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, 198 insertions, 0 deletions

diff --git a/drivers/bluetooth/btrtl.h b/drivers/bluetooth/btrtl.h
new file mode 100644
index 000000000..a2d9d34f9
--- /dev/null
+++ b/drivers/bluetooth/btrtl.h
@@ -0,0 +1,198 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  Bluetooth support for Realtek devices
+ *
+ *  Copyright (C) 2015 Endless Mobile, Inc.
+ */
+
+#define RTL_FRAG_LEN 252
+
+#define rtl_dev_err(dev, fmt, ...) bt_dev_err(dev, "RTL: " fmt, ##__VA_ARGS__)
+#define rtl_dev_warn(dev, fmt, ...) bt_dev_warn(dev, "RTL: " fmt, ##__VA_ARGS__)
+#define rtl_dev_info(dev, fmt, ...) bt_dev_info(dev, "RTL: " fmt, ##__VA_ARGS__)
+#define rtl_dev_dbg(dev, fmt, ...) bt_dev_dbg(dev, "RTL: " fmt, ##__VA_ARGS__)
+
+struct btrtl_device_info;
+
+struct rtl_chip_type_evt {
+	__u8 status;
+	__u8 type;
+} __packed;
+
+struct rtl_download_cmd {
+	__u8 index;
+	__u8 data[RTL_FRAG_LEN];
+} __packed;
+
+struct rtl_download_response {
+	__u8 status;
+	__u8 index;
+} __packed;
+
+struct rtl_rom_version_evt {
+	__u8 status;
+	__u8 version;
+} __packed;
+
+struct rtl_epatch_header {
+	__u8 signature[8];
+	__le32 fw_version;
+	__le16 num_patches;
+} __packed;
+
+struct rtl_vendor_config_entry {
+	__le16 offset;
+	__u8 len;
+	__u8 data[];
+} __packed;
+
+struct rtl_vendor_config {
+	__le32 signature;
+	__le16 total_len;
+	__u8 entry[];
+} __packed;
+
+struct rtl_epatch_header_v2 {
+	__u8   signature[8];
+	__u8   fw_version[8];
+	__le32 num_sections;
+} __packed;
+
+struct rtl_section {
+	__le32 opcode;
+	__le32 len;
+	u8     data[];
+} __packed;
+
+struct rtl_section_hdr {
+	__le16 num;
+	__le16 reserved;
+} __packed;
+
+struct rtl_common_subsec {
+	__u8   eco;
+	__u8   prio;
+	__u8   cb[2];
+	__le32 len;
+	__u8   data[];
+};
+
+struct rtl_sec_hdr {
+	__u8   eco;
+	__u8   prio;
+	__u8   key_id;
+	__u8   reserved;
+	__le32 len;
+	__u8   data[];
+} __packed;
+
+struct rtl_subsection {
+	struct list_head list;
+	u32 opcode;
+	u32 len;
+	u8 prio;
+	u8 *data;
+};
+
+struct rtl_iovec {
+	u8  *data;
+	u32 len;
+};
+
+struct rtl_vendor_cmd {
+	__u8 param[5];
+} __packed;
+
+enum {
+	REALTEK_ALT6_CONTINUOUS_TX_CHIP,
+
+	__REALTEK_NUM_FLAGS,
+};
+
+struct rtl_dump_info {
+	const char *driver_name;
+	char *controller;
+	u32  fw_version;
+};
+
+struct btrealtek_data {
+	DECLARE_BITMAP(flags, __REALTEK_NUM_FLAGS);
+
+	struct rtl_dump_info rtl_dump;
+};
+
+#define btrealtek_set_flag(hdev, nr)					\
+	do {								\
+		struct btrealtek_data *realtek = hci_get_priv((hdev));	\
+		set_bit((nr), realtek->flags);				\
+	} while (0)
+
+#define btrealtek_get_flag(hdev)					\
+	(((struct btrealtek_data *)hci_get_priv(hdev))->flags)
+
+#define btrealtek_test_flag(hdev, nr)	test_bit((nr), btrealtek_get_flag(hdev))
+
+#if IS_ENABLED(CONFIG_BT_RTL)
+
+struct btrtl_device_info *btrtl_initialize(struct hci_dev *hdev,
+					   const char *postfix);
+void btrtl_free(struct btrtl_device_info *btrtl_dev);
+int btrtl_download_firmware(struct hci_dev *hdev,
+			    struct btrtl_device_info *btrtl_dev);
+void btrtl_set_quirks(struct hci_dev *hdev,
+		      struct btrtl_device_info *btrtl_dev);
+int btrtl_setup_realtek(struct hci_dev *hdev);
+int btrtl_shutdown_realtek(struct hci_dev *hdev);
+int btrtl_get_uart_settings(struct hci_dev *hdev,
+			    struct btrtl_device_info *btrtl_dev,
+			    unsigned int *controller_baudrate,
+			    u32 *device_baudrate, bool *flow_control);
+void btrtl_set_driver_name(struct hci_dev *hdev, const char *driver_name);
+
+#else
+
+static inline struct btrtl_device_info *btrtl_initialize(struct hci_dev *hdev,
+							 const char *postfix)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void btrtl_free(struct btrtl_device_info *btrtl_dev)
+{
+}
+
+static inline int btrtl_download_firmware(struct hci_dev *hdev,
+					  struct btrtl_device_info *btrtl_dev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void btrtl_set_quirks(struct hci_dev *hdev,
+				    struct btrtl_device_info *btrtl_dev)
+{
+}
+
+static inline int btrtl_setup_realtek(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btrtl_shutdown_realtek(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btrtl_get_uart_settings(struct hci_dev *hdev,
+					  struct btrtl_device_info *btrtl_dev,
+					  unsigned int *controller_baudrate,
+					  u32 *device_baudrate,
+					  bool *flow_control)
+{
+	return -ENOENT;
+}
+
+static inline void btrtl_set_driver_name(struct hci_dev *hdev, const char *driver_name)
+{
+}
+
+#endif