drbd: Fixed inc_ap_bio()
The condition must be checked after perpare_to_wait(). The old implementaion could loose wakeup events. Never observed in real life. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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127b317844
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8869d683b7
1 changed files with 14 additions and 17 deletions
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@ -2309,15 +2309,21 @@ static inline int __inc_ap_bio_cond(struct drbd_conf *mdev)
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return 1;
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}
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/* I'd like to use wait_event_lock_irq,
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* but I'm not sure when it got introduced,
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* and not sure when it has 3 or 4 arguments */
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static inline int _inc_ap_bio_cond(struct drbd_conf *mdev, int count)
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{
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int rv = 0;
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spin_lock_irq(&mdev->req_lock);
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rv = __inc_ap_bio_cond(mdev);
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if (rv)
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atomic_add(count, &mdev->ap_bio_cnt);
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spin_unlock_irq(&mdev->req_lock);
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return rv;
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}
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static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
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{
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/* compare with after_state_ch,
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* os.conn != C_WF_BITMAP_S && ns.conn == C_WF_BITMAP_S */
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DEFINE_WAIT(wait);
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/* we wait here
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* as long as the device is suspended
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* until the bitmap is no longer on the fly during connection
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@ -2326,16 +2332,7 @@ static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
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* to avoid races with the reconnect code,
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* we need to atomic_inc within the spinlock. */
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spin_lock_irq(&mdev->req_lock);
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while (!__inc_ap_bio_cond(mdev)) {
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prepare_to_wait(&mdev->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
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spin_unlock_irq(&mdev->req_lock);
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schedule();
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finish_wait(&mdev->misc_wait, &wait);
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spin_lock_irq(&mdev->req_lock);
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}
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atomic_add(count, &mdev->ap_bio_cnt);
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spin_unlock_irq(&mdev->req_lock);
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wait_event(mdev->misc_wait, _inc_ap_bio_cond(mdev, count));
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}
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static inline void dec_ap_bio(struct drbd_conf *mdev)
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