Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
selftests: revocable: Add kselftest cases
Add kselftest cases for the revocable API.
The test consists of three parts:
- A kernel module (revocable_test.ko) that creates a debugfs interface
with `/provider` and `/consumer` files.
- A user-space C program (revocable_test) that uses the kselftest
harness to interact with the debugfs files.
- An orchestrating shell script (test-revocable.sh) that loads the
module, runs the C program, and unloads the module.
The test cases cover the following scenarios:
- Basic: Verifies that a consumer can successfully access the resource
provided via the provider.
- Revocation: Verifies that after the provider revokes the resource,
the consumer correctly receives a NULL pointer on a subsequent access.
- Try Access Macro: Same as "Revocation" but uses the
REVOCABLE_TRY_ACCESS_WITH() and REVOCABLE_TRY_ACCESS_SCOPED().
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://patch.msgid.link/20260116080235.350305-4-tzungbi@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
authored by
Tzung-Bi Shih
and committed by
Greg Kroah-Hartman
9d4502fe
cd769341
+389
+1
MAINTAINERS
+1
MAINTAINERS
+1
tools/testing/selftests/Makefile
+1
tools/testing/selftests/Makefile
+7
tools/testing/selftests/drivers/base/revocable/Makefile
+7
tools/testing/selftests/drivers/base/revocable/Makefile
+136
tools/testing/selftests/drivers/base/revocable/revocable_test.c
+136
tools/testing/selftests/drivers/base/revocable/revocable_test.c
···
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2026 Google LLC
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*
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* A selftest for the revocable API.
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*
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* The test cases cover the following scenarios:
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*
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* - Basic: Verifies that a consumer can successfully access the resource
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* provided via the provider.
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*
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* - Revocation: Verifies that after the provider revokes the resource,
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* the consumer correctly receives a NULL pointer on a subsequent access.
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*
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* - Try Access Macro: Same as "Revocation" but uses the
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* REVOCABLE_TRY_ACCESS_WITH() and REVOCABLE_TRY_ACCESS_SCOPED().
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*/
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#include <fcntl.h>
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#include <unistd.h>
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#include "../../../kselftest_harness.h"
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#define DEBUGFS_PATH "/sys/kernel/debug/revocable_test"
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#define TEST_CMD_RESOURCE_GONE "resource_gone"
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#define TEST_DATA "12345678"
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#define TEST_MAGIC_OFFSET 0x1234
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#define TEST_MAGIC_OFFSET2 0x5678
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FIXTURE(revocable_fixture) {
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int pfd;
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int cfd;
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};
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FIXTURE_SETUP(revocable_fixture) {
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int ret;
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self->pfd = open(DEBUGFS_PATH "/provider", O_WRONLY);
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ASSERT_NE(-1, self->pfd)
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TH_LOG("failed to open provider fd");
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ret = write(self->pfd, TEST_DATA, strlen(TEST_DATA));
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ASSERT_NE(-1, ret) {
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close(self->pfd);
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TH_LOG("failed to write test data");
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}
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self->cfd = open(DEBUGFS_PATH "/consumer", O_RDONLY);
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ASSERT_NE(-1, self->cfd)
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TH_LOG("failed to open consumer fd");
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}
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FIXTURE_TEARDOWN(revocable_fixture) {
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close(self->cfd);
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close(self->pfd);
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}
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/*
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* ASSERT_* is only available in TEST or TEST_F block. Use
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* macro for the helper.
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*/
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#define READ_TEST_DATA(_fd, _offset, _data, _msg) \
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do { \
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int ret; \
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\
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ret = lseek(_fd, _offset, SEEK_SET); \
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ASSERT_NE(-1, ret) \
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TH_LOG("failed to lseek"); \
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\
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ret = read(_fd, _data, sizeof(_data) - 1); \
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ASSERT_NE(-1, ret) \
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TH_LOG(_msg); \
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data[ret] = '\0'; \
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} while (0)
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TEST_F(revocable_fixture, basic) {
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char data[16];
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READ_TEST_DATA(self->cfd, 0, data, "failed to read test data");
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EXPECT_STREQ(TEST_DATA, data);
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}
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TEST_F(revocable_fixture, revocation) {
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char data[16];
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int ret;
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READ_TEST_DATA(self->cfd, 0, data, "failed to read test data");
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EXPECT_STREQ(TEST_DATA, data);
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ret = write(self->pfd, TEST_CMD_RESOURCE_GONE,
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strlen(TEST_CMD_RESOURCE_GONE));
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ASSERT_NE(-1, ret)
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TH_LOG("failed to write resource gone cmd");
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READ_TEST_DATA(self->cfd, 0, data,
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"failed to read test data after resource gone");
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EXPECT_STREQ("(null)", data);
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}
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TEST_F(revocable_fixture, try_access_macro) {
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char data[16];
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int ret;
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READ_TEST_DATA(self->cfd, TEST_MAGIC_OFFSET, data,
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"failed to read test data");
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EXPECT_STREQ(TEST_DATA, data);
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ret = write(self->pfd, TEST_CMD_RESOURCE_GONE,
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strlen(TEST_CMD_RESOURCE_GONE));
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ASSERT_NE(-1, ret)
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TH_LOG("failed to write resource gone cmd");
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READ_TEST_DATA(self->cfd, TEST_MAGIC_OFFSET, data,
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"failed to read test data after resource gone");
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EXPECT_STREQ("(null)", data);
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}
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TEST_F(revocable_fixture, try_access_macro2) {
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char data[16];
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int ret;
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READ_TEST_DATA(self->cfd, TEST_MAGIC_OFFSET2, data,
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"failed to read test data");
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EXPECT_STREQ(TEST_DATA, data);
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ret = write(self->pfd, TEST_CMD_RESOURCE_GONE,
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strlen(TEST_CMD_RESOURCE_GONE));
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ASSERT_NE(-1, ret)
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TH_LOG("failed to write resource gone cmd");
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READ_TEST_DATA(self->cfd, TEST_MAGIC_OFFSET2, data,
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"failed to read test data after resource gone");
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EXPECT_STREQ("(null)", data);
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}
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TEST_HARNESS_MAIN
+39
tools/testing/selftests/drivers/base/revocable/test-revocable.sh
+39
tools/testing/selftests/drivers/base/revocable/test-revocable.sh
···
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#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0
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mod_name="revocable_test"
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ksft_fail=1
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ksft_skip=4
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if [ "$(id -u)" -ne 0 ]; then
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echo "$0: Must be run as root"
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exit "$ksft_skip"
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fi
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if ! which insmod > /dev/null 2>&1; then
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echo "$0: Need insmod"
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exit "$ksft_skip"
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fi
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if ! which rmmod > /dev/null 2>&1; then
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echo "$0: Need rmmod"
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exit "$ksft_skip"
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fi
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insmod test_modules/"${mod_name}".ko
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if [ ! -d /sys/kernel/debug/revocable_test/ ]; then
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mount -t debugfs none /sys/kernel/debug/
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if [ ! -d /sys/kernel/debug/revocable_test/ ]; then
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echo "$0: Error mounting debugfs"
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exit "$ksft_fail"
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fi
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fi
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./revocable_test
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ret=$?
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rmmod "${mod_name}"
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exit "${ret}"
+10
tools/testing/selftests/drivers/base/revocable/test_modules/Makefile
+10
tools/testing/selftests/drivers/base/revocable/test_modules/Makefile
+195
tools/testing/selftests/drivers/base/revocable/test_modules/revocable_test.c
+195
tools/testing/selftests/drivers/base/revocable/test_modules/revocable_test.c
···
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2026 Google LLC
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*
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* A kernel module for testing the revocable API.
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*/
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#include <linux/debugfs.h>
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#include <linux/module.h>
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#include <linux/revocable.h>
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#include <linux/slab.h>
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#define TEST_CMD_RESOURCE_GONE "resource_gone"
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#define TEST_MAGIC_OFFSET 0x1234
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#define TEST_MAGIC_OFFSET2 0x5678
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static struct dentry *debugfs_dir;
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struct revocable_test_provider_priv {
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struct revocable_provider *rp;
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struct dentry *dentry;
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char res[16];
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};
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static int revocable_test_consumer_open(struct inode *inode, struct file *filp)
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{
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struct revocable *rev;
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struct revocable_provider *rp = inode->i_private;
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rev = revocable_alloc(rp);
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if (!rev)
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return -ENOMEM;
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filp->private_data = rev;
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return 0;
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}
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static int revocable_test_consumer_release(struct inode *inode,
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struct file *filp)
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{
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struct revocable *rev = filp->private_data;
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revocable_free(rev);
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return 0;
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}
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static ssize_t revocable_test_consumer_read(struct file *filp,
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char __user *buf,
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size_t count, loff_t *offset)
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{
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char *res;
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char data[16];
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size_t len;
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struct revocable *rev = filp->private_data;
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switch (*offset) {
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case 0:
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res = revocable_try_access(rev);
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snprintf(data, sizeof(data), "%s", res ?: "(null)");
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revocable_withdraw_access(rev);
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break;
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case TEST_MAGIC_OFFSET:
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{
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REVOCABLE_TRY_ACCESS_WITH(rev, res);
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snprintf(data, sizeof(data), "%s", res ?: "(null)");
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}
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break;
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case TEST_MAGIC_OFFSET2:
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REVOCABLE_TRY_ACCESS_SCOPED(rev, res)
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snprintf(data, sizeof(data), "%s", res ?: "(null)");
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break;
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default:
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return 0;
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}
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len = min_t(size_t, strlen(data), count);
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if (copy_to_user(buf, data, len))
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return -EFAULT;
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*offset = len;
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return len;
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}
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static const struct file_operations revocable_test_consumer_fops = {
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.open = revocable_test_consumer_open,
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.release = revocable_test_consumer_release,
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.read = revocable_test_consumer_read,
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.llseek = default_llseek,
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};
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static int revocable_test_provider_open(struct inode *inode, struct file *filp)
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{
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struct revocable_test_provider_priv *priv;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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filp->private_data = priv;
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return 0;
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}
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static int revocable_test_provider_release(struct inode *inode,
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struct file *filp)
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{
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struct revocable_test_provider_priv *priv = filp->private_data;
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debugfs_remove(priv->dentry);
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if (priv->rp)
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revocable_provider_revoke(priv->rp);
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kfree(priv);
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return 0;
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}
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static ssize_t revocable_test_provider_write(struct file *filp,
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const char __user *buf,
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size_t count, loff_t *offset)
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{
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size_t copied;
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char data[64];
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struct revocable_test_provider_priv *priv = filp->private_data;
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copied = strncpy_from_user(data, buf, sizeof(data));
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if (copied < 0)
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return copied;
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if (copied == sizeof(data))
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data[sizeof(data) - 1] = '\0';
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/*
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* Note: The test can't just close the FD for signaling the
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* resource gone. Subsequent file operations on the opening
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* FD of debugfs return -EIO after calling debugfs_remove().
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* See also debugfs_file_get().
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*
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* Here is a side command channel for signaling the resource
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* gone.
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*/
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if (!strcmp(data, TEST_CMD_RESOURCE_GONE)) {
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revocable_provider_revoke(priv->rp);
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priv->rp = NULL;
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} else {
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if (priv->res[0] != '\0')
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return 0;
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strscpy(priv->res, data);
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priv->rp = revocable_provider_alloc(&priv->res);
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if (!priv->rp)
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return -ENOMEM;
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priv->dentry = debugfs_create_file("consumer", 0400,
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debugfs_dir, priv->rp,
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&revocable_test_consumer_fops);
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if (!priv->dentry) {
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revocable_provider_revoke(priv->rp);
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return -ENOMEM;
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}
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}
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return copied;
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}
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static const struct file_operations revocable_test_provider_fops = {
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.open = revocable_test_provider_open,
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.release = revocable_test_provider_release,
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.write = revocable_test_provider_write,
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};
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static int __init revocable_test_init(void)
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{
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debugfs_dir = debugfs_create_dir("revocable_test", NULL);
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if (!debugfs_dir)
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return -ENOMEM;
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if (!debugfs_create_file("provider", 0200, debugfs_dir, NULL,
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&revocable_test_provider_fops)) {
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debugfs_remove_recursive(debugfs_dir);
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return -ENOMEM;
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}
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return 0;
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}
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static void __exit revocable_test_exit(void)
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{
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debugfs_remove_recursive(debugfs_dir);
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}
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module_init(revocable_test_init);
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module_exit(revocable_test_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Tzung-Bi Shih <tzungbi@kernel.org>");
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MODULE_DESCRIPTION("Revocable Kselftest");