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Mon, 01 Dec 2025 01:48:21 -0800 (PST) Received: from tigerii.tok.corp.google.com ([2a00:79e0:2031:6:943c:f651:f00f:2459]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7d15e7db577sm12882074b3a.31.2025.12.01.01.48.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Dec 2025 01:48:21 -0800 (PST) From: Sergey Senozhatsky To: Andrew Morton , Richard Chang , Minchan Kim Cc: Brian Geffon , David Stevens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, Sergey Senozhatsky Subject: [PATCHv2 6/7] zram: switch to guard() for init_lock Date: Mon, 1 Dec 2025 18:47:53 +0900 Message-ID: <20251201094754.4149975-7-senozhatsky@chromium.org> X-Mailer: git-send-email 2.52.0.487.g5c8c507ade-goog In-Reply-To: <20251201094754.4149975-1-senozhatsky@chromium.org> References: <20251201094754.4149975-1-senozhatsky@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use init_lock guard() in sysfs store/show handlers, in order to simplify and, more importantly, to modernize the code. While at it, fix up more coding styles. Signed-off-by: Sergey Senozhatsky --- drivers/block/zram/zram_drv.c | 211 +++++++++++++--------------------- 1 file changed, 77 insertions(+), 134 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 615756d5d05d..4b8a26c60539 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -360,15 +360,14 @@ static bool page_same_filled(void *ptr, unsigned long= *element) return true; } =20 -static ssize_t initstate_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t initstate_show(struct device *dev, struct device_attribute = *attr, + char *buf) { u32 val; struct zram *zram =3D dev_to_zram(dev); =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); val =3D init_done(zram); - up_read(&zram->init_lock); =20 return sysfs_emit(buf, "%u\n", val); } @@ -382,7 +381,8 @@ static ssize_t disksize_show(struct device *dev, } =20 static ssize_t mem_limit_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) + struct device_attribute *attr, const char *buf, + size_t len) { u64 limit; char *tmp; @@ -392,15 +392,15 @@ static ssize_t mem_limit_store(struct device *dev, if (buf =3D=3D tmp) /* no chars parsed, invalid input */ return -EINVAL; =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); zram->limit_pages =3D PAGE_ALIGN(limit) >> PAGE_SHIFT; - up_write(&zram->init_lock); =20 return len; } =20 static ssize_t mem_used_max_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) + struct device_attribute *attr, + const char *buf, size_t len) { int err; unsigned long val; @@ -410,12 +410,11 @@ static ssize_t mem_used_max_store(struct device *dev, if (err || val !=3D 0) return -EINVAL; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); if (init_done(zram)) { atomic_long_set(&zram->stats.max_used_pages, zs_get_total_pages(zram->mem_pool)); } - up_read(&zram->init_lock); =20 return len; } @@ -458,12 +457,11 @@ static void mark_idle(struct zram *zram, ktime_t cuto= ff) } } =20 -static ssize_t idle_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) +static ssize_t idle_store(struct device *dev, struct device_attribute *att= r, + const char *buf, size_t len) { struct zram *zram =3D dev_to_zram(dev); ktime_t cutoff_time =3D 0; - ssize_t rv =3D -EINVAL; =20 if (!sysfs_streq(buf, "all")) { /* @@ -476,24 +474,19 @@ static ssize_t idle_store(struct device *dev, cutoff_time =3D ktime_sub(ktime_get_boottime(), ns_to_ktime(age_sec * NSEC_PER_SEC)); else - goto out; + return -EINVAL; } =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); if (!init_done(zram)) - goto out_unlock; + return -EINVAL; =20 /* * A cutoff_time of 0 marks everything as idle, this is the * "all" behavior. */ mark_idle(zram, cutoff_time); - rv =3D len; - -out_unlock: - up_read(&zram->init_lock); -out: - return rv; + return len; } =20 #ifdef CONFIG_ZRAM_WRITEBACK @@ -546,13 +539,12 @@ static ssize_t bd_stat_show(struct device *dev, struc= t device_attribute *attr, struct zram *zram =3D dev_to_zram(dev); ssize_t ret; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); ret =3D sysfs_emit(buf, "%8llu %8llu %8llu\n", FOUR_K((u64)atomic64_read(&zram->stats.bd_count)), FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)), FOUR_K((u64)atomic64_read(&zram->stats.bd_writes))); - up_read(&zram->init_lock); =20 return ret; } @@ -567,14 +559,12 @@ static ssize_t writeback_compressed_store(struct devi= ce *dev, if (kstrtobool(buf, &val)) return -EINVAL; =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); if (init_done(zram)) { - up_write(&zram->init_lock); return -EBUSY; } =20 zram->wb_compressed =3D val; - up_write(&zram->init_lock); =20 return len; } @@ -586,9 +576,8 @@ static ssize_t writeback_compressed_show(struct device = *dev, bool val; struct zram *zram =3D dev_to_zram(dev); =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); val =3D zram->wb_compressed; - up_read(&zram->init_lock); =20 return sysfs_emit(buf, "%d\n", val); } @@ -599,17 +588,14 @@ static ssize_t writeback_limit_enable_store(struct de= vice *dev, { struct zram *zram =3D dev_to_zram(dev); u64 val; - ssize_t ret =3D -EINVAL; =20 if (kstrtoull(buf, 10, &val)) - return ret; + return -EINVAL; =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); zram->wb_limit_enable =3D val; - up_write(&zram->init_lock); - ret =3D len; =20 - return ret; + return len; } =20 static ssize_t writeback_limit_enable_show(struct device *dev, @@ -619,9 +605,8 @@ static ssize_t writeback_limit_enable_show(struct devic= e *dev, bool val; struct zram *zram =3D dev_to_zram(dev); =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); val =3D zram->wb_limit_enable; - up_read(&zram->init_lock); =20 return sysfs_emit(buf, "%d\n", val); } @@ -632,10 +617,9 @@ static ssize_t writeback_limit_store(struct device *de= v, { struct zram *zram =3D dev_to_zram(dev); u64 val; - ssize_t ret =3D -EINVAL; =20 if (kstrtoull(buf, 10, &val)) - return ret; + return -EINVAL; =20 /* * When the page size is greater than 4KB, if bd_wb_limit is set to @@ -647,12 +631,10 @@ static ssize_t writeback_limit_store(struct device *d= ev, */ val =3D rounddown(val, PAGE_SIZE / 4096); =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); zram->bd_wb_limit =3D val; - up_write(&zram->init_lock); - ret =3D len; =20 - return ret; + return len; } =20 static ssize_t writeback_limit_show(struct device *dev, @@ -661,9 +643,8 @@ static ssize_t writeback_limit_show(struct device *dev, u64 val; struct zram *zram =3D dev_to_zram(dev); =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); val =3D zram->bd_wb_limit; - up_read(&zram->init_lock); =20 return sysfs_emit(buf, "%llu\n", val); } @@ -681,9 +662,8 @@ static ssize_t writeback_batch_size_store(struct device= *dev, if (!val) return -EINVAL; =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); zram->wb_batch_size =3D val; - up_write(&zram->init_lock); =20 return len; } @@ -695,9 +675,8 @@ static ssize_t writeback_batch_size_show(struct device = *dev, u32 val; struct zram *zram =3D dev_to_zram(dev); =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); val =3D zram->wb_batch_size; - up_read(&zram->init_lock); =20 return sysfs_emit(buf, "%u\n", val); } @@ -717,37 +696,33 @@ static void reset_bdev(struct zram *zram) } =20 static ssize_t backing_dev_show(struct device *dev, - struct device_attribute *attr, char *buf) + struct device_attribute *attr, char *buf) { struct file *file; struct zram *zram =3D dev_to_zram(dev); char *p; ssize_t ret; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); file =3D zram->backing_dev; if (!file) { memcpy(buf, "none\n", 5); - up_read(&zram->init_lock); return 5; } =20 p =3D file_path(file, buf, PAGE_SIZE - 1); - if (IS_ERR(p)) { - ret =3D PTR_ERR(p); - goto out; - } + if (IS_ERR(p)) + return PTR_ERR(p); =20 ret =3D strlen(p); memmove(buf, p, ret); buf[ret++] =3D '\n'; -out: - up_read(&zram->init_lock); return ret; } =20 static ssize_t backing_dev_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) + struct device_attribute *attr, const char *buf, + size_t len) { char *file_name; size_t sz; @@ -762,7 +737,7 @@ static ssize_t backing_dev_store(struct device *dev, if (!file_name) return -ENOMEM; =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); if (init_done(zram)) { pr_info("Can't setup backing device for initialized device\n"); err =3D -EBUSY; @@ -810,7 +785,6 @@ static ssize_t backing_dev_store(struct device *dev, zram->backing_dev =3D backing_dev; zram->bitmap =3D bitmap; zram->nr_pages =3D nr_pages; - up_write(&zram->init_lock); =20 pr_info("setup backing device %s\n", file_name); kfree(file_name); @@ -822,8 +796,6 @@ static ssize_t backing_dev_store(struct device *dev, if (backing_dev) filp_close(backing_dev, NULL); =20 - up_write(&zram->init_lock); - kfree(file_name); =20 return err; @@ -1291,33 +1263,29 @@ static ssize_t writeback_store(struct device *dev, ssize_t ret =3D len; int err, mode =3D 0; =20 - down_read(&zram->init_lock); - if (!init_done(zram)) { - up_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); + if (!init_done(zram)) return -EINVAL; - } =20 /* Do not permit concurrent post-processing actions. */ - if (atomic_xchg(&zram->pp_in_progress, 1)) { - up_read(&zram->init_lock); + if (atomic_xchg(&zram->pp_in_progress, 1)) return -EAGAIN; - } =20 if (!zram->backing_dev) { ret =3D -ENODEV; - goto release_init_lock; + goto out; } =20 pp_ctl =3D init_pp_ctl(); if (!pp_ctl) { ret =3D -ENOMEM; - goto release_init_lock; + goto out; } =20 wb_ctl =3D init_wb_ctl(zram); if (!wb_ctl) { ret =3D -ENOMEM; - goto release_init_lock; + goto out; } =20 args =3D skip_spaces(buf); @@ -1341,7 +1309,7 @@ static ssize_t writeback_store(struct device *dev, err =3D parse_mode(param, &mode); if (err) { ret =3D err; - goto release_init_lock; + goto out; } =20 scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl); @@ -1352,7 +1320,7 @@ static ssize_t writeback_store(struct device *dev, err =3D parse_mode(val, &mode); if (err) { ret =3D err; - goto release_init_lock; + goto out; } =20 scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl); @@ -1363,7 +1331,7 @@ static ssize_t writeback_store(struct device *dev, err =3D parse_page_index(val, nr_pages, &lo, &hi); if (err) { ret =3D err; - goto release_init_lock; + goto out; } =20 scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl); @@ -1374,7 +1342,7 @@ static ssize_t writeback_store(struct device *dev, err =3D parse_page_indexes(val, nr_pages, &lo, &hi); if (err) { ret =3D err; - goto release_init_lock; + goto out; } =20 scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl); @@ -1386,11 +1354,10 @@ static ssize_t writeback_store(struct device *dev, if (err) ret =3D err; =20 -release_init_lock: +out: release_pp_ctl(zram, pp_ctl); release_wb_ctl(wb_ctl); atomic_set(&zram->pp_in_progress, 0); - up_read(&zram->init_lock); =20 return ret; } @@ -1608,9 +1575,8 @@ static ssize_t read_block_state(struct file *file, ch= ar __user *buf, if (!kbuf) return -ENOMEM; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); if (!init_done(zram)) { - up_read(&zram->init_lock); kvfree(kbuf); return -EINVAL; } @@ -1646,7 +1612,6 @@ static ssize_t read_block_state(struct file *file, ch= ar __user *buf, *ppos +=3D 1; } =20 - up_read(&zram->init_lock); if (copy_to_user(buf, kbuf, written)) written =3D -EFAULT; kvfree(kbuf); @@ -1713,16 +1678,14 @@ static int __comp_algorithm_store(struct zram *zram= , u32 prio, const char *buf) return -EINVAL; } =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); if (init_done(zram)) { - up_write(&zram->init_lock); kfree(compressor); pr_info("Can't change algorithm for initialized device\n"); return -EBUSY; } =20 comp_algorithm_set(zram, prio, compressor); - up_write(&zram->init_lock); return 0; } =20 @@ -1843,9 +1806,8 @@ static ssize_t comp_algorithm_show(struct device *dev, struct zram *zram =3D dev_to_zram(dev); ssize_t sz; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); sz =3D zcomp_available_show(zram->comp_algs[ZRAM_PRIMARY_COMP], buf, 0); - up_read(&zram->init_lock); return sz; } =20 @@ -1870,7 +1832,7 @@ static ssize_t recomp_algorithm_show(struct device *d= ev, ssize_t sz =3D 0; u32 prio; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); for (prio =3D ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) { if (!zram->comp_algs[prio]) continue; @@ -1878,7 +1840,6 @@ static ssize_t recomp_algorithm_show(struct device *d= ev, sz +=3D sysfs_emit_at(buf, sz, "#%d: ", prio); sz +=3D zcomp_available_show(zram->comp_algs[prio], buf, sz); } - up_read(&zram->init_lock); return sz; } =20 @@ -1924,42 +1885,38 @@ static ssize_t recomp_algorithm_store(struct device= *dev, } #endif =20 -static ssize_t compact_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) +static ssize_t compact_store(struct device *dev, struct device_attribute *= attr, + const char *buf, size_t len) { struct zram *zram =3D dev_to_zram(dev); =20 - down_read(&zram->init_lock); - if (!init_done(zram)) { - up_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); + if (!init_done(zram)) return -EINVAL; - } =20 zs_compact(zram->mem_pool); - up_read(&zram->init_lock); =20 return len; } =20 -static ssize_t io_stat_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t io_stat_show(struct device *dev, struct device_attribute *a= ttr, + char *buf) { struct zram *zram =3D dev_to_zram(dev); ssize_t ret; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); ret =3D sysfs_emit(buf, "%8llu %8llu 0 %8llu\n", (u64)atomic64_read(&zram->stats.failed_reads), (u64)atomic64_read(&zram->stats.failed_writes), (u64)atomic64_read(&zram->stats.notify_free)); - up_read(&zram->init_lock); =20 return ret; } =20 -static ssize_t mm_stat_show(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t mm_stat_show(struct device *dev, struct device_attribute *a= ttr, + char *buf) { struct zram *zram =3D dev_to_zram(dev); struct zs_pool_stats pool_stats; @@ -1969,7 +1926,7 @@ static ssize_t mm_stat_show(struct device *dev, =20 memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats)); =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); if (init_done(zram)) { mem_used =3D zs_get_total_pages(zram->mem_pool); zs_pool_stats(zram->mem_pool, &pool_stats); @@ -1989,7 +1946,6 @@ static ssize_t mm_stat_show(struct device *dev, atomic_long_read(&pool_stats.pages_compacted), (u64)atomic64_read(&zram->stats.huge_pages), (u64)atomic64_read(&zram->stats.huge_pages_since)); - up_read(&zram->init_lock); =20 return ret; } @@ -2001,12 +1957,11 @@ static ssize_t debug_stat_show(struct device *dev, struct zram *zram =3D dev_to_zram(dev); ssize_t ret; =20 - down_read(&zram->init_lock); + guard(rwsem_read)(&zram->init_lock); ret =3D sysfs_emit(buf, "version: %d\n0 %8llu\n", version, (u64)atomic64_read(&zram->stats.miss_free)); - up_read(&zram->init_lock); =20 return ret; } @@ -2669,17 +2624,13 @@ static ssize_t recompress_store(struct device *dev, if (threshold >=3D huge_class_size) return -EINVAL; =20 - down_read(&zram->init_lock); - if (!init_done(zram)) { - ret =3D -EINVAL; - goto release_init_lock; - } + guard(rwsem_read)(&zram->init_lock); + if (!init_done(zram)) + return -EINVAL; =20 /* Do not permit concurrent post-processing actions. */ - if (atomic_xchg(&zram->pp_in_progress, 1)) { - up_read(&zram->init_lock); + if (atomic_xchg(&zram->pp_in_progress, 1)) return -EAGAIN; - } =20 if (algo) { bool found =3D false; @@ -2697,26 +2648,26 @@ static ssize_t recompress_store(struct device *dev, =20 if (!found) { ret =3D -EINVAL; - goto release_init_lock; + goto out; } } =20 prio_max =3D min(prio_max, (u32)zram->num_active_comps); if (prio >=3D prio_max) { ret =3D -EINVAL; - goto release_init_lock; + goto out; } =20 page =3D alloc_page(GFP_KERNEL); if (!page) { ret =3D -ENOMEM; - goto release_init_lock; + goto out; } =20 ctl =3D init_pp_ctl(); if (!ctl) { ret =3D -ENOMEM; - goto release_init_lock; + goto out; } =20 scan_slots_for_recompress(zram, mode, prio_max, ctl); @@ -2747,12 +2698,11 @@ static ssize_t recompress_store(struct device *dev, cond_resched(); } =20 -release_init_lock: +out: if (page) __free_page(page); release_pp_ctl(zram, ctl); atomic_set(&zram->pp_in_progress, 0); - up_read(&zram->init_lock); return ret; } #endif @@ -2931,7 +2881,7 @@ static void zram_destroy_comps(struct zram *zram) =20 static void zram_reset_device(struct zram *zram) { - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); =20 zram->limit_pages =3D 0; =20 @@ -2947,11 +2897,10 @@ static void zram_reset_device(struct zram *zram) reset_bdev(zram); =20 comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor); - up_write(&zram->init_lock); } =20 -static ssize_t disksize_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) +static ssize_t disksize_store(struct device *dev, struct device_attribute = *attr, + const char *buf, size_t len) { u64 disksize; struct zcomp *comp; @@ -2963,18 +2912,15 @@ static ssize_t disksize_store(struct device *dev, if (!disksize) return -EINVAL; =20 - down_write(&zram->init_lock); + guard(rwsem_write)(&zram->init_lock); if (init_done(zram)) { pr_info("Cannot change disksize for initialized device\n"); - err =3D -EBUSY; - goto out_unlock; + return -EBUSY; } =20 disksize =3D PAGE_ALIGN(disksize); - if (!zram_meta_alloc(zram, disksize)) { - err =3D -ENOMEM; - goto out_unlock; - } + if (!zram_meta_alloc(zram, disksize)) + return -ENOMEM; =20 for (prio =3D ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) { if (!zram->comp_algs[prio]) @@ -2994,15 +2940,12 @@ static ssize_t disksize_store(struct device *dev, } zram->disksize =3D disksize; set_capacity_and_notify(zram->disk, zram->disksize >> SECTOR_SHIFT); - up_write(&zram->init_lock); =20 return len; =20 out_free_comps: zram_destroy_comps(zram); zram_meta_free(zram, disksize); -out_unlock: - up_write(&zram->init_lock); return err; } =20 --=20 2.52.0.487.g5c8c507ade-goog