From 551eb598e5ea52996eb821f43740496a78a97b68 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 2 Jun 2017 14:21:53 -0700 Subject: [PATCH] scsi: Split scsi_internal_device_block() Instead of passing a "wait" argument to scsi_internal_device_block(), split this function into a function that waits and a function that doesn't wait. This will make it easier to serialize SCSI device state changes through a mutex. Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Cc: Sreekanth Reddy Signed-off-by: Martin K. Petersen --- drivers/scsi/mpt3sas/mpt3sas_scsih.c | 4 +- drivers/scsi/scsi_lib.c | 73 ++++++++++++++++++---------- include/scsi/scsi_device.h | 2 +- 3 files changed, 50 insertions(+), 29 deletions(-) diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c index a5d872664257..c63bc5ccce37 100644 --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c @@ -2859,7 +2859,7 @@ _scsih_internal_device_block(struct scsi_device *sdev, sas_device_priv_data->sas_target->handle); sas_device_priv_data->block = 1; - r = scsi_internal_device_block(sdev, false); + r = scsi_internal_device_block_nowait(sdev); if (r == -EINVAL) sdev_printk(KERN_WARNING, sdev, "device_block failed with return(%d) for handle(0x%04x)\n", @@ -2895,7 +2895,7 @@ _scsih_internal_device_unblock(struct scsi_device *sdev, "performing a block followed by an unblock\n", r, sas_device_priv_data->sas_target->handle); sas_device_priv_data->block = 1; - r = scsi_internal_device_block(sdev, false); + r = scsi_internal_device_block_nowait(sdev); if (r) sdev_printk(KERN_WARNING, sdev, "retried device_block " "failed with return(%d) for handle(0x%04x)\n", diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index a95eb022fb89..fc8f394eb854 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2944,28 +2944,20 @@ scsi_target_resume(struct scsi_target *starget) EXPORT_SYMBOL(scsi_target_resume); /** - * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state - * @sdev: device to block - * @wait: Whether or not to wait until ongoing .queuecommand() / - * .queue_rq() calls have finished. + * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state + * @sdev: device to block * - * Block request made by scsi lld's to temporarily stop all - * scsi commands on the specified device. May sleep. + * Pause SCSI command processing on the specified device. Does not sleep. * - * Returns zero if successful or error if not + * Returns zero if successful or a negative error code upon failure. * - * Notes: - * This routine transitions the device to the SDEV_BLOCK state - * (which must be a legal transition). When the device is in this - * state, all commands are deferred until the scsi lld reenables - * the device with scsi_device_unblock or device_block_tmo fires. - * - * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after - * scsi_internal_device_block() has blocked a SCSI device and also - * remove the rport mutex lock and unlock calls from srp_queuecommand(). + * Notes: + * This routine transitions the device to the SDEV_BLOCK state (which must be + * a legal transition). When the device is in this state, command processing + * is paused until the device leaves the SDEV_BLOCK state. See also + * scsi_internal_device_unblock_nowait(). */ -int -scsi_internal_device_block(struct scsi_device *sdev, bool wait) +int scsi_internal_device_block_nowait(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; unsigned long flags; @@ -2985,21 +2977,50 @@ scsi_internal_device_block(struct scsi_device *sdev, bool wait) * request queue. */ if (q->mq_ops) { - if (wait) - blk_mq_quiesce_queue(q); - else - blk_mq_stop_hw_queues(q); + blk_mq_stop_hw_queues(q); } else { spin_lock_irqsave(q->queue_lock, flags); blk_stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); - if (wait) - scsi_wait_for_queuecommand(sdev); } return 0; } -EXPORT_SYMBOL_GPL(scsi_internal_device_block); +EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); + +/** + * scsi_internal_device_block - try to transition to the SDEV_BLOCK state + * @sdev: device to block + * + * Pause SCSI command processing on the specified device and wait until all + * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep. + * + * Returns zero if successful or a negative error code upon failure. + * + * Note: + * This routine transitions the device to the SDEV_BLOCK state (which must be + * a legal transition). When the device is in this state, command processing + * is paused until the device leaves the SDEV_BLOCK state. See also + * scsi_internal_device_unblock(). + * + * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after + * scsi_internal_device_block() has blocked a SCSI device and also + * remove the rport mutex lock and unlock calls from srp_queuecommand(). + */ +static int scsi_internal_device_block(struct scsi_device *sdev) +{ + struct request_queue *q = sdev->request_queue; + int err; + + err = scsi_internal_device_block_nowait(sdev); + if (err == 0) { + if (q->mq_ops) + blk_mq_quiesce_queue(q); + else + scsi_wait_for_queuecommand(sdev); + } + return err; +} /** * scsi_internal_device_unblock - resume a device after a block request @@ -3056,7 +3077,7 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); static void device_block(struct scsi_device *sdev, void *data) { - scsi_internal_device_block(sdev, true); + scsi_internal_device_block(sdev); } static int diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 05641aebd181..6ce6888f3c69 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -472,7 +472,7 @@ static inline int scsi_device_created(struct scsi_device *sdev) sdev->sdev_state == SDEV_CREATED_BLOCK; } -int scsi_internal_device_block(struct scsi_device *sdev, bool wait); +int scsi_internal_device_block_nowait(struct scsi_device *sdev); int scsi_internal_device_unblock(struct scsi_device *sdev, enum scsi_device_state new_state); -- 2.20.1