diff options
| -rw-r--r-- | Documentation/admin-guide/device-mapper/verity.rst | 11 | ||||
| -rw-r--r-- | drivers/md/dm-verity-target.c | 29 |
2 files changed, 35 insertions, 5 deletions
diff --git a/Documentation/admin-guide/device-mapper/verity.rst b/Documentation/admin-guide/device-mapper/verity.rst index fb3a045d0c72..8c3f1f967a3c 100644 --- a/Documentation/admin-guide/device-mapper/verity.rst +++ b/Documentation/admin-guide/device-mapper/verity.rst @@ -151,8 +151,15 @@ root_hash_sig_key_desc <key_description> already in the secondary trusted keyring. try_verify_in_tasklet - If verity hashes are in cache, verify data blocks in kernel tasklet instead - of workqueue. This option can reduce IO latency. + If verity hashes are in cache and the IO size does not exceed the limit, + verify data blocks in bottom half instead of workqueue. This option can + reduce IO latency. The size limits can be configured via + /sys/module/dm_verity/parameters/use_bh_bytes. The four parameters + correspond to limits for IOPRIO_CLASS_NONE, IOPRIO_CLASS_RT, + IOPRIO_CLASS_BE and IOPRIO_CLASS_IDLE in turn. + For example: + <none>,<rt>,<be>,<idle> + 4096,4096,4096,4096 Theory of operation =================== diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index fc5ae123670b..40448a8c74b1 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -30,6 +30,7 @@ #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 +#define DM_VERITY_USE_BH_DEFAULT_BYTES 8192 #define DM_VERITY_MAX_CORRUPTED_ERRS 100 @@ -49,6 +50,15 @@ static unsigned int dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, 0644); +static unsigned int dm_verity_use_bh_bytes[4] = { + DM_VERITY_USE_BH_DEFAULT_BYTES, // IOPRIO_CLASS_NONE + DM_VERITY_USE_BH_DEFAULT_BYTES, // IOPRIO_CLASS_RT + DM_VERITY_USE_BH_DEFAULT_BYTES, // IOPRIO_CLASS_BE + 0 // IOPRIO_CLASS_IDLE +}; + +module_param_array_named(use_bh_bytes, dm_verity_use_bh_bytes, uint, NULL, 0644); + static DEFINE_STATIC_KEY_FALSE(use_bh_wq_enabled); /* Is at least one dm-verity instance using ahash_tfm instead of shash_tfm? */ @@ -669,9 +679,17 @@ static void verity_bh_work(struct work_struct *w) verity_finish_io(io, errno_to_blk_status(err)); } +static inline bool verity_use_bh(unsigned int bytes, unsigned short ioprio) +{ + return ioprio <= IOPRIO_CLASS_IDLE && + bytes <= READ_ONCE(dm_verity_use_bh_bytes[ioprio]); +} + static void verity_end_io(struct bio *bio) { struct dm_verity_io *io = bio->bi_private; + unsigned short ioprio = IOPRIO_PRIO_CLASS(bio->bi_ioprio); + unsigned int bytes = io->n_blocks << io->v->data_dev_block_bits; if (bio->bi_status && (!verity_fec_is_enabled(io->v) || @@ -681,9 +699,14 @@ static void verity_end_io(struct bio *bio) return; } - if (static_branch_unlikely(&use_bh_wq_enabled) && io->v->use_bh_wq) { - INIT_WORK(&io->bh_work, verity_bh_work); - queue_work(system_bh_wq, &io->bh_work); + if (static_branch_unlikely(&use_bh_wq_enabled) && io->v->use_bh_wq && + verity_use_bh(bytes, ioprio)) { + if (in_hardirq() || irqs_disabled()) { + INIT_WORK(&io->bh_work, verity_bh_work); + queue_work(system_bh_wq, &io->bh_work); + } else { + verity_bh_work(&io->bh_work); + } } else { INIT_WORK(&io->work, verity_work); queue_work(io->v->verify_wq, &io->work); |