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, 114 insertions, 0 deletions

diff --git a/drivers/input/mouse/sentelic.h b/drivers/input/mouse/sentelic.h
new file mode 100644
index 000000000..02cac0e7a
--- /dev/null
+++ b/drivers/input/mouse/sentelic.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*-
+ * Finger Sensing Pad PS/2 mouse driver.
+ *
+ * Copyright (C) 2005-2007 Asia Vital Components Co., Ltd.
+ * Copyright (C) 2005-2012 Tai-hwa Liang, Sentelic Corporation.
+ */
+
+#ifndef	__SENTELIC_H
+#define	__SENTELIC_H
+
+/* Finger-sensing Pad information registers */
+#define	FSP_REG_DEVICE_ID	0x00
+#define	FSP_REG_VERSION		0x01
+#define	FSP_REG_REVISION	0x04
+#define	FSP_REG_TMOD_STATUS1	0x0B
+#define	FSP_BIT_NO_ROTATION	BIT(3)
+#define	FSP_REG_PAGE_CTRL	0x0F
+
+/* Finger-sensing Pad control registers */
+#define	FSP_REG_SYSCTL1		0x10
+#define	FSP_BIT_EN_REG_CLK	BIT(5)
+#define	FSP_REG_TMOD_STATUS	0x20
+#define	FSP_REG_OPC_QDOWN	0x31
+#define	FSP_BIT_EN_OPC_TAG	BIT(7)
+#define	FSP_REG_OPTZ_XLO	0x34
+#define	FSP_REG_OPTZ_XHI	0x35
+#define	FSP_REG_OPTZ_YLO	0x36
+#define	FSP_REG_OPTZ_YHI	0x37
+#define	FSP_REG_SYSCTL5		0x40
+#define	FSP_BIT_90_DEGREE	BIT(0)
+#define	FSP_BIT_EN_MSID6	BIT(1)
+#define	FSP_BIT_EN_MSID7	BIT(2)
+#define	FSP_BIT_EN_MSID8	BIT(3)
+#define	FSP_BIT_EN_AUTO_MSID8	BIT(5)
+#define	FSP_BIT_EN_PKT_G0	BIT(6)
+
+#define	FSP_REG_ONPAD_CTL	0x43
+#define	FSP_BIT_ONPAD_ENABLE	BIT(0)
+#define	FSP_BIT_ONPAD_FBBB	BIT(1)
+#define	FSP_BIT_FIX_VSCR	BIT(3)
+#define	FSP_BIT_FIX_HSCR	BIT(5)
+#define	FSP_BIT_DRAG_LOCK	BIT(6)
+
+#define	FSP_REG_SWC1		(0x90)
+#define	FSP_BIT_SWC1_EN_ABS_1F	BIT(0)
+#define	FSP_BIT_SWC1_EN_GID	BIT(1)
+#define	FSP_BIT_SWC1_EN_ABS_2F	BIT(2)
+#define	FSP_BIT_SWC1_EN_FUP_OUT	BIT(3)
+#define	FSP_BIT_SWC1_EN_ABS_CON	BIT(4)
+#define	FSP_BIT_SWC1_GST_GRP0	BIT(5)
+#define	FSP_BIT_SWC1_GST_GRP1	BIT(6)
+#define	FSP_BIT_SWC1_BX_COMPAT	BIT(7)
+
+#define	FSP_PAGE_0B		(0x0b)
+#define	FSP_PAGE_82		(0x82)
+#define	FSP_PAGE_DEFAULT	FSP_PAGE_82
+
+#define	FSP_REG_SN0		(0x40)
+#define	FSP_REG_SN1		(0x41)
+#define	FSP_REG_SN2		(0x42)
+
+/* Finger-sensing Pad packet formating related definitions */
+
+/* absolute packet type */
+#define	FSP_PKT_TYPE_NORMAL	(0x00)
+#define	FSP_PKT_TYPE_ABS	(0x01)
+#define	FSP_PKT_TYPE_NOTIFY	(0x02)
+#define	FSP_PKT_TYPE_NORMAL_OPC	(0x03)
+#define	FSP_PKT_TYPE_SHIFT	(6)
+
+/* bit definitions for the first byte of report packet */
+#define	FSP_PB0_LBTN		BIT(0)
+#define	FSP_PB0_RBTN		BIT(1)
+#define	FSP_PB0_MBTN		BIT(2)
+#define	FSP_PB0_MFMC_FGR2	FSP_PB0_MBTN
+#define	FSP_PB0_MUST_SET	BIT(3)
+#define	FSP_PB0_PHY_BTN		BIT(4)
+#define	FSP_PB0_MFMC		BIT(5)
+
+/* hardware revisions */
+#define	FSP_VER_STL3888_A4	(0xC1)
+#define	FSP_VER_STL3888_B0	(0xD0)
+#define	FSP_VER_STL3888_B1	(0xD1)
+#define	FSP_VER_STL3888_B2	(0xD2)
+#define	FSP_VER_STL3888_C0	(0xE0)
+#define	FSP_VER_STL3888_C1	(0xE1)
+#define	FSP_VER_STL3888_D0	(0xE2)
+#define	FSP_VER_STL3888_D1	(0xE3)
+#define	FSP_VER_STL3888_E0	(0xE4)
+
+#ifdef __KERNEL__
+
+struct fsp_data {
+	unsigned char	ver;		/* hardware version */
+	unsigned char	rev;		/* hardware revison */
+	unsigned int	buttons;	/* Number of buttons */
+	unsigned int	flags;
+#define	FSPDRV_FLAG_EN_OPC	(0x001)	/* enable on-pad clicking */
+
+	bool		vscroll;	/* Vertical scroll zone enabled */
+	bool		hscroll;	/* Horizontal scroll zone enabled */
+
+	unsigned char	last_reg;	/* Last register we requested read from */
+	unsigned char	last_val;
+	unsigned int	last_mt_fgr;	/* Last seen finger(multitouch) */
+};
+
+extern int fsp_detect(struct psmouse *psmouse, bool set_properties);
+extern int fsp_init(struct psmouse *psmouse);
+
+#endif	/* __KERNEL__ */
+
+#endif	/* !__SENTELIC_H */