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AJvYcCVWa5b2w0GJoLtO2ebouK28NOruoA/kPO8aYNhHGrHYjh9uleP3Lqjequk8TszHx1FRC3Ur32UlWA==@kvack.org X-Gm-Message-State: AOJu0YwElBDRO9K3GphDuCvyseG8LH2ghdtyXENd5IFY9U66JuMeXaIn oKjcZRjEd9vTEHGUoFV+G1j/gTWMkMhN9te+gVCj+TWVMYbeTMt+qOTh5K0hBe+vBYu2OPmZRFT lLQ== X-Google-Smtp-Source: AGHT+IEl4ZXzZa5pPyzTXDxPRSH8PuS/I6bpKT2fhAEsb0xYuFK9NMlUOzOSp0EdHvBpo/b42AdwcHR6bBY= X-Received: from pjtu11.prod.google.com ([2002:a17:90a:c88b:b0:2f2:e933:8ba6]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:528a:b0:2ee:8619:210b with SMTP id 98e67ed59e1d1-2f452ec3589mr35645319a91.29.1735232856007; Thu, 26 Dec 2024 09:07:36 -0800 (PST) Date: Thu, 26 Dec 2024 09:07:03 -0800 In-Reply-To: <20241226170710.1159679-1-surenb@google.com> Mime-Version: 1.0 References: <20241226170710.1159679-1-surenb@google.com> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog Message-ID: <20241226170710.1159679-12-surenb@google.com> Subject: [PATCH v7 11/17] refcount: introduce __refcount_{add|inc}_not_zero_limited From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: peterz@infradead.org, willy@infradead.org, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, lokeshgidra@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, klarasmodin@gmail.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com X-Rspamd-Queue-Id: 388D8A000D X-Stat-Signature: r9fgnp44q7otuoe5t3za6jzfftppne4y X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1735232826-305322 X-HE-Meta: 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 H5jo8UYD 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Introduce functions to increase refcount but with a top limit above which they will fail to increase. Setting the limit to 0 indicates no limit. Signed-off-by: Suren Baghdasaryan --- include/linux/refcount.h | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/include/linux/refcount.h b/include/linux/refcount.h index 35f039ecb272..e51a49179307 100644 --- a/include/linux/refcount.h +++ b/include/linux/refcount.h @@ -137,13 +137,19 @@ static inline unsigned int refcount_read(const refcount_t *r) } static inline __must_check __signed_wrap -bool __refcount_add_not_zero(int i, refcount_t *r, int *oldp) +bool __refcount_add_not_zero_limited(int i, refcount_t *r, int *oldp, + int limit) { int old = refcount_read(r); do { if (!old) break; + if (limit && old + i > limit) { + if (oldp) + *oldp = old; + return false; + } } while (!atomic_try_cmpxchg_relaxed(&r->refs, &old, old + i)); if (oldp) @@ -155,6 +161,12 @@ bool __refcount_add_not_zero(int i, refcount_t *r, int *oldp) return old; } +static inline __must_check __signed_wrap +bool __refcount_add_not_zero(int i, refcount_t *r, int *oldp) +{ + return __refcount_add_not_zero_limited(i, r, oldp, 0); +} + /** * refcount_add_not_zero - add a value to a refcount unless it is 0 * @i: the value to add to the refcount @@ -213,6 +225,12 @@ static inline void refcount_add(int i, refcount_t *r) __refcount_add(i, r, NULL); } +static inline __must_check bool __refcount_inc_not_zero_limited(refcount_t *r, + int *oldp, int limit) +{ + return __refcount_add_not_zero_limited(1, r, oldp, limit); +} + static inline __must_check bool __refcount_inc_not_zero(refcount_t *r, int *oldp) { return __refcount_add_not_zero(1, r, oldp);