON_INTEL_CHT_WC) += extcon-intel-cht-wc.o
+obj-$(CONFIG_EXTCON_INTEL_MRFLD) += extcon-intel-mrfld.o
+obj-$(CONFIG_EXTCON_LC824206XA)	+= extcon-lc824206xa.o
+obj-$(CONFIG_EXTCON_MAX14577)	+= extcon-max14577.o
+obj-$(CONFIG_EXTCON_MAX3355)	+= extcon-max3355.o
+obj-$(CONFIG_EXTCON_MAX77693)	+= extcon-max77693.o
+obj-$(CONFIG_EXTCON_MAX77843)	+= extcon-max77843.o
+obj-$(CONFIG_EXTCON_MAX8997)	+= extcon-max8997.o
+obj-$(CONFIG_EXTCON_MAX14526)	+= extcon-max14526.o
+obj-$(CONFIG_EXTCON_PALMAS)	+= extcon-palmas.o
+obj-$(CONFIG_EXTCON_PTN5150)	+= extcon-ptn5150.o
+obj-$(CONFIG_EXTCON_QCOM_SPMI_MISC) += extcon-qcom-spmi-misc.o
+obj-$(CONFIG_EXTCON_RT8973A)	+= extcon-rt8973a.o
+obj-$(CONFIG_EXTCON_SM5502)	+= extcon-sm5502.o
+obj-$(CONFIG_EXTCON_USB_GPIO)	+= extcon-usb-gpio.o
+obj-$(CONFIG_EXTCON_USBC_CROS_EC) += extcon-usbc-cros-ec.o
+obj-$(CONFIG_EXTCON_USBC_TUSB320) += extcon-usbc-tusb320.o
+obj-$(CONFIG_EXTCON_RTK_TYPE_C) += extcon-rtk-type-c.o