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, 18 insertions, 0 deletions

diff --git a/drivers/bcma/Makefile b/drivers/bcma/Makefile
new file mode 100644
index 000000000..f8c37de35
--- /dev/null
+++ b/drivers/bcma/Makefile
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+bcma-y					+= main.o scan.o core.o sprom.o
+bcma-y					+= driver_chipcommon.o driver_chipcommon_pmu.o
+bcma-y					+= driver_chipcommon_b.o
+bcma-$(CONFIG_BCMA_PFLASH)		+= driver_chipcommon_pflash.o
+bcma-$(CONFIG_BCMA_SFLASH)		+= driver_chipcommon_sflash.o
+bcma-$(CONFIG_BCMA_NFLASH)		+= driver_chipcommon_nflash.o
+bcma-$(CONFIG_BCMA_DRIVER_PCI)		+= driver_pci.o
+bcma-$(CONFIG_BCMA_DRIVER_PCI)		+= driver_pcie2.o
+bcma-$(CONFIG_BCMA_DRIVER_PCI_HOSTMODE)	+= driver_pci_host.o
+bcma-$(CONFIG_BCMA_DRIVER_MIPS)		+= driver_mips.o
+bcma-$(CONFIG_BCMA_DRIVER_GMAC_CMN)	+= driver_gmac_cmn.o
+bcma-$(CONFIG_BCMA_DRIVER_GPIO)		+= driver_gpio.o
+bcma-$(CONFIG_BCMA_HOST_PCI)		+= host_pci.o
+bcma-$(CONFIG_BCMA_HOST_SOC)		+= host_soc.o
+obj-$(CONFIG_BCMA)			+= bcma.o
+
+ccflags-$(CONFIG_BCMA_DEBUG)		:= -DDEBUG