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, 117 insertions, 0 deletions

diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h
new file mode 100644
index 000000000..b4cb24231
--- /dev/null
+++ b/drivers/bluetooth/btbcm.h
@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ *  Bluetooth support for Broadcom devices
+ *
+ *  Copyright (C) 2015  Intel Corporation
+ */
+
+#define BCM_UART_CLOCK_48MHZ	0x01
+#define BCM_UART_CLOCK_24MHZ	0x02
+
+struct bcm_update_uart_baud_rate {
+	__le16 zero;
+	__le32 baud_rate;
+} __packed;
+
+struct bcm_write_uart_clock_setting {
+	__u8 type;
+} __packed;
+
+struct bcm_set_sleep_mode {
+	__u8 sleep_mode;
+	__u8 idle_host;
+	__u8 idle_dev;
+	__u8 bt_wake_active;
+	__u8 host_wake_active;
+	__u8 allow_host_sleep;
+	__u8 combine_modes;
+	__u8 tristate_control;
+	__u8 usb_auto_sleep;
+	__u8 usb_resume_timeout;
+	__u8 break_to_host;
+	__u8 pulsed_host_wake;
+} __packed;
+
+struct bcm_set_pcm_int_params {
+	__u8 routing;
+	__u8 rate;
+	__u8 frame_sync;
+	__u8 sync_mode;
+	__u8 clock_mode;
+} __packed;
+
+struct bcm_set_pcm_format_params {
+	__u8 lsb_first;
+	__u8 fill_value;
+	__u8 fill_method;
+	__u8 fill_num;
+	__u8 right_justify;
+} __packed;
+
+#if IS_ENABLED(CONFIG_BT_BCM)
+
+int btbcm_check_bdaddr(struct hci_dev *hdev);
+int btbcm_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr);
+int btbcm_patchram(struct hci_dev *hdev, const struct firmware *fw);
+int btbcm_read_pcm_int_params(struct hci_dev *hdev,
+			      struct bcm_set_pcm_int_params *params);
+int btbcm_write_pcm_int_params(struct hci_dev *hdev,
+			       const struct bcm_set_pcm_int_params *params);
+
+int btbcm_setup_patchram(struct hci_dev *hdev);
+int btbcm_setup_apple(struct hci_dev *hdev);
+
+int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode);
+int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode);
+
+#else
+
+static inline int btbcm_check_bdaddr(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_read_pcm_int_params(struct hci_dev *hdev,
+			      struct bcm_set_pcm_int_params *params)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_write_pcm_int_params(struct hci_dev *hdev,
+			       const struct bcm_set_pcm_int_params *params)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_patchram(struct hci_dev *hdev, const struct firmware *fw)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_setup_patchram(struct hci_dev *hdev)
+{
+	return 0;
+}
+
+static inline int btbcm_setup_apple(struct hci_dev *hdev)
+{
+	return 0;
+}
+
+static inline int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
+{
+	return 0;
+}
+
+static inline int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
+{
+	return 0;
+}
+
+#endif