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, 118 insertions, 0 deletions

diff --git a/drivers/bcma/Kconfig b/drivers/bcma/Kconfig
new file mode 100644
index 000000000..b9558ff20
--- /dev/null
+++ b/drivers/bcma/Kconfig
@@ -0,0 +1,118 @@
+# SPDX-License-Identifier: GPL-2.0
+config BCMA_POSSIBLE
+	bool
+	depends on HAS_IOMEM && HAS_DMA
+	default y
+
+menuconfig BCMA
+	tristate "Broadcom specific AMBA"
+	depends on BCMA_POSSIBLE
+	help
+	  Bus driver for Broadcom specific Advanced Microcontroller Bus
+	  Architecture.
+
+if BCMA
+
+# Support for Block-I/O. SELECT this from the driver that needs it.
+config BCMA_BLOCKIO
+	bool
+
+config BCMA_HOST_PCI_POSSIBLE
+	bool
+	depends on PCI = y
+	default y
+
+config BCMA_HOST_PCI
+	bool "Support for BCMA on PCI-host bus"
+	depends on BCMA_HOST_PCI_POSSIBLE
+	select BCMA_DRIVER_PCI
+	default y
+
+config BCMA_HOST_SOC
+	bool "Support for BCMA in a SoC"
+	depends on HAS_IOMEM
+	help
+	  Host interface for a Broadcom AIX bus directly mapped into
+	  the memory. This only works with the Broadcom SoCs from the
+	  BCM47XX line.
+
+	  If unsure, say N
+
+config BCMA_DRIVER_PCI
+	bool "BCMA Broadcom PCI core driver"
+	depends on PCI
+	default y
+	help
+	  BCMA bus may have many versions of PCIe core. This driver
+	  supports:
+	  1) PCIe core working in clientmode
+	  2) PCIe Gen 2 clientmode core
+
+	  In general PCIe (Gen 2) clientmode core is required on PCIe
+	  hosted buses. It's responsible for initialization and basic
+	  hardware management.
+	  This driver is also prerequisite for a hostmode PCIe core
+	  support.
+
+config BCMA_DRIVER_PCI_HOSTMODE
+	bool "Driver for PCI core working in hostmode"
+	depends on MIPS && BCMA_DRIVER_PCI && PCI_DRIVERS_LEGACY && BCMA = y
+	help
+	  PCI core hostmode operation (external PCI bus).
+
+config BCMA_DRIVER_MIPS
+	bool "BCMA Broadcom MIPS core driver"
+	depends on MIPS || COMPILE_TEST
+	help
+	  Driver for the Broadcom MIPS core attached to Broadcom specific
+	  Advanced Microcontroller Bus.
+
+	  If unsure, say N
+
+config BCMA_PFLASH
+	bool
+	depends on BCMA_DRIVER_MIPS
+	default y
+
+config BCMA_SFLASH
+	bool "ChipCommon-attached serial flash support"
+	depends on BCMA_HOST_SOC
+	default y
+	help
+	  Some cheap devices have serial flash connected to the ChipCommon
+	  instead of independent SPI controller. It requires using a separated
+	  driver that implements ChipCommon specific interface communication.
+
+	  Enabling this symbol will let bcma recognize serial flash and register
+	  it as platform device.
+
+config BCMA_NFLASH
+	bool
+	depends on BCMA_DRIVER_MIPS
+	default y
+
+config BCMA_DRIVER_GMAC_CMN
+	bool "BCMA Broadcom GBIT MAC COMMON core driver"
+	help
+	  Driver for the Broadcom GBIT MAC COMMON core attached to Broadcom
+	  specific Advanced Microcontroller Bus.
+
+	  If unsure, say N
+
+config BCMA_DRIVER_GPIO
+	bool "BCMA GPIO driver"
+	depends on GPIOLIB
+	select GPIOLIB_IRQCHIP if BCMA_HOST_SOC
+	help
+	  Driver to provide access to the GPIO pins of the bcma bus.
+
+	  If unsure, say N
+
+config BCMA_DEBUG
+	bool "BCMA debugging"
+	help
+	  This turns on additional debugging messages.
+
+	  If unsure, say N
+
+endif # BCMA