diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/iov_iter.c | 77 | ||||
| -rw-r--r-- | lib/rhashtable.c | 27 |
2 files changed, 92 insertions, 12 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 7e43cd54c84c..8be175df3075 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -596,15 +596,70 @@ static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset, return ret; } +static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes, + struct iov_iter *i) +{ + struct pipe_inode_info *pipe = i->pipe; + size_t n, off, xfer = 0; + int idx; + + if (!sanity(i)) + return 0; + + bytes = n = push_pipe(i, bytes, &idx, &off); + if (unlikely(!n)) + return 0; + for ( ; n; idx = next_idx(idx, pipe), off = 0) { + size_t chunk = min_t(size_t, n, PAGE_SIZE - off); + unsigned long rem; + + rem = memcpy_mcsafe_to_page(pipe->bufs[idx].page, off, addr, + chunk); + i->idx = idx; + i->iov_offset = off + chunk - rem; + xfer += chunk - rem; + if (rem) + break; + n -= chunk; + addr += chunk; + } + i->count -= xfer; + return xfer; +} + +/** + * _copy_to_iter_mcsafe - copy to user with source-read error exception handling + * @addr: source kernel address + * @bytes: total transfer length + * @iter: destination iterator + * + * The pmem driver arranges for filesystem-dax to use this facility via + * dax_copy_to_iter() for protecting read/write to persistent memory. + * Unless / until an architecture can guarantee identical performance + * between _copy_to_iter_mcsafe() and _copy_to_iter() it would be a + * performance regression to switch more users to the mcsafe version. + * + * Otherwise, the main differences between this and typical _copy_to_iter(). + * + * * Typical tail/residue handling after a fault retries the copy + * byte-by-byte until the fault happens again. Re-triggering machine + * checks is potentially fatal so the implementation uses source + * alignment and poison alignment assumptions to avoid re-triggering + * hardware exceptions. + * + * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. + * Compare to copy_to_iter() where only ITER_IOVEC attempts might return + * a short copy. + * + * See MCSAFE_TEST for self-test. + */ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i) { const char *from = addr; unsigned long rem, curr_addr, s_addr = (unsigned long) addr; - if (unlikely(i->type & ITER_PIPE)) { - WARN_ON(1); - return 0; - } + if (unlikely(i->type & ITER_PIPE)) + return copy_pipe_to_iter_mcsafe(addr, bytes, i); if (iter_is_iovec(i)) might_fault(); iterate_and_advance(i, bytes, v, @@ -701,6 +756,20 @@ size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) EXPORT_SYMBOL(_copy_from_iter_nocache); #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE +/** + * _copy_from_iter_flushcache - write destination through cpu cache + * @addr: destination kernel address + * @bytes: total transfer length + * @iter: source iterator + * + * The pmem driver arranges for filesystem-dax to use this facility via + * dax_copy_from_iter() for ensuring that writes to persistent memory + * are flushed through the CPU cache. It is differentiated from + * _copy_from_iter_nocache() in that guarantees all data is flushed for + * all iterator types. The _copy_from_iter_nocache() only attempts to + * bypass the cache for the ITER_IOVEC case, and on some archs may use + * instructions that strand dirty-data in the cache. + */ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) { char *to = addr; diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 9427b5766134..e5c8586cf717 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -774,7 +774,7 @@ int rhashtable_walk_start_check(struct rhashtable_iter *iter) skip++; if (list == iter->list) { iter->p = p; - skip = skip; + iter->skip = skip; goto found; } } @@ -964,8 +964,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_stop); static size_t rounded_hashtable_size(const struct rhashtable_params *params) { - return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), - (unsigned long)params->min_size); + size_t retsize; + + if (params->nelem_hint) + retsize = max(roundup_pow_of_two(params->nelem_hint * 4 / 3), + (unsigned long)params->min_size); + else + retsize = max(HASH_DEFAULT_SIZE, + (unsigned long)params->min_size); + + return retsize; } static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) @@ -1022,8 +1030,6 @@ int rhashtable_init(struct rhashtable *ht, struct bucket_table *tbl; size_t size; - size = HASH_DEFAULT_SIZE; - if ((!params->key_len && !params->obj_hashfn) || (params->obj_hashfn && !params->obj_cmpfn)) return -EINVAL; @@ -1050,8 +1056,7 @@ int rhashtable_init(struct rhashtable *ht, ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); - if (params->nelem_hint) - size = rounded_hashtable_size(&ht->p); + size = rounded_hashtable_size(&ht->p); if (params->locks_mul) ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); @@ -1143,13 +1148,14 @@ void rhashtable_free_and_destroy(struct rhashtable *ht, void (*free_fn)(void *ptr, void *arg), void *arg) { - struct bucket_table *tbl; + struct bucket_table *tbl, *next_tbl; unsigned int i; cancel_work_sync(&ht->run_work); mutex_lock(&ht->mutex); tbl = rht_dereference(ht->tbl, ht); +restart: if (free_fn) { for (i = 0; i < tbl->size; i++) { struct rhash_head *pos, *next; @@ -1166,7 +1172,12 @@ void rhashtable_free_and_destroy(struct rhashtable *ht, } } + next_tbl = rht_dereference(tbl->future_tbl, ht); bucket_table_free(tbl); + if (next_tbl) { + tbl = next_tbl; + goto restart; + } mutex_unlock(&ht->mutex); } EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); |