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, 136 insertions, 0 deletions

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
new file mode 100644
index 000000000..d1b0affb8
--- /dev/null
+++ b/drivers/acpi/Makefile
@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux ACPI interpreter
+#
+
+ccflags-$(CONFIG_ACPI_DEBUG)	+= -DACPI_DEBUG_OUTPUT
+
+ifdef CONFIG_TRACE_BRANCH_PROFILING
+CFLAGS_processor_idle.o += -DDISABLE_BRANCH_PROFILING
+endif
+
+#
+# ACPI Boot-Time Table Parsing
+#
+ifeq ($(CONFIG_ACPI_CUSTOM_DSDT),y)
+tables.o: $(src)/../../include/$(CONFIG_ACPI_CUSTOM_DSDT_FILE) ;
+
+endif
+
+obj-$(CONFIG_ACPI)		+= tables.o
+
+#
+# ACPI Core Subsystem (Interpreter)
+#
+obj-$(CONFIG_ACPI)		+= acpi.o \
+					acpica/
+
+# All the builtin files are in the "acpi." module_param namespace.
+acpi-y				+= osi.o osl.o utils.o reboot.o
+acpi-y				+= nvs.o
+
+# Power management related files
+acpi-y				+= wakeup.o
+acpi-$(CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT) += sleep.o
+acpi-y				+= device_sysfs.o device_pm.o
+acpi-$(CONFIG_ACPI_SLEEP)	+= proc.o
+
+
+#
+# ACPI Bus and Device Drivers
+#
+acpi-y				+= bus.o glue.o
+acpi-y				+= scan.o mipi-disco-img.o
+acpi-y				+= resource.o
+acpi-y				+= acpi_processor.o
+acpi-y				+= processor_core.o
+acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o
+acpi-$(CONFIG_ACPI_EC)		+= ec.o
+acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
+acpi-$(CONFIG_PCI)		+= pci_root.o pci_link.o pci_irq.o
+obj-$(CONFIG_ACPI_MCFG)		+= pci_mcfg.o
+acpi-y				+= acpi_apd.o
+acpi-y				+= acpi_platform.o
+acpi-y				+= acpi_pnp.o
+acpi-y				+= power.o
+acpi-y				+= event.o
+acpi-y				+= evged.o
+acpi-y				+= sysfs.o
+acpi-y				+= property.o
+acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
+acpi-y				+= acpi_lpat.o
+acpi-$(CONFIG_ACPI_FPDT)	+= acpi_fpdt.o
+acpi-$(CONFIG_ACPI_LPIT)	+= acpi_lpit.o
+acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
+acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
+acpi-$(CONFIG_ACPI_PRMT)	+= prmt.o
+acpi-$(CONFIG_ACPI_PCC)		+= acpi_pcc.o
+acpi-$(CONFIG_ACPI_FFH)		+= acpi_ffh.o
+acpi-$(CONFIG_ACPI_MRRM)	+= acpi_mrrm.o
+
+# Address translation
+acpi-$(CONFIG_ACPI_ADXL)	+= acpi_adxl.o
+
+# These are (potentially) separate modules
+
+# IPMI may be used by other drivers, so it has to initialise before them
+obj-$(CONFIG_ACPI_IPMI)		+= acpi_ipmi.o
+
+obj-$(CONFIG_ACPI_AC) 		+= ac.o
+obj-$(CONFIG_ACPI_BUTTON)	+= button.o
+obj-$(CONFIG_ACPI_TINY_POWER_BUTTON)	+= tiny-power-button.o
+obj-$(CONFIG_ACPI_FAN)		+= fan.o
+fan-objs			:= fan_core.o
+fan-objs			+= fan_attr.o
+fan-$(CONFIG_HWMON)		+= fan_hwmon.o
+
+obj-$(CONFIG_ACPI_VIDEO)	+= video.o
+obj-$(CONFIG_ACPI_TAD)		+= acpi_tad.o
+obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
+obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
+obj-$(CONFIG_ACPI)		+= container.o
+obj-$(CONFIG_ACPI_THERMAL_LIB)	+= thermal_lib.o
+obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
+obj-$(CONFIG_ACPI_PLATFORM_PROFILE) 	+= platform_profile.o
+obj-$(CONFIG_ACPI_NFIT)		+= nfit/
+obj-$(CONFIG_ACPI_NHLT)		+= nhlt.o
+obj-$(CONFIG_ACPI_NUMA)		+= numa/
+obj-$(CONFIG_ACPI)		+= acpi_memhotplug.o
+obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
+obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
+obj-$(CONFIG_ACPI_SBS)		+= sbshc.o
+obj-$(CONFIG_ACPI_SBS)		+= sbs.o
+obj-$(CONFIG_ACPI_HED)		+= hed.o
+obj-$(CONFIG_ACPI_EC_DEBUGFS)	+= ec_sys.o
+obj-$(CONFIG_ACPI_BGRT)		+= bgrt.o
+obj-$(CONFIG_ACPI_CPPC_LIB)	+= cppc_acpi.o
+obj-$(CONFIG_ACPI_SPCR_TABLE)	+= spcr.o
+obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
+obj-$(CONFIG_ACPI_PPTT) 	+= pptt.o
+obj-$(CONFIG_ACPI_PFRUT)	+= pfr_update.o pfr_telemetry.o
+
+# processor has its own "processor." module_param namespace
+processor-y			:= processor_driver.o processor_thermal.o
+processor-$(CONFIG_ACPI_PROCESSOR_IDLE) += processor_idle.o
+processor-$(CONFIG_ACPI_CPU_FREQ_PSS)	+= processor_throttling.o
+processor-$(CONFIG_CPU_FREQ)	+= processor_perflib.o
+
+obj-$(CONFIG_ACPI_PROCESSOR_AGGREGATOR) += acpi_pad.o
+
+obj-$(CONFIG_ACPI_APEI)		+= apei/
+
+obj-$(CONFIG_ACPI_EXTLOG)	+= acpi_extlog.o
+
+obj-$(CONFIG_ACPI_CONFIGFS)	+= acpi_configfs.o
+
+obj-y				+= pmic/
+
+video-objs			+= acpi_video.o video_detect.o
+obj-y				+= dptf/
+
+obj-$(CONFIG_ARM64)		+= arm64/
+
+obj-$(CONFIG_ACPI_VIOT)		+= viot.o
+
+obj-$(CONFIG_RISCV)		+= riscv/
+obj-$(CONFIG_X86)		+= x86/