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/of/overlay_test.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 drivers/of/overlay_test.c (limited to 'drivers/of/overlay_test.c') diff --git a/drivers/of/overlay_test.c b/drivers/of/overlay_test.c new file mode 100644 index 000000000..c787524c5 --- /dev/null +++ b/drivers/of/overlay_test.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit tests for device tree overlays + */ +#include +#include +#include +#include +#include + +#include +#include + +#include "of_private.h" + +static const char * const kunit_node_name = "kunit-test"; +static const char * const kunit_compatible = "test,empty"; + +/* Test that of_overlay_apply_kunit() adds a node to the live tree */ +static void of_overlay_apply_kunit_apply(struct kunit *test) +{ + struct device_node *np; + + KUNIT_ASSERT_EQ(test, 0, + of_overlay_apply_kunit(test, kunit_overlay_test)); + + np = of_find_node_by_name(NULL, kunit_node_name); + KUNIT_EXPECT_NOT_ERR_OR_NULL(test, np); + of_node_put(np); +} + +/* + * Test that of_overlay_apply_kunit() creates platform devices with the + * expected device_node + */ +static void of_overlay_apply_kunit_platform_device(struct kunit *test) +{ + struct platform_device *pdev; + struct device_node *np; + + KUNIT_ASSERT_EQ(test, 0, + of_overlay_apply_kunit(test, kunit_overlay_test)); + + np = of_find_node_by_name(NULL, kunit_node_name); + of_node_put_kunit(test, np); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np); + + pdev = of_find_device_by_node(np); + KUNIT_EXPECT_NOT_ERR_OR_NULL(test, pdev); + if (pdev) + put_device(&pdev->dev); +} + +static int of_overlay_bus_match_compatible(struct device *dev, const void *data) +{ + return of_device_is_compatible(dev->of_node, data); +} + +/* Test that of_overlay_apply_kunit() cleans up after the test is finished */ +static void of_overlay_apply_kunit_cleanup(struct kunit *test) +{ + struct kunit fake; + struct platform_device *pdev; + struct device *dev; + struct device_node *np; + + of_root_kunit_skip(test); + if (!IS_ENABLED(CONFIG_OF_OVERLAY)) + kunit_skip(test, "requires CONFIG_OF_OVERLAY to apply overlay"); + if (!IS_ENABLED(CONFIG_OF_EARLY_FLATTREE)) + kunit_skip(test, "requires CONFIG_OF_EARLY_FLATTREE for root node"); + + kunit_init_test(&fake, "fake test", NULL); + KUNIT_ASSERT_EQ(test, fake.status, KUNIT_SUCCESS); + + KUNIT_ASSERT_EQ(test, 0, + of_overlay_apply_kunit(&fake, kunit_overlay_test)); + + np = of_find_node_by_name(NULL, kunit_node_name); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np); + of_node_put_kunit(&fake, np); + + pdev = of_find_device_by_node(np); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev); + put_device(&pdev->dev); /* Not derefing 'pdev' after this */ + + /* Remove overlay */ + kunit_cleanup(&fake); + + /* The node and device should be removed */ + np = of_find_node_by_name(NULL, kunit_node_name); + KUNIT_EXPECT_PTR_EQ(test, NULL, np); + of_node_put(np); + + dev = bus_find_device(&platform_bus_type, NULL, kunit_compatible, + of_overlay_bus_match_compatible); + KUNIT_EXPECT_PTR_EQ(test, NULL, dev); + put_device(dev); +} + +static struct kunit_case of_overlay_apply_kunit_test_cases[] = { + KUNIT_CASE(of_overlay_apply_kunit_apply), + KUNIT_CASE(of_overlay_apply_kunit_platform_device), + KUNIT_CASE(of_overlay_apply_kunit_cleanup), + {} +}; + +/* + * Test suite for test managed device tree overlays. + */ +static struct kunit_suite of_overlay_apply_kunit_suite = { + .name = "of_overlay_apply_kunit", + .test_cases = of_overlay_apply_kunit_test_cases, +}; + +kunit_test_suites( + &of_overlay_apply_kunit_suite, +); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("KUnit tests for device tree overlays"); -- cgit v1.3.1