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, 39 insertions, 0 deletions

diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
new file mode 100644
index 000000000..eb8a022da
--- /dev/null
+++ b/drivers/perf/Makefile
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_ARM_CCI_PMU) += arm-cci.o
+obj-$(CONFIG_ARM_CCN) += arm-ccn.o
+obj-$(CONFIG_ARM_CMN) += arm-cmn.o
+obj-$(CONFIG_ARM_DSU_PMU) += arm_dsu_pmu.o
+obj-$(CONFIG_ARM_NI) += arm-ni.o
+obj-$(CONFIG_ARM_PMU) += arm_pmu.o arm_pmu_platform.o
+obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o
+obj-$(CONFIG_ARM_PMUV3) += arm_pmuv3.o
+obj-$(CONFIG_ARM_V6_PMU) += arm_v6_pmu.o
+obj-$(CONFIG_ARM_V7_PMU) += arm_v7_pmu.o
+obj-$(CONFIG_ARM_XSCALE_PMU) += arm_xscale_pmu.o
+obj-$(CONFIG_ARM_SMMU_V3_PMU) += arm_smmuv3_pmu.o
+obj-$(CONFIG_FSL_IMX8_DDR_PMU) += fsl_imx8_ddr_perf.o
+obj-$(CONFIG_FSL_IMX9_DDR_PMU) += fsl_imx9_ddr_perf.o
+obj-$(CONFIG_FUJITSU_UNCORE_PMU) += fujitsu_uncore_pmu.o
+obj-$(CONFIG_HISI_PMU) += hisilicon/
+obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
+obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
+obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
+obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
+obj-$(CONFIG_RISCV_PMU_SBI) += riscv_pmu_sbi.o
+obj-$(CONFIG_STARFIVE_STARLINK_PMU) += starfive_starlink_pmu.o
+obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
+obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
+obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
+obj-$(CONFIG_ARM64_BRBE) += arm_brbe.o
+obj-$(CONFIG_ARM_DMC620_PMU) += arm_dmc620_pmu.o
+obj-$(CONFIG_MARVELL_CN10K_TAD_PMU) += marvell_cn10k_tad_pmu.o
+obj-$(CONFIG_MARVELL_CN10K_DDR_PMU) += marvell_cn10k_ddr_pmu.o
+obj-$(CONFIG_MARVELL_PEM_PMU) += marvell_pem_pmu.o
+obj-$(CONFIG_APPLE_M1_CPU_PMU) += apple_m1_cpu_pmu.o
+obj-$(CONFIG_ALIBABA_UNCORE_DRW_PMU) += alibaba_uncore_drw_pmu.o
+obj-$(CONFIG_DWC_PCIE_PMU) += dwc_pcie_pmu.o
+obj-$(CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU) += arm_cspmu/
+obj-$(CONFIG_MESON_DDR_PMU) += amlogic/
+obj-$(CONFIG_CXL_PMU) += cxl_pmu.o
+obj-$(CONFIG_NVIDIA_TEGRA410_CMEM_LATENCY_PMU) += nvidia_t410_cmem_latency_pmu.o
+obj-$(CONFIG_NVIDIA_TEGRA410_C2C_PMU) += nvidia_t410_c2c_pmu.o