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, 23 insertions, 0 deletions

diff --git a/drivers/net/ipa/Kconfig b/drivers/net/ipa/Kconfig
new file mode 100644
index 000000000..a9aff1b79
--- /dev/null
+++ b/drivers/net/ipa/Kconfig
@@ -0,0 +1,23 @@
+config QCOM_IPA
+	tristate "Qualcomm IPA support"
+	depends on NET && QCOM_SMEM
+	depends on ARCH_QCOM || COMPILE_TEST
+	depends on INTERCONNECT
+	depends on QCOM_RPROC_COMMON || (QCOM_RPROC_COMMON=n && COMPILE_TEST)
+	depends on QCOM_AOSS_QMP || QCOM_AOSS_QMP=n
+	select QCOM_MDT_LOADER
+	select QCOM_PAS
+	select QCOM_QMI_HELPERS
+	help
+	  Choose Y or M here to include support for the Qualcomm
+	  IP Accelerator (IPA), a hardware block present in some
+	  Qualcomm SoCs.  The IPA is a programmable protocol processor
+	  that is capable of generic hardware handling of IP packets,
+	  including routing, filtering, and NAT.  Currently the IPA
+	  driver supports only basic transport of network traffic
+	  between the AP and modem.
+
+	  Note that if selected, the selection type must match that
+	  of QCOM_Q6V5_COMMON (Y or M).
+
+	  If unsure, say N.