zcomp::stream is per-CPU pointer, pointing to struct zcomp_strm which contains two pointer. Having struct zcomp_strm allocated directly as per-CPU memory would avoid one additional memory allocation and a pointer dereference. This also also simplifies adding a local_lock to struct zcomp_strm.
Allocate zcomp::stream directly as per-CPU memory. Cc: Minchan Kim <[email protected]> Cc: Nitin Gupta <[email protected]> Cc: Sergey Senozhatsky <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- drivers/block/zram/zcomp.c | 34 ++++++++++++++-------------------- drivers/block/zram/zcomp.h | 2 +- 2 files changed, 15 insertions(+), 21 deletions(-) diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 1a8564a79d8dc..ae6dc137a1ed8 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -37,19 +37,17 @@ static void zcomp_strm_free(struct zcomp_strm *zstrm) if (!IS_ERR_OR_NULL(zstrm->tfm)) crypto_free_comp(zstrm->tfm); free_pages((unsigned long)zstrm->buffer, 1); - kfree(zstrm); + zstrm->tfm = NULL; + zstrm->buffer = NULL; } /* * allocate new zcomp_strm structure with ->tfm initialized by * backend, return NULL on error */ -static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) +static int zcomp_strm_alloc(struct zcomp_strm *zstrm, + struct zcomp *comp) { - struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL); - if (!zstrm) - return NULL; - zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0); /* * allocate 2 pages. 1 for compressed data, plus 1 extra for the @@ -58,9 +56,9 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) { zcomp_strm_free(zstrm); - zstrm = NULL; + return -ENOMEM; } - return zstrm; + return 0; } bool zcomp_available_algorithm(const char *comp) @@ -113,7 +111,7 @@ ssize_t zcomp_available_show(const char *comp, char *buf) struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) { - return *get_cpu_ptr(comp->stream); + return get_cpu_ptr(comp->stream); } void zcomp_stream_put(struct zcomp *comp) @@ -159,16 +157,14 @@ int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) { struct zcomp *comp = hlist_entry(node, struct zcomp, node); struct zcomp_strm *zstrm; + int ret; - if (WARN_ON(*per_cpu_ptr(comp->stream, cpu))) - return 0; - - zstrm = zcomp_strm_alloc(comp); - if (IS_ERR_OR_NULL(zstrm)) { + zstrm = per_cpu_ptr(comp->stream, cpu); + ret = zcomp_strm_alloc(zstrm, comp); + if (ret) { pr_err("Can't allocate a compression stream\n"); return -ENOMEM; } - *per_cpu_ptr(comp->stream, cpu) = zstrm; return 0; } @@ -177,10 +173,8 @@ int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node) struct zcomp *comp = hlist_entry(node, struct zcomp, node); struct zcomp_strm *zstrm; - zstrm = *per_cpu_ptr(comp->stream, cpu); - if (!IS_ERR_OR_NULL(zstrm)) - zcomp_strm_free(zstrm); - *per_cpu_ptr(comp->stream, cpu) = NULL; + zstrm = per_cpu_ptr(comp->stream, cpu); + zcomp_strm_free(zstrm); return 0; } @@ -188,7 +182,7 @@ static int zcomp_init(struct zcomp *comp) { int ret; - comp->stream = alloc_percpu(struct zcomp_strm *); + comp->stream = alloc_percpu(struct zcomp_strm); if (!comp->stream) return -ENOMEM; diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index 1806475b919df..72c2ee4d843ed 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -14,7 +14,7 @@ struct zcomp_strm { /* dynamic per-device compression frontend */ struct zcomp { - struct zcomp_strm * __percpu *stream; + struct zcomp_strm __percpu *stream; const char *name; struct hlist_node node; }; -- 2.27.0.rc0
