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, 41 insertions, 0 deletions

diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
new file mode 100644
index 000000000..be46f1e1d
--- /dev/null
+++ b/drivers/firmware/Makefile
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel.
+#
+obj-$(CONFIG_ARM_SCPI_PROTOCOL)	+= arm_scpi.o
+obj-$(CONFIG_ARM_SDE_INTERFACE)	+= arm_sdei.o
+obj-$(CONFIG_ARM_SDEI_NMI)	+= arm_sdei_nmi.o
+obj-$(CONFIG_DMI)		+= dmi_scan.o
+obj-$(CONFIG_DMI_SYSFS)		+= dmi-sysfs.o
+obj-$(CONFIG_EDD)		+= edd.o
+obj-$(CONFIG_DMIID)		+= dmi-id.o
+obj-$(CONFIG_INTEL_STRATIX10_SERVICE) += stratix10-svc.o
+obj-$(CONFIG_INTEL_STRATIX10_RSU)     += stratix10-rsu.o
+obj-$(CONFIG_ISCSI_IBFT_FIND)	+= iscsi_ibft_find.o
+obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o
+obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
+obj-$(CONFIG_MTK_ADSP_IPC)	+= mtk-adsp-ipc.o
+obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
+obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
+obj-$(CONFIG_SYSFB)		+= sysfb.o
+obj-$(CONFIG_SYSFB_SIMPLEFB)	+= sysfb_simplefb.o
+obj-$(CONFIG_TH1520_AON_PROTOCOL) += thead,th1520-aon.o
+obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
+obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
+obj-$(CONFIG_TURRIS_MOX_RWTM)	+= turris-mox-rwtm.o
+
+obj-y				+= arm_ffa/
+obj-y				+= arm_scmi/
+obj-y				+= broadcom/
+obj-y				+= cirrus/
+obj-y				+= meson/
+obj-y				+= microchip/
+obj-$(CONFIG_GOOGLE_FIRMWARE)	+= google/
+obj-y				+= efi/
+obj-y				+= imx/
+obj-y				+= psci/
+obj-y				+= qcom/
+obj-y				+= samsung/
+obj-y				+= smccc/
+obj-y				+= tegra/
+obj-y				+= xilinx/