The patch adds two new args to __blk_cbt_set: pages_missed and idx_first. Both are pointers. No logic changed, so far as everybody passes NULL/NULL. The next patch will pass non-trivial values.
The idea is to mark slots in cbt->map[idx] that need allocation with special flag, save their number in *pages_missed and the first index of such a slot in *idx_first. This will be used by next patch. Signed-off-by: Maxim Patlasov <[email protected]> --- block/blk-cbt.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/block/blk-cbt.c b/block/blk-cbt.c index ee225a4..f83eb96 100644 --- a/block/blk-cbt.c +++ b/block/blk-cbt.c @@ -136,7 +136,9 @@ static int cbt_page_alloc(struct cbt_info **cbt_pp, unsigned long idx, } static int __blk_cbt_set(struct cbt_info *cbt, blkcnt_t block, - blkcnt_t count, bool in_rcu, bool set) + blkcnt_t count, bool in_rcu, bool set, + unsigned long *pages_missed, + unsigned long *idx_first) { struct page *page; @@ -164,7 +166,15 @@ static int __blk_cbt_set(struct cbt_info *cbt, blkcnt_t block, count -= len; block += len; continue; - } else { + } else if (pages_missed) { + (*pages_missed)++; + if (!*idx_first) + *idx_first = idx; + cbt->map[idx] = CBT_PAGE_MISSED; + count -= len; + block += len; + continue; + } else { if (!set) { /* Nothing to do */ count -= len; @@ -181,7 +191,7 @@ static int __blk_cbt_set(struct cbt_info *cbt, blkcnt_t block, else if (ret) return ret; } - return 0; + return (pages_missed && *pages_missed) ? -EAGAIN : 0; } static void blk_cbt_add(struct request_queue *q, blkcnt_t start, blkcnt_t len) @@ -203,7 +213,7 @@ static void blk_cbt_add(struct request_queue *q, blkcnt_t start, blkcnt_t len) start >>= cbt->block_bits; len = end - start; if (unlikely(test_bit(CBT_NOCACHE, &cbt->flags))) { - __blk_cbt_set(cbt, start, len, 1, 1); + __blk_cbt_set(cbt, start, len, 1, 1, NULL, NULL); goto out_rcu; } ex = this_cpu_ptr(cbt->cache); @@ -216,7 +226,7 @@ static void blk_cbt_add(struct request_queue *q, blkcnt_t start, blkcnt_t len) ex->len = len; if (likely(old.len)) - __blk_cbt_set(cbt, old.start, old.len, 1, 1); + __blk_cbt_set(cbt, old.start, old.len, 1, 1, NULL, NULL); out_rcu: rcu_read_unlock(); } @@ -401,7 +411,7 @@ static inline void __cbt_flush_cpu_cache(void *ptr) struct cbt_extent *ex = this_cpu_ptr(cbt->cache); if (ex->len) { - __blk_cbt_set(cbt, ex->start, ex->len, 0, 1); + __blk_cbt_set(cbt, ex->start, ex->len, 0, 1, NULL, NULL); ex->start += ex->len; ex->len = 0; } @@ -522,7 +532,7 @@ static int cbt_ioc_get(struct block_device *bdev, struct blk_user_cbt_info __use break; } if (ci.ci_flags & CI_FLAG_ONCE) - __blk_cbt_set(cbt, ex.start, ex.len, 0, 0); + __blk_cbt_set(cbt, ex.start, ex.len, 0, 0, NULL, NULL); cur_u_ex++; ci.ci_mapped_extents++; block = ex.start + ex.len; @@ -592,7 +602,7 @@ static int cbt_ioc_set(struct block_device *bdev, struct blk_user_cbt_info __use ret = -EINVAL; break; } - ret = __blk_cbt_set(cbt, ex.start, ex.len, 0, set); + ret = __blk_cbt_set(cbt, ex.start, ex.len, 0, set, NULL, NULL); if (ret) break; cur_u_ex++; _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
