From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read 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 Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/base/regmap/regmap-i3c.c | 71 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 drivers/base/regmap/regmap-i3c.c (limited to 'drivers/base/regmap/regmap-i3c.c') diff --git a/drivers/base/regmap/regmap-i3c.c b/drivers/base/regmap/regmap-i3c.c new file mode 100644 index 000000000..5af583d47 --- /dev/null +++ b/drivers/base/regmap/regmap-i3c.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Synopsys, Inc. and/or its affiliates. + +#include +#include +#include +#include +#include + +static int regmap_i3c_write(void *context, const void *data, size_t count) +{ + struct device *dev = context; + struct i3c_device *i3c = dev_to_i3cdev(dev); + struct i3c_xfer xfers[] = { + { + .rnw = false, + .len = count, + .data.out = data, + }, + }; + + return i3c_device_do_xfers(i3c, xfers, ARRAY_SIZE(xfers), I3C_SDR); +} + +static int regmap_i3c_read(void *context, + const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + struct device *dev = context; + struct i3c_device *i3c = dev_to_i3cdev(dev); + struct i3c_xfer xfers[2]; + + xfers[0].rnw = false; + xfers[0].len = reg_size; + xfers[0].data.out = reg; + + xfers[1].rnw = true; + xfers[1].len = val_size; + xfers[1].data.in = val; + + return i3c_device_do_xfers(i3c, xfers, ARRAY_SIZE(xfers), I3C_SDR); +} + +static const struct regmap_bus regmap_i3c = { + .write = regmap_i3c_write, + .read = regmap_i3c_read, +}; + +struct regmap *__regmap_init_i3c(struct i3c_device *i3c, + const struct regmap_config *config, + struct lock_class_key *lock_key, + const char *lock_name) +{ + return __regmap_init(&i3c->dev, ®map_i3c, &i3c->dev, config, + lock_key, lock_name); +} +EXPORT_SYMBOL_GPL(__regmap_init_i3c); + +struct regmap *__devm_regmap_init_i3c(struct i3c_device *i3c, + const struct regmap_config *config, + struct lock_class_key *lock_key, + const char *lock_name) +{ + return __devm_regmap_init(&i3c->dev, ®map_i3c, &i3c->dev, config, + lock_key, lock_name); +} +EXPORT_SYMBOL_GPL(__devm_regmap_init_i3c); + +MODULE_AUTHOR("Vitor Soares "); +MODULE_DESCRIPTION("regmap I3C Module"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1