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, 236 insertions, 0 deletions

diff --git a/drivers/firewire/packet-header-definitions.h b/drivers/firewire/packet-header-definitions.h
new file mode 100644
index 000000000..87a5a3184
--- /dev/null
+++ b/drivers/firewire/packet-header-definitions.h
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// packet-header-definitions.h - The definitions of header fields for IEEE 1394 packet.
+//
+// Copyright (c) 2024 Takashi Sakamoto
+
+#ifndef _FIREWIRE_PACKET_HEADER_DEFINITIONS_H
+#define _FIREWIRE_PACKET_HEADER_DEFINITIONS_H
+
+#include <linux/types.h>
+
+#define ASYNC_HEADER_QUADLET_COUNT		4
+
+#define ASYNC_HEADER_Q0_DESTINATION_SHIFT	16
+#define ASYNC_HEADER_Q0_DESTINATION_MASK	0xffff0000
+#define ASYNC_HEADER_Q0_TLABEL_SHIFT		10
+#define ASYNC_HEADER_Q0_TLABEL_MASK		0x0000fc00
+#define ASYNC_HEADER_Q0_RETRY_SHIFT		8
+#define ASYNC_HEADER_Q0_RETRY_MASK		0x00000300
+#define ASYNC_HEADER_Q0_TCODE_SHIFT		4
+#define ASYNC_HEADER_Q0_TCODE_MASK		0x000000f0
+#define ASYNC_HEADER_Q0_PRIORITY_SHIFT		0
+#define ASYNC_HEADER_Q0_PRIORITY_MASK		0x0000000f
+#define ASYNC_HEADER_Q1_SOURCE_SHIFT		16
+#define ASYNC_HEADER_Q1_SOURCE_MASK		0xffff0000
+#define ASYNC_HEADER_Q1_RCODE_SHIFT		12
+#define ASYNC_HEADER_Q1_RCODE_MASK		0x0000f000
+#define ASYNC_HEADER_Q1_RCODE_SHIFT		12
+#define ASYNC_HEADER_Q1_RCODE_MASK		0x0000f000
+#define ASYNC_HEADER_Q1_OFFSET_HIGH_SHIFT	0
+#define ASYNC_HEADER_Q1_OFFSET_HIGH_MASK	0x0000ffff
+#define ASYNC_HEADER_Q3_DATA_LENGTH_SHIFT	16
+#define ASYNC_HEADER_Q3_DATA_LENGTH_MASK	0xffff0000
+#define ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT	0
+#define ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK	0x0000ffff
+
+static inline unsigned int async_header_get_destination(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[0] & ASYNC_HEADER_Q0_DESTINATION_MASK) >> ASYNC_HEADER_Q0_DESTINATION_SHIFT;
+}
+
+static inline unsigned int async_header_get_tlabel(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[0] & ASYNC_HEADER_Q0_TLABEL_MASK) >> ASYNC_HEADER_Q0_TLABEL_SHIFT;
+}
+
+static inline unsigned int async_header_get_retry(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[0] & ASYNC_HEADER_Q0_RETRY_MASK) >> ASYNC_HEADER_Q0_RETRY_SHIFT;
+}
+
+static inline unsigned int async_header_get_tcode(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[0] & ASYNC_HEADER_Q0_TCODE_MASK) >> ASYNC_HEADER_Q0_TCODE_SHIFT;
+}
+
+static inline unsigned int async_header_get_priority(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[0] & ASYNC_HEADER_Q0_PRIORITY_MASK) >> ASYNC_HEADER_Q0_PRIORITY_SHIFT;
+}
+
+static inline unsigned int async_header_get_source(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[1] & ASYNC_HEADER_Q1_SOURCE_MASK) >> ASYNC_HEADER_Q1_SOURCE_SHIFT;
+}
+
+static inline unsigned int async_header_get_rcode(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[1] & ASYNC_HEADER_Q1_RCODE_MASK) >> ASYNC_HEADER_Q1_RCODE_SHIFT;
+}
+
+static inline u64 async_header_get_offset(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	u32 hi = (header[1] & ASYNC_HEADER_Q1_OFFSET_HIGH_MASK) >> ASYNC_HEADER_Q1_OFFSET_HIGH_SHIFT;
+	return (((u64)hi) << 32) | ((u64)header[2]);
+}
+
+static inline u32 async_header_get_quadlet_data(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return header[3];
+}
+
+static inline unsigned int async_header_get_data_length(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[3] & ASYNC_HEADER_Q3_DATA_LENGTH_MASK) >> ASYNC_HEADER_Q3_DATA_LENGTH_SHIFT;
+}
+
+static inline unsigned int async_header_get_extended_tcode(const u32 header[ASYNC_HEADER_QUADLET_COUNT])
+{
+	return (header[3] & ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK) >> ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT;
+}
+
+static inline void async_header_set_destination(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+						unsigned int destination)
+{
+	header[0] &= ~ASYNC_HEADER_Q0_DESTINATION_MASK;
+	header[0] |= (((u32)destination) << ASYNC_HEADER_Q0_DESTINATION_SHIFT) & ASYNC_HEADER_Q0_DESTINATION_MASK;
+}
+
+static inline void async_header_set_tlabel(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+					   unsigned int tlabel)
+{
+	header[0] &= ~ASYNC_HEADER_Q0_TLABEL_MASK;
+	header[0] |= (((u32)tlabel) << ASYNC_HEADER_Q0_TLABEL_SHIFT) & ASYNC_HEADER_Q0_TLABEL_MASK;
+}
+
+static inline void async_header_set_retry(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+					  unsigned int retry)
+{
+	header[0] &= ~ASYNC_HEADER_Q0_RETRY_MASK;
+	header[0] |= (((u32)retry) << ASYNC_HEADER_Q0_RETRY_SHIFT) & ASYNC_HEADER_Q0_RETRY_MASK;
+}
+
+static inline void async_header_set_tcode(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+					  unsigned int tcode)
+{
+	header[0] &= ~ASYNC_HEADER_Q0_TCODE_MASK;
+	header[0] |= (((u32)tcode) << ASYNC_HEADER_Q0_TCODE_SHIFT) & ASYNC_HEADER_Q0_TCODE_MASK;
+}
+
+static inline void async_header_set_priority(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+					     unsigned int priority)
+{
+	header[0] &= ~ASYNC_HEADER_Q0_PRIORITY_MASK;
+	header[0] |= (((u32)priority) << ASYNC_HEADER_Q0_PRIORITY_SHIFT) & ASYNC_HEADER_Q0_PRIORITY_MASK;
+}
+
+
+static inline void async_header_set_source(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+					   unsigned int source)
+{
+	header[1] &= ~ASYNC_HEADER_Q1_SOURCE_MASK;
+	header[1] |= (((u32)source) << ASYNC_HEADER_Q1_SOURCE_SHIFT) & ASYNC_HEADER_Q1_SOURCE_MASK;
+}
+
+static inline void async_header_set_rcode(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+					  unsigned int rcode)
+{
+	header[1] &= ~ASYNC_HEADER_Q1_RCODE_MASK;
+	header[1] |= (((u32)rcode) << ASYNC_HEADER_Q1_RCODE_SHIFT) & ASYNC_HEADER_Q1_RCODE_MASK;
+}
+
+static inline void async_header_set_offset(u32 header[ASYNC_HEADER_QUADLET_COUNT], u64 offset)
+{
+	u32 hi = (u32)(offset >> 32);
+	header[1] &= ~ASYNC_HEADER_Q1_OFFSET_HIGH_MASK;
+	header[1] |= (hi << ASYNC_HEADER_Q1_OFFSET_HIGH_SHIFT) & ASYNC_HEADER_Q1_OFFSET_HIGH_MASK;
+	header[2] = (u32)(offset & 0x00000000ffffffff);
+}
+
+static inline void async_header_set_quadlet_data(u32 header[ASYNC_HEADER_QUADLET_COUNT], u32 quadlet_data)
+{
+	header[3] = quadlet_data;
+}
+
+static inline void async_header_set_data_length(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+						unsigned int data_length)
+{
+	header[3] &= ~ASYNC_HEADER_Q3_DATA_LENGTH_MASK;
+	header[3] |= (((u32)data_length) << ASYNC_HEADER_Q3_DATA_LENGTH_SHIFT) & ASYNC_HEADER_Q3_DATA_LENGTH_MASK;
+}
+
+static inline void async_header_set_extended_tcode(u32 header[ASYNC_HEADER_QUADLET_COUNT],
+						   unsigned int extended_tcode)
+{
+	header[3] &= ~ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK;
+	header[3] |= (((u32)extended_tcode) << ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT) & ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK;
+}
+
+#define ISOC_HEADER_DATA_LENGTH_SHIFT		16
+#define ISOC_HEADER_DATA_LENGTH_MASK		0xffff0000
+#define ISOC_HEADER_TAG_SHIFT			14
+#define ISOC_HEADER_TAG_MASK			0x0000c000
+#define ISOC_HEADER_CHANNEL_SHIFT		8
+#define ISOC_HEADER_CHANNEL_MASK		0x00003f00
+#define ISOC_HEADER_TCODE_SHIFT			4
+#define ISOC_HEADER_TCODE_MASK			0x000000f0
+#define ISOC_HEADER_SY_SHIFT			0
+#define ISOC_HEADER_SY_MASK			0x0000000f
+
+static inline unsigned int isoc_header_get_data_length(u32 header)
+{
+	return (header & ISOC_HEADER_DATA_LENGTH_MASK) >> ISOC_HEADER_DATA_LENGTH_SHIFT;
+}
+
+static inline unsigned int isoc_header_get_tag(u32 header)
+{
+	return (header & ISOC_HEADER_TAG_MASK) >> ISOC_HEADER_TAG_SHIFT;
+}
+
+static inline unsigned int isoc_header_get_channel(u32 header)
+{
+	return (header & ISOC_HEADER_CHANNEL_MASK) >> ISOC_HEADER_CHANNEL_SHIFT;
+}
+
+static inline unsigned int isoc_header_get_tcode(u32 header)
+{
+	return (header & ISOC_HEADER_TCODE_MASK) >> ISOC_HEADER_TCODE_SHIFT;
+}
+
+static inline unsigned int isoc_header_get_sy(u32 header)
+{
+	return (header & ISOC_HEADER_SY_MASK) >> ISOC_HEADER_SY_SHIFT;
+}
+
+static inline void isoc_header_set_data_length(u32 *header, unsigned int data_length)
+{
+	*header &= ~ISOC_HEADER_DATA_LENGTH_MASK;
+	*header |= (((u32)data_length) << ISOC_HEADER_DATA_LENGTH_SHIFT) & ISOC_HEADER_DATA_LENGTH_MASK;
+}
+
+static inline void isoc_header_set_tag(u32 *header, unsigned int tag)
+{
+	*header &= ~ISOC_HEADER_TAG_MASK;
+	*header |= (((u32)tag) << ISOC_HEADER_TAG_SHIFT) & ISOC_HEADER_TAG_MASK;
+}
+
+static inline void isoc_header_set_channel(u32 *header, unsigned int channel)
+{
+	*header &= ~ISOC_HEADER_CHANNEL_MASK;
+	*header |= (((u32)channel) << ISOC_HEADER_CHANNEL_SHIFT) & ISOC_HEADER_CHANNEL_MASK;
+}
+
+static inline void isoc_header_set_tcode(u32 *header, unsigned int tcode)
+{
+	*header &= ~ISOC_HEADER_TCODE_MASK;
+	*header |= (((u32)tcode) << ISOC_HEADER_TCODE_SHIFT) & ISOC_HEADER_TCODE_MASK;
+}
+
+static inline void isoc_header_set_sy(u32 *header, unsigned int sy)
+{
+	*header &= ~ISOC_HEADER_SY_MASK;
+	*header |= (((u32)sy) << ISOC_HEADER_SY_SHIFT) & ISOC_HEADER_SY_MASK;
+}
+
+#endif // _FIREWIRE_PACKET_HEADER_DEFINITIONS_H