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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745811426; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=msMOLWNhdsitkHxfB8eybUZIVkvsiA7kEk7v+r38KUo=; b=GFoHq5dcQ1uvGTDy7BA4uNFas/fMqvlMu3PTWRSM5Xpm+2VVDbazr2X5JguDEvw4nzBsJN m3P7yw1F2qUugoTIVwS1rrY6sr8wbZiP0L4rPyw7+TYng0tBEI1wSGnIn1L49RE86nT0xA khTj52Zjw6SCGhFYo3s7wNtbwSdohYY= From: Roman Gushchin To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Alexei Starovoitov , Johannes Weiner , Michal Hocko , Shakeel Butt , Suren Baghdasaryan , David Rientjes , Josh Don , Chuyi Zhou , cgroups@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, Roman Gushchin Subject: [PATCH rfc 11/12] bpf: selftests: introduce open_cgroup_file() helper Date: Mon, 28 Apr 2025 03:36:16 +0000 Message-ID: <20250428033617.3797686-12-roman.gushchin@linux.dev> In-Reply-To: <20250428033617.3797686-1-roman.gushchin@linux.dev> References: <20250428033617.3797686-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9F6C810000B X-Stat-Signature: ric3iyj6utx63ceag8zi1mecrug7gfz6 X-Rspam-User: X-HE-Tag: 1745811427-301804 X-HE-Meta: U2FsdGVkX18PRsGiSHHljIXNZhJ1r5bV//0sub8b8a/JUXUl2AfAxZIN+Y4KkZ5/dr8glxWHUDL8F/ncdI7T/a9mufOepnq/Yr2ZprncZHT82+EHPnEVuvFceu+ktbHgW1qoDFM7cuu66SXB/T+ARMkclpKL7k7oC9PTaAwoTY7DBzwhleU1UF2wGqyRk9bnQ9fmn13BspdOAd5NBe8HNnc7QammGsl5pqStQ4YEP+BAgSnFvzsWcTOuj//VNSif3yGpn08RuoJUZZeH4X0WsayfIIo/7JEnq5C938n4z7lsYXvwOYT22aaPabS6kf5SYNJ7U76YnEYON+73WikLVb8giGUphr+SpaJDZfpx3Ew/6GWZ/Zxuvx00Ovdtz0CtvahprdaUwpSEyxWM/GKwvNQxsZV14xDFwWmdb0+uXBh4wvbiz1vDzI1O8zYK7T8QiodDvOAbeFABBu2D79cxelR4xDxoszbwgcYiZV1/p5U6n9Bx/SU/0YFmWGuAHPsvI+lmCg8eePlY1KDt82IH0G6FN10+7stE0c3wG+NGglnKJyH4YLm20oUmcsT4gh2bPCSTBj7+77+HPiSUv9jBmMPVcy7f4VelTTMLGnLu+UayFOst6wfoVlzNOQASzZ8Hi7ZG+cc0y5ByNnaMXjYXmF12wiNctuZh6LHgFQTrIGeW8CzjC7w1+Lf093vDYa5+Dvw6wFysEZKiaajDhumu9xPoQErpGmnVrLlXVZklAKrqSDNq0ktkAfl1rvHz+o4njyEZruPOPxWDHO131YgCv0DR/gyWQBvWCftwHU0ZQ0PKrjsOcnw24JUioFfBMCKNCPfm0lE1gDrLWkupMS3h1n9/iMn3nykDo4/8dSxu6lWnhC39J6BBskmLnyTJpj7U4rmKWyV6dpOIG3wBnTlneYJ9r2aqYuNxq3zfvbsRrjvngX5HjF8qLxZR0nK+Hcj9fwOnns8Wxg44Ze6VY+E 6GxnueqM oPJQHS6JjmISz6/RHOOLlCM1nGv/TdAvHtuGIRZ7iALL7+IZ8fJdEOqnooOSIYlP/KopRYIKRDy7Pn3dtCHMRsxW7tKpXxCcwbjxfyrlyOpx0+2YzStIoXTDO+u1W9bSXMqhaqvzSfm3BwqLJVBW3RHcmrJRGd5ZctByuG5/Kw5danoqD8+VeQgt95LGS1E2olLL8YlImRCPfmFlaKUDA86UbNb6++UnW0W5w X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Implement the open_cgroup_file() helper which opens a cgroup control file with the given flags and returns a file descriptor. It's useful when a test needs to do something more sophisticated than read/write, e.g. listen for poll events or keep the file descriptor open. Signed-off-by: Roman Gushchin --- tools/testing/selftests/bpf/cgroup_helpers.c | 28 ++++++++++++++++++++ tools/testing/selftests/bpf/cgroup_helpers.h | 1 + 2 files changed, 29 insertions(+) diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c index 3ffd4b764f91..50dbe4f45cb1 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -125,6 +125,34 @@ int enable_controllers(const char *relative_path, const char *controllers) return __enable_controllers(cgroup_path, controllers); } +static int __open_cgroup_file(const char *cgroup_path, const char *file, + int flags) +{ + char file_path[PATH_MAX + 1]; + + snprintf(file_path, sizeof(file_path), "%s/%s", cgroup_path, file); + return open(file_path, flags); +} + +/** + * open_cgroup_file() - Open a cgroup file + * @relative_path: The cgroup path, relative to the workdir + * @file: The name of the file in cgroupfs to open to + * @flags: Flags + * + * Open a file in the given cgroup's directory. + * + * If successful, fd is returned. + */ +int open_cgroup_file(const char *relative_path, const char *file, + int flags) +{ + char cgroup_path[PATH_MAX - 24]; + + format_cgroup_path(cgroup_path, relative_path); + return __open_cgroup_file(cgroup_path, file, flags); +} + static size_t __read_cgroup_file(const char *cgroup_path, const char *file, char *buf, size_t size) { diff --git a/tools/testing/selftests/bpf/cgroup_helpers.h b/tools/testing/selftests/bpf/cgroup_helpers.h index 821cb76db1f7..f45007d5fea5 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.h +++ b/tools/testing/selftests/bpf/cgroup_helpers.h @@ -11,6 +11,7 @@ /* cgroupv2 related */ int enable_controllers(const char *relative_path, const char *controllers); +int open_cgroup_file(const char *relative_path, const char *file, int flags); size_t read_cgroup_file(const char *relative_path, const char *file, char *buf, size_t size); int write_cgroup_file(const char *relative_path, const char *file, -- 2.49.0.901.g37484f566f-goog