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, 302 insertions, 0 deletions

diff --git a/drivers/firewire/phy-packet-definitions.h b/drivers/firewire/phy-packet-definitions.h
new file mode 100644
index 000000000..03c7c6067
--- /dev/null
+++ b/drivers/firewire/phy-packet-definitions.h
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// phy-packet-definitions.h - The definitions of phy packet for IEEE 1394.
+//
+// Copyright (c) 2024 Takashi Sakamoto
+
+#ifndef _FIREWIRE_PHY_PACKET_DEFINITIONS_H
+#define _FIREWIRE_PHY_PACKET_DEFINITIONS_H
+
+#define PACKET_IDENTIFIER_MASK				0xc0000000
+#define PACKET_IDENTIFIER_SHIFT				30
+
+static inline unsigned int phy_packet_get_packet_identifier(u32 quadlet)
+{
+	return (quadlet & PACKET_IDENTIFIER_MASK) >> PACKET_IDENTIFIER_SHIFT;
+}
+
+static inline void phy_packet_set_packet_identifier(u32 *quadlet, unsigned int packet_identifier)
+{
+	*quadlet &= ~PACKET_IDENTIFIER_MASK;
+	*quadlet |= (packet_identifier << PACKET_IDENTIFIER_SHIFT) & PACKET_IDENTIFIER_MASK;
+}
+
+#define PHY_PACKET_PACKET_IDENTIFIER_PHY_CONFIG		0
+
+#define PHY_CONFIG_ROOT_ID_MASK				0x3f000000
+#define PHY_CONFIG_ROOT_ID_SHIFT			24
+#define PHY_CONFIG_FORCE_ROOT_NODE_MASK			0x00800000
+#define PHY_CONFIG_FORCE_ROOT_NODE_SHIFT		23
+#define PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK		0x00400000
+#define PHY_CONFIG_GAP_COUNT_OPTIMIZATION_SHIFT		22
+#define PHY_CONFIG_GAP_COUNT_MASK			0x003f0000
+#define PHY_CONFIG_GAP_COUNT_SHIFT			16
+
+static inline unsigned int phy_packet_phy_config_get_root_id(u32 quadlet)
+{
+	return (quadlet & PHY_CONFIG_ROOT_ID_MASK) >> PHY_CONFIG_ROOT_ID_SHIFT;
+}
+
+static inline void phy_packet_phy_config_set_root_id(u32 *quadlet, unsigned int root_id)
+{
+	*quadlet &= ~PHY_CONFIG_ROOT_ID_MASK;
+	*quadlet |= (root_id << PHY_CONFIG_ROOT_ID_SHIFT) & PHY_CONFIG_ROOT_ID_MASK;
+}
+
+static inline bool phy_packet_phy_config_get_force_root_node(u32 quadlet)
+{
+	return (quadlet & PHY_CONFIG_FORCE_ROOT_NODE_MASK) >> PHY_CONFIG_FORCE_ROOT_NODE_SHIFT;
+}
+
+static inline void phy_packet_phy_config_set_force_root_node(u32 *quadlet, bool has_force_root_node)
+{
+	*quadlet &= ~PHY_CONFIG_FORCE_ROOT_NODE_MASK;
+	*quadlet |= (has_force_root_node << PHY_CONFIG_FORCE_ROOT_NODE_SHIFT) & PHY_CONFIG_FORCE_ROOT_NODE_MASK;
+}
+
+static inline bool phy_packet_phy_config_get_gap_count_optimization(u32 quadlet)
+{
+	return (quadlet & PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK) >> PHY_CONFIG_GAP_COUNT_OPTIMIZATION_SHIFT;
+}
+
+static inline void phy_packet_phy_config_set_gap_count_optimization(u32 *quadlet, bool has_gap_count_optimization)
+{
+	*quadlet &= ~PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK;
+	*quadlet |= (has_gap_count_optimization << PHY_CONFIG_GAP_COUNT_OPTIMIZATION_SHIFT) & PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK;
+}
+
+static inline unsigned int phy_packet_phy_config_get_gap_count(u32 quadlet)
+{
+	return (quadlet & PHY_CONFIG_GAP_COUNT_MASK) >> PHY_CONFIG_GAP_COUNT_SHIFT;
+}
+
+static inline void phy_packet_phy_config_set_gap_count(u32 *quadlet, unsigned int gap_count)
+{
+	*quadlet &= ~PHY_CONFIG_GAP_COUNT_MASK;
+	*quadlet |= (gap_count << PHY_CONFIG_GAP_COUNT_SHIFT) & PHY_CONFIG_GAP_COUNT_MASK;
+}
+
+#define PHY_PACKET_PACKET_IDENTIFIER_SELF_ID		2
+
+#define SELF_ID_PHY_ID_MASK				0x3f000000
+#define SELF_ID_PHY_ID_SHIFT				24
+#define SELF_ID_EXTENDED_MASK				0x00800000
+#define SELF_ID_EXTENDED_SHIFT				23
+#define SELF_ID_MORE_PACKETS_MASK			0x00000001
+#define SELF_ID_MORE_PACKETS_SHIFT			0
+
+#define SELF_ID_ZERO_LINK_ACTIVE_MASK			0x00400000
+#define SELF_ID_ZERO_LINK_ACTIVE_SHIFT			22
+#define SELF_ID_ZERO_GAP_COUNT_MASK			0x003f0000
+#define SELF_ID_ZERO_GAP_COUNT_SHIFT			16
+#define SELF_ID_ZERO_SCODE_MASK				0x0000c000
+#define SELF_ID_ZERO_SCODE_SHIFT			14
+#define SELF_ID_ZERO_CONTENDER_MASK			0x00000800
+#define SELF_ID_ZERO_CONTENDER_SHIFT			11
+#define SELF_ID_ZERO_POWER_CLASS_MASK			0x00000700
+#define SELF_ID_ZERO_POWER_CLASS_SHIFT			8
+#define SELF_ID_ZERO_INITIATED_RESET_MASK		0x00000002
+#define SELF_ID_ZERO_INITIATED_RESET_SHIFT		1
+
+#define SELF_ID_EXTENDED_SEQUENCE_MASK			0x00700000
+#define SELF_ID_EXTENDED_SEQUENCE_SHIFT			20
+
+#define SELF_ID_PORT_STATUS_MASK			0x3
+
+#define SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT		4
+
+static inline unsigned int phy_packet_self_id_get_phy_id(u32 quadlet)
+{
+	return (quadlet & SELF_ID_PHY_ID_MASK)  >> SELF_ID_PHY_ID_SHIFT;
+}
+
+static inline void phy_packet_self_id_set_phy_id(u32 *quadlet, unsigned int phy_id)
+{
+	*quadlet &= ~SELF_ID_PHY_ID_MASK;
+	*quadlet |= (phy_id << SELF_ID_PHY_ID_SHIFT) & SELF_ID_PHY_ID_MASK;
+}
+
+static inline bool phy_packet_self_id_get_extended(u32 quadlet)
+{
+	return (quadlet & SELF_ID_EXTENDED_MASK) >> SELF_ID_EXTENDED_SHIFT;
+}
+
+static inline void phy_packet_self_id_set_extended(u32 *quadlet, bool extended)
+{
+	*quadlet &= ~SELF_ID_EXTENDED_MASK;
+	*quadlet |= (extended << SELF_ID_EXTENDED_SHIFT) & SELF_ID_EXTENDED_MASK;
+}
+
+static inline bool phy_packet_self_id_zero_get_link_active(u32 quadlet)
+{
+	return (quadlet & SELF_ID_ZERO_LINK_ACTIVE_MASK) >> SELF_ID_ZERO_LINK_ACTIVE_SHIFT;
+}
+
+static inline void phy_packet_self_id_zero_set_link_active(u32 *quadlet, bool is_active)
+{
+	*quadlet &= ~SELF_ID_ZERO_LINK_ACTIVE_MASK;
+	*quadlet |= (is_active << SELF_ID_ZERO_LINK_ACTIVE_SHIFT) & SELF_ID_ZERO_LINK_ACTIVE_MASK;
+}
+
+static inline unsigned int phy_packet_self_id_zero_get_gap_count(u32 quadlet)
+{
+	return (quadlet & SELF_ID_ZERO_GAP_COUNT_MASK) >> SELF_ID_ZERO_GAP_COUNT_SHIFT;
+}
+
+static inline void phy_packet_self_id_zero_set_gap_count(u32 *quadlet, unsigned int gap_count)
+{
+	*quadlet &= ~SELF_ID_ZERO_GAP_COUNT_MASK;
+	*quadlet |= (gap_count << SELF_ID_ZERO_GAP_COUNT_SHIFT) & SELF_ID_ZERO_GAP_COUNT_MASK;
+}
+
+static inline unsigned int phy_packet_self_id_zero_get_scode(u32 quadlet)
+{
+	return (quadlet & SELF_ID_ZERO_SCODE_MASK) >> SELF_ID_ZERO_SCODE_SHIFT;
+}
+
+static inline void phy_packet_self_id_zero_set_scode(u32 *quadlet, unsigned int speed)
+{
+	*quadlet &= ~SELF_ID_ZERO_SCODE_MASK;
+	*quadlet |= (speed << SELF_ID_ZERO_SCODE_SHIFT) & SELF_ID_ZERO_SCODE_MASK;
+}
+
+static inline bool phy_packet_self_id_zero_get_contender(u32 quadlet)
+{
+	return (quadlet & SELF_ID_ZERO_CONTENDER_MASK) >> SELF_ID_ZERO_CONTENDER_SHIFT;
+}
+
+static inline void phy_packet_self_id_zero_set_contender(u32 *quadlet, bool is_contender)
+{
+	*quadlet &= ~SELF_ID_ZERO_CONTENDER_MASK;
+	*quadlet |= (is_contender << SELF_ID_ZERO_CONTENDER_SHIFT) & SELF_ID_ZERO_CONTENDER_MASK;
+}
+
+static inline unsigned int phy_packet_self_id_zero_get_power_class(u32 quadlet)
+{
+	return (quadlet & SELF_ID_ZERO_POWER_CLASS_MASK) >> SELF_ID_ZERO_POWER_CLASS_SHIFT;
+}
+
+static inline void phy_packet_self_id_zero_set_power_class(u32 *quadlet, unsigned int power_class)
+{
+	*quadlet &= ~SELF_ID_ZERO_POWER_CLASS_MASK;
+	*quadlet |= (power_class << SELF_ID_ZERO_POWER_CLASS_SHIFT) & SELF_ID_ZERO_POWER_CLASS_MASK;
+}
+
+static inline bool phy_packet_self_id_zero_get_initiated_reset(u32 quadlet)
+{
+	return (quadlet & SELF_ID_ZERO_INITIATED_RESET_MASK) >> SELF_ID_ZERO_INITIATED_RESET_SHIFT;
+}
+
+static inline void phy_packet_self_id_zero_set_initiated_reset(u32 *quadlet, bool is_initiated_reset)
+{
+	*quadlet &= ~SELF_ID_ZERO_INITIATED_RESET_MASK;
+	*quadlet |= (is_initiated_reset << SELF_ID_ZERO_INITIATED_RESET_SHIFT) & SELF_ID_ZERO_INITIATED_RESET_MASK;
+}
+
+static inline bool phy_packet_self_id_get_more_packets(u32 quadlet)
+{
+	return (quadlet & SELF_ID_MORE_PACKETS_MASK) >> SELF_ID_MORE_PACKETS_SHIFT;
+}
+
+static inline void phy_packet_self_id_set_more_packets(u32 *quadlet, bool is_more_packets)
+{
+	*quadlet &= ~SELF_ID_MORE_PACKETS_MASK;
+	*quadlet |= (is_more_packets << SELF_ID_MORE_PACKETS_SHIFT) & SELF_ID_MORE_PACKETS_MASK;
+}
+
+static inline unsigned int phy_packet_self_id_extended_get_sequence(u32 quadlet)
+{
+	return (quadlet & SELF_ID_EXTENDED_SEQUENCE_MASK) >> SELF_ID_EXTENDED_SEQUENCE_SHIFT;
+}
+
+static inline void phy_packet_self_id_extended_set_sequence(u32 *quadlet, unsigned int sequence)
+{
+	*quadlet &= ~SELF_ID_EXTENDED_SEQUENCE_MASK;
+	*quadlet |= (sequence << SELF_ID_EXTENDED_SHIFT) & SELF_ID_EXTENDED_SEQUENCE_MASK;
+}
+
+struct self_id_sequence_enumerator {
+	const u32 *cursor;
+	unsigned int quadlet_count;
+};
+
+static inline const u32 *self_id_sequence_enumerator_next(
+		struct self_id_sequence_enumerator *enumerator, unsigned int *quadlet_count)
+{
+	const u32 *self_id_sequence, *cursor;
+	u32 quadlet;
+	unsigned int count;
+	unsigned int sequence;
+
+	if (enumerator->cursor == NULL || enumerator->quadlet_count == 0)
+		return ERR_PTR(-ENODATA);
+	cursor = enumerator->cursor;
+	count = 1;
+
+	quadlet = *cursor;
+	sequence = 0;
+	while (phy_packet_self_id_get_more_packets(quadlet)) {
+		if (count >= enumerator->quadlet_count ||
+		    count >= SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT)
+			return ERR_PTR(-EPROTO);
+		++cursor;
+		++count;
+		quadlet = *cursor;
+
+		if (!phy_packet_self_id_get_extended(quadlet) ||
+		    sequence != phy_packet_self_id_extended_get_sequence(quadlet))
+			return ERR_PTR(-EPROTO);
+		++sequence;
+	}
+
+	*quadlet_count = count;
+	self_id_sequence = enumerator->cursor;
+
+	enumerator->cursor += count;
+	enumerator->quadlet_count -= count;
+
+	return self_id_sequence;
+}
+
+enum phy_packet_self_id_port_status {
+	PHY_PACKET_SELF_ID_PORT_STATUS_NONE = 0,
+	PHY_PACKET_SELF_ID_PORT_STATUS_NCONN = 1,
+	PHY_PACKET_SELF_ID_PORT_STATUS_PARENT = 2,
+	PHY_PACKET_SELF_ID_PORT_STATUS_CHILD = 3,
+};
+
+static inline unsigned int self_id_sequence_get_port_capacity(unsigned int quadlet_count)
+{
+	return quadlet_count * 8 - 5;
+}
+
+static inline enum phy_packet_self_id_port_status self_id_sequence_get_port_status(
+		const u32 *self_id_sequence, unsigned int quadlet_count, unsigned int port_index)
+{
+	unsigned int index, shift;
+
+	index = (port_index + 5) / 8;
+	shift = 16 - ((port_index + 5) % 8) * 2;
+
+	if (index < quadlet_count && index < SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT)
+		return (self_id_sequence[index] >> shift) & SELF_ID_PORT_STATUS_MASK;
+
+	return PHY_PACKET_SELF_ID_PORT_STATUS_NONE;
+}
+
+static inline void self_id_sequence_set_port_status(u32 *self_id_sequence, unsigned int quadlet_count,
+						    unsigned int port_index,
+						    enum phy_packet_self_id_port_status status)
+{
+	unsigned int index, shift;
+
+	index = (port_index + 5) / 8;
+	shift = 16 - ((port_index + 5) % 8) * 2;
+
+	if (index < quadlet_count) {
+		self_id_sequence[index] &= ~(SELF_ID_PORT_STATUS_MASK << shift);
+		self_id_sequence[index] |= status << shift;
+	}
+}
+
+#endif // _FIREWIRE_PHY_PACKET_DEFINITIONS_H