On Wed, Sep 09, 2015 at 03:02:11PM +0800, Ken Xue wrote:
> From 844ebfcecad7ddaf7206e0474c600b0146b4ef21 Mon Sep 17 00:00:00 2001
> From: Ken Xue <Ken.Xue@xxxxxxx>
> Date: Wed, 9 Sep 2015 14:55:21 +0800
> Subject: [PATCH] SCSI:Refine the way to fix NULL pointer dereference in
> runtime PM
>
> There was a patch about Bugzilla #101371.
Which Bugzilla? I guess you should put a link or oops message of NULL
pointer dereference here. Then other guys can know detail infomation
of this fix.
Thanks,
Rui
> That patch introduced a possibility that can not call
> blk_{pre|post}_runtime_suspend and blk_{pre|post}_runtime_resume in
> pairs.
>
> Signed-off-by: Ken Xue <Ken.Xue@xxxxxxx>
> ---
> block/blk-core.c | 12 ++++++++++++
> drivers/scsi/scsi_pm.c | 20 ++++++++++----------
> 2 files changed, 22 insertions(+), 10 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 60912e9..a07ab18 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -3280,6 +3280,9 @@ int blk_pre_runtime_suspend(struct request_queue *q)
> {
> int ret = 0;
>
> + if (!q->dev)
> + return ret;
> +
> spin_lock_irq(q->queue_lock);
> if (q->nr_pending) {
> ret = -EBUSY;
> @@ -3307,6 +3310,9 @@ EXPORT_SYMBOL(blk_pre_runtime_suspend);
> */
> void blk_post_runtime_suspend(struct request_queue *q, int err)
> {
> + if (!q->dev)
> + return;
> +
> spin_lock_irq(q->queue_lock);
> if (!err) {
> q->rpm_status = RPM_SUSPENDED;
> @@ -3331,6 +3337,9 @@ EXPORT_SYMBOL(blk_post_runtime_suspend);
> */
> void blk_pre_runtime_resume(struct request_queue *q)
> {
> + if (!q->dev)
> + return;
> +
> spin_lock_irq(q->queue_lock);
> q->rpm_status = RPM_RESUMING;
> spin_unlock_irq(q->queue_lock);
> @@ -3353,6 +3362,9 @@ EXPORT_SYMBOL(blk_pre_runtime_resume);
> */
> void blk_post_runtime_resume(struct request_queue *q, int err)
> {
> + if (!q->dev)
> + return;
> +
> spin_lock_irq(q->queue_lock);
> if (!err) {
> q->rpm_status = RPM_ACTIVE;
> diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
> index e4b7998..459abe1 100644
> --- a/drivers/scsi/scsi_pm.c
> +++ b/drivers/scsi/scsi_pm.c
> @@ -219,13 +219,13 @@ static int sdev_runtime_suspend(struct device *dev)
> struct scsi_device *sdev = to_scsi_device(dev);
> int err = 0;
>
> - if (pm && pm->runtime_suspend) {
> - err = blk_pre_runtime_suspend(sdev->request_queue);
> - if (err)
> - return err;
> + err = blk_pre_runtime_suspend(sdev->request_queue);
> + if (err)
> + return err;
> + if (pm && pm->runtime_suspend)
> err = pm->runtime_suspend(dev);
> - blk_post_runtime_suspend(sdev->request_queue, err);
> - }
> + blk_post_runtime_suspend(sdev->request_queue, err);
> +
> return err;
> }
>
> @@ -248,11 +248,11 @@ static int sdev_runtime_resume(struct device *dev)
> const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> int err = 0;
>
> - if (pm && pm->runtime_resume) {
> - blk_pre_runtime_resume(sdev->request_queue);
> + blk_pre_runtime_resume(sdev->request_queue);
> + if (pm && pm->runtime_resume)
> err = pm->runtime_resume(dev);
> - blk_post_runtime_resume(sdev->request_queue, err);
> - }
> + blk_post_runtime_resume(sdev->request_queue, err);
> +
> return err;
> }
>
> --
> 1.9.1
>
>
>
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