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-mdio.c | 121 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 drivers/base/regmap/regmap-mdio.c (limited to 'drivers/base/regmap/regmap-mdio.c') diff --git a/drivers/base/regmap/regmap-mdio.c b/drivers/base/regmap/regmap-mdio.c new file mode 100644 index 000000000..9573bf3b5 --- /dev/null +++ b/drivers/base/regmap/regmap-mdio.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include + +#define REGVAL_MASK GENMASK(15, 0) +#define REGNUM_C22_MASK GENMASK(4, 0) +/* Clause-45 mask includes the device type (5 bit) and actual register number (16 bit) */ +#define REGNUM_C45_MASK GENMASK(20, 0) + +static int regmap_mdio_c22_read(void *context, unsigned int reg, unsigned int *val) +{ + struct mdio_device *mdio_dev = context; + int ret; + + if (unlikely(reg & ~REGNUM_C22_MASK)) + return -ENXIO; + + ret = mdiodev_read(mdio_dev, reg); + if (ret < 0) + return ret; + + *val = ret & REGVAL_MASK; + + return 0; +} + +static int regmap_mdio_c22_write(void *context, unsigned int reg, unsigned int val) +{ + struct mdio_device *mdio_dev = context; + + if (unlikely(reg & ~REGNUM_C22_MASK)) + return -ENXIO; + + return mdiodev_write(mdio_dev, reg, val); +} + +static const struct regmap_bus regmap_mdio_c22_bus = { + .reg_write = regmap_mdio_c22_write, + .reg_read = regmap_mdio_c22_read, +}; + +static int regmap_mdio_c45_read(void *context, unsigned int reg, unsigned int *val) +{ + struct mdio_device *mdio_dev = context; + unsigned int devad; + int ret; + + if (unlikely(reg & ~REGNUM_C45_MASK)) + return -ENXIO; + + devad = reg >> REGMAP_MDIO_C45_DEVAD_SHIFT; + reg = reg & REGMAP_MDIO_C45_REGNUM_MASK; + + ret = mdiodev_c45_read(mdio_dev, devad, reg); + if (ret < 0) + return ret; + + *val = ret & REGVAL_MASK; + + return 0; +} + +static int regmap_mdio_c45_write(void *context, unsigned int reg, unsigned int val) +{ + struct mdio_device *mdio_dev = context; + unsigned int devad; + + if (unlikely(reg & ~REGNUM_C45_MASK)) + return -ENXIO; + + devad = reg >> REGMAP_MDIO_C45_DEVAD_SHIFT; + reg = reg & REGMAP_MDIO_C45_REGNUM_MASK; + + return mdiodev_c45_write(mdio_dev, devad, reg, val); +} + +static const struct regmap_bus regmap_mdio_c45_bus = { + .reg_write = regmap_mdio_c45_write, + .reg_read = regmap_mdio_c45_read, +}; + +struct regmap *__regmap_init_mdio(struct mdio_device *mdio_dev, + const struct regmap_config *config, struct lock_class_key *lock_key, + const char *lock_name) +{ + const struct regmap_bus *bus; + + if (config->reg_bits == 5 && config->val_bits == 16) + bus = ®map_mdio_c22_bus; + else if (config->reg_bits == 21 && config->val_bits == 16) + bus = ®map_mdio_c45_bus; + else + return ERR_PTR(-EOPNOTSUPP); + + return __regmap_init(&mdio_dev->dev, bus, mdio_dev, config, lock_key, lock_name); +} +EXPORT_SYMBOL_GPL(__regmap_init_mdio); + +struct regmap *__devm_regmap_init_mdio(struct mdio_device *mdio_dev, + const struct regmap_config *config, struct lock_class_key *lock_key, + const char *lock_name) +{ + const struct regmap_bus *bus; + + if (config->reg_bits == 5 && config->val_bits == 16) + bus = ®map_mdio_c22_bus; + else if (config->reg_bits == 21 && config->val_bits == 16) + bus = ®map_mdio_c45_bus; + else + return ERR_PTR(-EOPNOTSUPP); + + return __devm_regmap_init(&mdio_dev->dev, bus, mdio_dev, config, lock_key, lock_name); +} +EXPORT_SYMBOL_GPL(__devm_regmap_init_mdio); + +MODULE_AUTHOR("Sander Vanheule "); +MODULE_DESCRIPTION("regmap MDIO Module"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1