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/auxiliary_sysfs.c | 113 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) create mode 100644 drivers/base/auxiliary_sysfs.c (limited to 'drivers/base/auxiliary_sysfs.c') diff --git a/drivers/base/auxiliary_sysfs.c b/drivers/base/auxiliary_sysfs.c new file mode 100644 index 000000000..dea7f46f7 --- /dev/null +++ b/drivers/base/auxiliary_sysfs.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES + */ + +#include +#include + +#define AUXILIARY_MAX_IRQ_NAME 11 + +struct auxiliary_irq_info { + struct device_attribute sysfs_attr; + char name[AUXILIARY_MAX_IRQ_NAME]; +}; + +static struct attribute *auxiliary_irq_attrs[] = { + NULL +}; + +static const struct attribute_group auxiliary_irqs_group = { + .name = "irqs", + .attrs = auxiliary_irq_attrs, +}; + +static int auxiliary_irq_dir_prepare(struct auxiliary_device *auxdev) +{ + int ret = 0; + + guard(mutex)(&auxdev->sysfs.lock); + if (auxdev->sysfs.irq_dir_exists) + return 0; + + ret = devm_device_add_group(&auxdev->dev, &auxiliary_irqs_group); + if (ret) + return ret; + + auxdev->sysfs.irq_dir_exists = true; + xa_init(&auxdev->sysfs.irqs); + return 0; +} + +/** + * auxiliary_device_sysfs_irq_add - add a sysfs entry for the given IRQ + * @auxdev: auxiliary bus device to add the sysfs entry. + * @irq: The associated interrupt number. + * + * This function should be called after auxiliary device have successfully + * received the irq. + * The driver is responsible to add a unique irq for the auxiliary device. The + * driver can invoke this function from multiple thread context safely for + * unique irqs of the auxiliary devices. The driver must not invoke this API + * multiple times if the irq is already added previously. + * + * Return: zero on success or an error code on failure. + */ +int auxiliary_device_sysfs_irq_add(struct auxiliary_device *auxdev, int irq) +{ + struct auxiliary_irq_info *info __free(kfree) = NULL; + struct device *dev = &auxdev->dev; + int ret; + + ret = auxiliary_irq_dir_prepare(auxdev); + if (ret) + return ret; + + info = kzalloc_obj(*info); + if (!info) + return -ENOMEM; + + sysfs_attr_init(&info->sysfs_attr.attr); + snprintf(info->name, AUXILIARY_MAX_IRQ_NAME, "%d", irq); + + ret = xa_insert(&auxdev->sysfs.irqs, irq, info, GFP_KERNEL); + if (ret) + return ret; + + info->sysfs_attr.attr.name = info->name; + ret = sysfs_add_file_to_group(&dev->kobj, &info->sysfs_attr.attr, + auxiliary_irqs_group.name); + if (ret) + goto sysfs_add_err; + + xa_store(&auxdev->sysfs.irqs, irq, no_free_ptr(info), GFP_KERNEL); + return 0; + +sysfs_add_err: + xa_erase(&auxdev->sysfs.irqs, irq); + return ret; +} +EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_add); + +/** + * auxiliary_device_sysfs_irq_remove - remove a sysfs entry for the given IRQ + * @auxdev: auxiliary bus device to add the sysfs entry. + * @irq: the IRQ to remove. + * + * This function should be called to remove an IRQ sysfs entry. + * The driver must invoke this API when IRQ is released by the device. + */ +void auxiliary_device_sysfs_irq_remove(struct auxiliary_device *auxdev, int irq) +{ + struct auxiliary_irq_info *info __free(kfree) = xa_load(&auxdev->sysfs.irqs, irq); + struct device *dev = &auxdev->dev; + + if (!info) { + dev_err(&auxdev->dev, "IRQ %d doesn't exist\n", irq); + return; + } + sysfs_remove_file_from_group(&dev->kobj, &info->sysfs_attr.attr, + auxiliary_irqs_group.name); + xa_erase(&auxdev->sysfs.irqs, irq); +} +EXPORT_SYMBOL_GPL(auxiliary_device_sysfs_irq_remove); -- cgit v1.3.1