diff options
| author | Marco Elver <elver@google.com> | 2025-12-19 16:40:24 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-01-05 16:43:36 +0100 |
| commit | dc36d55d4e7259ff0f91a154744125ccc2228171 (patch) | |
| tree | 58b1ff6d120adf795e405027de8ce770233ade9a /crypto/scompress.c | |
| parent | 87335b61a23bd10e4aec132bd3a48a009d406973 (diff) | |
crypto: Enable context analysis
Enable context analysis for crypto subsystem.
This demonstrates a larger conversion to use Clang's context
analysis. The benefit is additional static checking of locking rules,
along with better documentation.
Note the use of the __acquire_ret macro how to define an API where a
function returns a pointer to an object (struct scomp_scratch) with a
lock held. Additionally, the analysis only resolves aliases where the
analysis unambiguously sees that a variable was not reassigned after
initialization, requiring minor code changes.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-36-elver@google.com
Diffstat (limited to 'crypto/scompress.c')
| -rw-r--r-- | crypto/scompress.c | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/crypto/scompress.c b/crypto/scompress.c index 1a7ed8ae65b0..7aee1d50e148 100644 --- a/crypto/scompress.c +++ b/crypto/scompress.c @@ -28,8 +28,8 @@ struct scomp_scratch { spinlock_t lock; union { - void *src; - unsigned long saddr; + void *src __guarded_by(&lock); + unsigned long saddr __guarded_by(&lock); }; }; @@ -38,8 +38,8 @@ static DEFINE_PER_CPU(struct scomp_scratch, scomp_scratch) = { }; static const struct crypto_type crypto_scomp_type; -static int scomp_scratch_users; static DEFINE_MUTEX(scomp_lock); +static int scomp_scratch_users __guarded_by(&scomp_lock); static cpumask_t scomp_scratch_want; static void scomp_scratch_workfn(struct work_struct *work); @@ -67,6 +67,7 @@ static void crypto_scomp_show(struct seq_file *m, struct crypto_alg *alg) } static void crypto_scomp_free_scratches(void) + __context_unsafe(/* frees @scratch */) { struct scomp_scratch *scratch; int i; @@ -101,7 +102,7 @@ static void scomp_scratch_workfn(struct work_struct *work) struct scomp_scratch *scratch; scratch = per_cpu_ptr(&scomp_scratch, cpu); - if (scratch->src) + if (context_unsafe(scratch->src)) continue; if (scomp_alloc_scratch(scratch, cpu)) break; @@ -111,6 +112,7 @@ static void scomp_scratch_workfn(struct work_struct *work) } static int crypto_scomp_alloc_scratches(void) + __context_unsafe(/* allocates @scratch */) { unsigned int i = cpumask_first(cpu_possible_mask); struct scomp_scratch *scratch; @@ -139,7 +141,8 @@ unlock: return ret; } -static struct scomp_scratch *scomp_lock_scratch(void) __acquires(scratch) +#define scomp_lock_scratch(...) __acquire_ret(_scomp_lock_scratch(__VA_ARGS__), &__ret->lock) +static struct scomp_scratch *_scomp_lock_scratch(void) __acquires_ret { int cpu = raw_smp_processor_id(); struct scomp_scratch *scratch; @@ -159,7 +162,7 @@ static struct scomp_scratch *scomp_lock_scratch(void) __acquires(scratch) } static inline void scomp_unlock_scratch(struct scomp_scratch *scratch) - __releases(scratch) + __releases(&scratch->lock) { spin_unlock(&scratch->lock); } @@ -171,8 +174,6 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir) bool src_isvirt = acomp_request_src_isvirt(req); bool dst_isvirt = acomp_request_dst_isvirt(req); struct crypto_scomp *scomp = *tfm_ctx; - struct crypto_acomp_stream *stream; - struct scomp_scratch *scratch; unsigned int slen = req->slen; unsigned int dlen = req->dlen; struct page *spage, *dpage; @@ -232,13 +233,12 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir) } while (0); } - stream = crypto_acomp_lock_stream_bh(&crypto_scomp_alg(scomp)->streams); + struct crypto_acomp_stream *stream = crypto_acomp_lock_stream_bh(&crypto_scomp_alg(scomp)->streams); if (!src_isvirt && !src) { - const u8 *src; + struct scomp_scratch *scratch = scomp_lock_scratch(); + const u8 *src = scratch->src; - scratch = scomp_lock_scratch(); - src = scratch->src; memcpy_from_sglist(scratch->src, req->src, 0, slen); if (dir) |