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, 32 insertions, 0 deletions

diff --git a/drivers/mtd/hyperbus/Kconfig b/drivers/mtd/hyperbus/Kconfig
new file mode 100644
index 000000000..30ffc4c16
--- /dev/null
+++ b/drivers/mtd/hyperbus/Kconfig
@@ -0,0 +1,32 @@
+menuconfig MTD_HYPERBUS
+	tristate "HyperBus support"
+	depends on HAS_IOMEM
+	select MTD_CFI
+	select MTD_MAP_BANK_WIDTH_2
+	select MTD_CFI_AMDSTD
+	select MTD_COMPLEX_MAPPINGS
+	help
+	  This is the framework for the HyperBus which can be used by
+	  the HyperBus Controller driver to communicate with
+	  HyperFlash. See Cypress HyperBus specification for more
+	  details
+
+if MTD_HYPERBUS
+
+config HBMC_AM654
+	tristate "HyperBus controller driver for AM65x SoC"
+	depends on ARCH_K3 || COMPILE_TEST
+	select MULTIPLEXER
+	imply MUX_MMIO
+	help
+	 This is the driver for HyperBus controller on TI's AM65x and
+	 other SoCs
+
+config RPCIF_HYPERBUS
+	tristate "Renesas RPC-IF HyperBus driver"
+	depends on RENESAS_RPCIF
+	depends on MTD_CFI_BE_BYTE_SWAP
+	help
+	  This option includes Renesas RPC-IF HyperBus support.
+
+endif # MTD_HYPERBUS