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, 129 insertions, 0 deletions

diff --git a/drivers/hid/hid-haptic.h b/drivers/hid/hid-haptic.h
new file mode 100644
index 000000000..6332991a7
--- /dev/null
+++ b/drivers/hid/hid-haptic.h
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  HID Haptic support for Linux
+ *
+ *  Copyright (c) 2021 Angela Czubak <acz@semihalf.com>
+ */
+
+#include <linux/hid.h>
+
+#define HID_HAPTIC_ORDINAL_WAVEFORMNONE 1
+#define HID_HAPTIC_ORDINAL_WAVEFORMSTOP 2
+
+#define HID_HAPTIC_MODE_DEVICE 0
+#define HID_HAPTIC_MODE_HOST 1
+
+struct hid_haptic_effect {
+	u8 *report_buf;
+	struct input_dev *input_dev;
+	struct work_struct work;
+	struct list_head control;
+	struct mutex control_mutex;
+};
+
+struct hid_haptic_effect_node {
+	struct list_head node;
+	struct file *file;
+};
+
+struct hid_haptic_device {
+	struct input_dev *input_dev;
+	struct hid_device *hdev;
+	struct hid_report *auto_trigger_report;
+	struct mutex auto_trigger_mutex;
+	struct workqueue_struct *wq;
+	struct hid_report *manual_trigger_report;
+	struct mutex manual_trigger_mutex;
+	size_t manual_trigger_report_len;
+	int pressed_state;
+	s32 pressure_sum;
+	s32 force_logical_minimum;
+	s32 force_physical_minimum;
+	s32 force_resolution;
+	u32 mode;
+	u32 default_auto_trigger;
+	u32 vendor_page;
+	u32 vendor_id;
+	u32 max_waveform_id;
+	u32 max_duration_id;
+	u16 *hid_usage_map;
+	u32 *duration_map;
+	u16 press_ordinal;
+	u16 release_ordinal;
+	struct hid_haptic_effect *effect;
+	struct hid_haptic_effect stop_effect;
+};
+
+#if IS_ENABLED(CONFIG_HID_HAPTIC)
+void hid_haptic_feature_mapping(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_field *field, struct hid_usage
+				*usage);
+bool hid_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
+				    struct hid_input *hi, struct hid_field *field);
+int hid_haptic_input_mapping(struct hid_device *hdev,
+			     struct hid_haptic_device *haptic,
+			     struct hid_input *hi,
+			     struct hid_field *field, struct hid_usage *usage,
+			     unsigned long **bit, int *max);
+int hid_haptic_input_configured(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_input *hi);
+int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device *haptic,
+		    struct input_dev *dev);
+void hid_haptic_handle_press_release(struct hid_haptic_device *haptic);
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic);
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				  __s32 pressure);
+#else
+static inline
+void hid_haptic_feature_mapping(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_field *field, struct hid_usage
+				*usage)
+{}
+static inline
+bool hid_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
+				    struct hid_input *hi, struct hid_field *field)
+{
+	return false;
+}
+static inline
+int hid_haptic_input_mapping(struct hid_device *hdev,
+			     struct hid_haptic_device *haptic,
+			     struct hid_input *hi,
+			     struct hid_field *field, struct hid_usage *usage,
+			     unsigned long **bit, int *max)
+{
+	return 0;
+}
+static inline
+int hid_haptic_input_configured(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_input *hi)
+{
+	return 0;
+}
+static inline
+void hid_haptic_reset(struct hid_device *hdev, struct hid_haptic_device *haptic)
+{}
+static inline
+int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device *haptic,
+		    struct input_dev *dev)
+{
+	return 0;
+}
+static inline
+void hid_haptic_handle_press_release(struct hid_haptic_device *haptic) {}
+static inline
+bool hid_haptic_handle_input(struct hid_haptic_device *haptic)
+{
+	return false;
+}
+static inline
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic) {}
+static inline
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				  __s32 pressure)
+{}
+#endif