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/test/root-device-test.c | 112 +++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 drivers/base/test/root-device-test.c (limited to 'drivers/base/test/root-device-test.c') diff --git a/drivers/base/test/root-device-test.c b/drivers/base/test/root-device-test.c new file mode 100644 index 000000000..9aea23c91 --- /dev/null +++ b/drivers/base/test/root-device-test.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright 2023 Maxime Ripard + +#include + +#include + +#define DEVICE_NAME "test" + +struct test_priv { + bool probe_done; + bool release_done; + wait_queue_head_t release_wq; + struct device *dev; +}; + +static int root_device_devm_init(struct kunit *test) +{ + struct test_priv *priv; + + priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv); + init_waitqueue_head(&priv->release_wq); + + test->priv = priv; + + return 0; +} + +static void devm_device_action(void *ptr) +{ + struct test_priv *priv = ptr; + + priv->release_done = true; + wake_up_interruptible(&priv->release_wq); +} + +#define RELEASE_TIMEOUT_MS 100 + +/* + * Tests that a bus-less, non-probed device will run its device-managed + * actions when unregistered. + */ +static void root_device_devm_register_unregister_test(struct kunit *test) +{ + struct test_priv *priv = test->priv; + int ret; + + priv->dev = root_device_register(DEVICE_NAME); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev); + + ret = devm_add_action_or_reset(priv->dev, devm_device_action, priv); + KUNIT_ASSERT_EQ(test, ret, 0); + + root_device_unregister(priv->dev); + + ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done, + msecs_to_jiffies(RELEASE_TIMEOUT_MS)); + KUNIT_EXPECT_GT(test, ret, 0); +} + +static void devm_put_device_action(void *ptr) +{ + struct test_priv *priv = ptr; + + put_device(priv->dev); + priv->release_done = true; + wake_up_interruptible(&priv->release_wq); +} + +/* + * Tests that a bus-less, non-probed device will run its device-managed + * actions when unregistered, even if someone still holds a reference to + * it. + */ +static void root_device_devm_register_get_unregister_with_devm_test(struct kunit *test) +{ + struct test_priv *priv = test->priv; + int ret; + + priv->dev = root_device_register(DEVICE_NAME); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev); + + get_device(priv->dev); + + ret = devm_add_action_or_reset(priv->dev, devm_put_device_action, priv); + KUNIT_ASSERT_EQ(test, ret, 0); + + root_device_unregister(priv->dev); + + ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done, + msecs_to_jiffies(RELEASE_TIMEOUT_MS)); + KUNIT_EXPECT_GT(test, ret, 0); +} + +static struct kunit_case root_device_devm_tests[] = { + KUNIT_CASE(root_device_devm_register_unregister_test), + KUNIT_CASE(root_device_devm_register_get_unregister_with_devm_test), + {} +}; + +static struct kunit_suite root_device_devm_test_suite = { + .name = "root-device-devm", + .init = root_device_devm_init, + .test_cases = root_device_devm_tests, +}; + +kunit_test_suite(root_device_devm_test_suite); + +MODULE_DESCRIPTION("Test module for root devices"); +MODULE_AUTHOR("Maxime Ripard "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1