Maxim Patlasov <[email protected]> writes:
> The patch moves the logic of allocating new page for cbt->map[idx] to > a separate function. It will be used in further patches. ACK > > Signed-off-by: Maxim Patlasov <[email protected]> > --- > block/blk-cbt.c | 98 > +++++++++++++++++++++++++++++++++++-------------------- > 1 file changed, 62 insertions(+), 36 deletions(-) > > diff --git a/block/blk-cbt.c b/block/blk-cbt.c > index b66f513..08cefd8 100644 > --- a/block/blk-cbt.c > +++ b/block/blk-cbt.c > @@ -76,6 +76,61 @@ static void set_bits(void *bm, int cur, int len, bool > is_set) > } > } > > +/* > + * Return values: > + * 0 if OK, > + * -EAGAIN if cbt was updated, > + * -EBADF if cbt is dead, > + * -ENOMEM if alloc_page failed. > + */ > +static int cbt_page_alloc(struct cbt_info **cbt_pp, unsigned long idx, > + int in_rcu) > +{ > + struct cbt_info *cbt = *cbt_pp; > + struct page *page; > + > + /* Page not allocated yet. Synchronization required */ > + spin_lock_irq(&cbt->lock); > + if (likely(!test_bit(CBT_DEAD, &cbt->flags))) { > + cbt->count++; > + } else { > + struct cbt_info *new = rcu_dereference(cbt->queue->cbt); > + > + spin_unlock_irq(&cbt->lock); > + /* was cbt updated ? */ > + if (new != cbt) { > + *cbt_pp = new; > + return -EAGAIN; > + } else { > + return -EBADF; > + } > + } > + spin_unlock_irq(&cbt->lock); > + if (in_rcu) > + rcu_read_unlock(); > + page = alloc_page(GFP_NOIO|__GFP_ZERO); > + if (in_rcu) > + rcu_read_lock(); > + spin_lock_irq(&cbt->lock); > + if (unlikely(!cbt->count-- && test_bit(CBT_DEAD, &cbt->flags))) { > + spin_unlock_irq(&cbt->lock); > + call_rcu(&cbt->rcu, &cbt_release_callback); > + if (page) > + __free_page(page); > + return -EBADF; > + } > + if (unlikely(!page)) { > + set_bit(CBT_ERROR, &cbt->flags); > + spin_unlock_irq(&cbt->lock); > + return -ENOMEM; > + } > + cbt->map[idx] = page; > + page = NULL; > + spin_unlock_irq(&cbt->lock); > + > + return 0; > +} > + > static int __blk_cbt_set(struct cbt_info *cbt, blkcnt_t block, > blkcnt_t count, bool in_rcu, bool set) > { > @@ -95,6 +150,7 @@ static int __blk_cbt_set(struct cbt_info *cbt, blkcnt_t > block, > unsigned long off = block & (BITS_PER_PAGE -1); > unsigned long len = min_t(unsigned long, BITS_PER_PAGE - off, > count); > + int ret; > > page = cbt->map[idx]; > if (page) { > @@ -112,44 +168,14 @@ static int __blk_cbt_set(struct cbt_info *cbt, > blkcnt_t block, > continue; > } > } > - /* Page not allocated yet. Synchronization required */ > - spin_lock_irq(&cbt->lock); > - if (likely(!test_bit(CBT_DEAD, &cbt->flags))) { > - cbt->count++; > - } else { > - struct cbt_info *new = rcu_dereference(cbt->queue->cbt); > > - spin_unlock_irq(&cbt->lock); > - /* was cbt updated ? */ > - if (new != cbt) { > - cbt = new; > - continue; > - } else { > - break; > - } > - } > - spin_unlock_irq(&cbt->lock); > - if (in_rcu) > - rcu_read_unlock(); > - page = alloc_page(GFP_NOIO|__GFP_ZERO); > - if (in_rcu) > - rcu_read_lock(); > - spin_lock_irq(&cbt->lock); > - if (unlikely(!cbt->count-- && test_bit(CBT_DEAD, &cbt->flags))) > { > - spin_unlock_irq(&cbt->lock); > - call_rcu(&cbt->rcu, &cbt_release_callback); > - if (page) > - __free_page(page); > + ret = cbt_page_alloc(&cbt, idx, in_rcu); > + if (ret == -EAGAIN) /* new cbt */ > + continue; > + else if (ret == -EBADF) /* dead cbt */ > break; > - } > - if (unlikely(!page)) { > - set_bit(CBT_ERROR, &cbt->flags); > - spin_unlock_irq(&cbt->lock); > - return -ENOMEM; > - } > - cbt->map[idx] = page; > - page = NULL; > - spin_unlock_irq(&cbt->lock); > + else if (ret) > + return ret; > } > return 0; > }
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