| Message ID | 20230517222359.1066918-4-bvanassche@acm.org |
|---|---|
| State | New |
| Headers | show |
| Series | UFS host controller driver patches | expand |
On 18/05/23 01:23, Bart Van Assche wrote: > Prepare for adding code in ufshcd_queuecommand() that may sleep. > > Signed-off-by: Bart Van Assche <bvanassche@acm.org> > --- > drivers/ufs/core/ufshcd.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c > index 7ee150d67d49..993034ac1696 100644 > --- a/drivers/ufs/core/ufshcd.c > +++ b/drivers/ufs/core/ufshcd.c > @@ -8756,6 +8756,7 @@ static const struct scsi_host_template ufshcd_driver_template = { > .max_host_blocked = 1, > .track_queue_depth = 1, > .skip_settle_delay = 1, > + .queuecommand_may_block = true, Shouldn't this only be for controllers that support clock gating? > .sdev_groups = ufshcd_driver_groups, > .rpm_autosuspend_delay = RPM_AUTOSUSPEND_DELAY_MS, > }; >
On 5/23/23 09:39, Adrian Hunter wrote: > On 18/05/23 01:23, Bart Van Assche wrote: >> Prepare for adding code in ufshcd_queuecommand() that may sleep. >> >> Signed-off-by: Bart Van Assche <bvanassche@acm.org> >> --- >> drivers/ufs/core/ufshcd.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c >> index 7ee150d67d49..993034ac1696 100644 >> --- a/drivers/ufs/core/ufshcd.c >> +++ b/drivers/ufs/core/ufshcd.c >> @@ -8756,6 +8756,7 @@ static const struct scsi_host_template ufshcd_driver_template = { >> .max_host_blocked = 1, >> .track_queue_depth = 1, >> .skip_settle_delay = 1, >> + .queuecommand_may_block = true, > > Shouldn't this only be for controllers that support > clock gating? Hi Adrian, The overhead of BLK_MQ_F_BLOCKING is small relative to the time required to queue a UFS command so I think enabling BLK_MQ_F_BLOCKING for all UFS host controllers is fine. BLK_MQ_F_BLOCKING causes the block layer to use SRCU instead of RCU. The cost of the sleepable RCU primitives is dominated by the memory barrier (smp_mb()) in the srcu_read_lock() and srcu_read_unlock() calls. From kernel/rcu/srcutree.c: int __srcu_read_lock(struct srcu_struct *ssp) { int idx; idx = READ_ONCE(ssp->srcu_idx) & 0x1; this_cpu_inc(ssp->sda->srcu_lock_count[idx].counter); smp_mb(); /* B */ /* Avoid leaking the critical section. */ return idx; } EXPORT_SYMBOL_GPL(__srcu_read_lock); void __srcu_read_unlock(struct srcu_struct *ssp, int idx) { smp_mb(); /* C */ /* Avoid leaking the critical section. */ this_cpu_inc(ssp->sda->srcu_unlock_count[idx].counter); } EXPORT_SYMBOL_GPL(__srcu_read_unlock); The rcu_read_lock() and rcu_read_lock() implementations do not call smp_mb() as one can see in include/linux/rcupdate.h: static inline void __rcu_read_lock(void) { preempt_disable(); } static inline void __rcu_read_unlock(void) { preempt_enable(); if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) rcu_read_unlock_strict(); } Thanks, Bart.
On 23/05/23 20:10, Bart Van Assche wrote: > On 5/23/23 09:39, Adrian Hunter wrote: >> On 18/05/23 01:23, Bart Van Assche wrote: >>> Prepare for adding code in ufshcd_queuecommand() that may sleep. >>> >>> Signed-off-by: Bart Van Assche <bvanassche@acm.org> >>> --- >>> drivers/ufs/core/ufshcd.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c >>> index 7ee150d67d49..993034ac1696 100644 >>> --- a/drivers/ufs/core/ufshcd.c >>> +++ b/drivers/ufs/core/ufshcd.c >>> @@ -8756,6 +8756,7 @@ static const struct scsi_host_template ufshcd_driver_template = { >>> .max_host_blocked = 1, >>> .track_queue_depth = 1, >>> .skip_settle_delay = 1, >>> + .queuecommand_may_block = true, >> >> Shouldn't this only be for controllers that support >> clock gating? > > Hi Adrian, > > The overhead of BLK_MQ_F_BLOCKING is small relative to the time required to > queue a UFS command so I think enabling BLK_MQ_F_BLOCKING for all UFS host > controllers is fine. Doesn't it also force the queue to be run asynchronously always? But in any case, it doesn't seem like something to force on drivers just because it would take a bit more coding to make it optional. > BLK_MQ_F_BLOCKING causes the block layer to use SRCU > instead of RCU. The cost of the sleepable RCU primitives is dominated by > the memory barrier (smp_mb()) in the srcu_read_lock() and srcu_read_unlock() > calls. From kernel/rcu/srcutree.c: > > int __srcu_read_lock(struct srcu_struct *ssp) > { > int idx; > > idx = READ_ONCE(ssp->srcu_idx) & 0x1; > this_cpu_inc(ssp->sda->srcu_lock_count[idx].counter); > smp_mb(); /* B */ /* Avoid leaking the critical section. */ > return idx; > } > EXPORT_SYMBOL_GPL(__srcu_read_lock); > > void __srcu_read_unlock(struct srcu_struct *ssp, int idx) > { > smp_mb(); /* C */ /* Avoid leaking the critical section. */ > this_cpu_inc(ssp->sda->srcu_unlock_count[idx].counter); > } > EXPORT_SYMBOL_GPL(__srcu_read_unlock); > > The rcu_read_lock() and rcu_read_lock() implementations do not call > smp_mb() as one can see in include/linux/rcupdate.h: > > static inline void __rcu_read_lock(void) > { > preempt_disable(); > } > > static inline void __rcu_read_unlock(void) > { > preempt_enable(); > if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) > rcu_read_unlock_strict(); > } > > Thanks, > > Bart. >
On 5/23/23 12:19, Adrian Hunter wrote: > On 23/05/23 20:10, Bart Van Assche wrote: >> The overhead of BLK_MQ_F_BLOCKING is small relative to the time required to >> queue a UFS command so I think enabling BLK_MQ_F_BLOCKING for all UFS host >> controllers is fine. > > Doesn't it also force the queue to be run asynchronously always? > > But in any case, it doesn't seem like something to force on drivers > just because it would take a bit more coding to make it optional. Making BLK_MQ_F_BLOCKING optional would complicate testing of the UFS driver. Although it is possible to make BLK_MQ_F_BLOCKING optional, I'm wondering whether it is worth it? I haven't noticed any performance difference in my tests with BLK_MQ_F_BLOCKING enabled compared to BLK_MQ_F_BLOCKING disabled. Thanks, Bart.
On 23/05/23 22:57, Bart Van Assche wrote: > On 5/23/23 12:19, Adrian Hunter wrote: >> On 23/05/23 20:10, Bart Van Assche wrote: >>> The overhead of BLK_MQ_F_BLOCKING is small relative to the time required to >>> queue a UFS command so I think enabling BLK_MQ_F_BLOCKING for all UFS host >>> controllers is fine. >> >> Doesn't it also force the queue to be run asynchronously always? >> >> But in any case, it doesn't seem like something to force on drivers >> just because it would take a bit more coding to make it optional. > Making BLK_MQ_F_BLOCKING optional would complicate testing of the UFS driver. Although it is possible to make BLK_MQ_F_BLOCKING optional, I'm wondering whether it is worth it? I haven't noticed any performance difference in my tests with BLK_MQ_F_BLOCKING enabled compared to BLK_MQ_F_BLOCKING disabled. It is hard to know the effects, especially wrt to future hardware. What about something like this? diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 82321b8b32bc..301c0b2a406d 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10049,13 +10049,16 @@ static int ufshcd_set_dma_mask(struct ufs_hba *hba) } /** - * ufshcd_alloc_host - allocate Host Bus Adapter (HBA) + * __ufshcd_alloc_host - allocate Host Bus Adapter (HBA) * @dev: pointer to device handle * @hba_handle: driver private handle + * @vops: pointer to variant specific operations * Returns 0 on success, non-zero value on failure */ -int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) +int __ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle, + const struct ufs_hba_variant_ops *vops) { + struct scsi_host_template sht = ufshcd_driver_template; struct Scsi_Host *host; struct ufs_hba *hba; int err = 0; @@ -10067,8 +10070,10 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) goto out_error; } - host = scsi_host_alloc(&ufshcd_driver_template, - sizeof(struct ufs_hba)); + if (vops && vops->nonblocking) + sht.queuecommand_may_block = false; + + host = scsi_host_alloc(&sht, sizeof(struct ufs_hba)); if (!host) { dev_err(dev, "scsi_host_alloc failed\n"); err = -ENOMEM; @@ -10078,6 +10083,7 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) hba = shost_priv(host); hba->host = host; hba->dev = dev; + hba->vops = vops; hba->dev_ref_clk_freq = REF_CLK_FREQ_INVAL; hba->nop_out_timeout = NOP_OUT_TIMEOUT; ufshcd_set_sg_entry_size(hba, sizeof(struct ufshcd_sg_entry)); @@ -10089,7 +10095,7 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) out_error: return err; } -EXPORT_SYMBOL(ufshcd_alloc_host); +EXPORT_SYMBOL(__ufshcd_alloc_host); /* This function exists because blk_mq_alloc_tag_set() requires this. */ static blk_status_t ufshcd_queue_tmf(struct blk_mq_hw_ctx *hctx, diff --git a/drivers/ufs/host/ufshcd-pci.c b/drivers/ufs/host/ufshcd-pci.c index 9c911787f84c..ce42b822fcb6 100644 --- a/drivers/ufs/host/ufshcd-pci.c +++ b/drivers/ufs/host/ufshcd-pci.c @@ -447,6 +447,7 @@ static int ufs_intel_mtl_init(struct ufs_hba *hba) static struct ufs_hba_variant_ops ufs_intel_cnl_hba_vops = { .name = "intel-pci", + .nonblocking = true, .init = ufs_intel_common_init, .exit = ufs_intel_common_exit, .link_startup_notify = ufs_intel_link_startup_notify, @@ -455,6 +456,7 @@ static struct ufs_hba_variant_ops ufs_intel_cnl_hba_vops = { static struct ufs_hba_variant_ops ufs_intel_ehl_hba_vops = { .name = "intel-pci", + .nonblocking = true, .init = ufs_intel_ehl_init, .exit = ufs_intel_common_exit, .link_startup_notify = ufs_intel_link_startup_notify, @@ -463,6 +465,7 @@ static struct ufs_hba_variant_ops ufs_intel_ehl_hba_vops = { static struct ufs_hba_variant_ops ufs_intel_lkf_hba_vops = { .name = "intel-pci", + .nonblocking = true, .init = ufs_intel_lkf_init, .exit = ufs_intel_common_exit, .hce_enable_notify = ufs_intel_hce_enable_notify, @@ -475,6 +478,7 @@ static struct ufs_hba_variant_ops ufs_intel_lkf_hba_vops = { static struct ufs_hba_variant_ops ufs_intel_adl_hba_vops = { .name = "intel-pci", + .nonblocking = true, .init = ufs_intel_adl_init, .exit = ufs_intel_common_exit, .link_startup_notify = ufs_intel_link_startup_notify, @@ -484,6 +488,7 @@ static struct ufs_hba_variant_ops ufs_intel_adl_hba_vops = { static struct ufs_hba_variant_ops ufs_intel_mtl_hba_vops = { .name = "intel-pci", + .nonblocking = true, .init = ufs_intel_mtl_init, .exit = ufs_intel_common_exit, .hce_enable_notify = ufs_intel_hce_enable_notify, @@ -538,6 +543,7 @@ static void ufshcd_pci_remove(struct pci_dev *pdev) static int ufshcd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) { + const struct ufs_hba_variant_ops *vops; struct ufs_host *ufs_host; struct ufs_hba *hba; void __iomem *mmio_base; @@ -559,14 +565,14 @@ ufshcd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) mmio_base = pcim_iomap_table(pdev)[0]; - err = ufshcd_alloc_host(&pdev->dev, &hba); + vops = (const struct ufs_hba_variant_ops *)id->driver_data; + + err = __ufshcd_alloc_host(&pdev->dev, &hba, vops); if (err) { dev_err(&pdev->dev, "Allocation failed\n"); return err; } - hba->vops = (struct ufs_hba_variant_ops *)id->driver_data; - err = ufshcd_init(hba, mmio_base, pdev->irq); if (err) { dev_err(&pdev->dev, "Initialization failed\n"); diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h index 8039c2b72502..dbf2312ad756 100644 --- a/include/ufs/ufshcd.h +++ b/include/ufs/ufshcd.h @@ -274,6 +274,8 @@ struct ufs_pwr_mode_info { /** * struct ufs_hba_variant_ops - variant specific callbacks * @name: variant name + * @nonblocking: queuecommand will not block (incompatible with + * UFSHCD_CAP_CLK_GATING) * @init: called when the driver is initialized * @exit: called to cleanup everything done in init * @get_ufs_hci_version: called to get UFS HCI version @@ -310,6 +312,7 @@ struct ufs_pwr_mode_info { */ struct ufs_hba_variant_ops { const char *name; + bool nonblocking; int (*init)(struct ufs_hba *); void (*exit)(struct ufs_hba *); u32 (*get_ufs_hci_version)(struct ufs_hba *); @@ -1225,7 +1228,20 @@ static inline void ufshcd_rmwl(struct ufs_hba *hba, u32 mask, u32 val, u32 reg) ufshcd_writel(hba, tmp, reg); } -int ufshcd_alloc_host(struct device *, struct ufs_hba **); +int __ufshcd_alloc_host(struct device *, struct ufs_hba **, + const struct ufs_hba_variant_ops *); + +/** + * ufshcd_alloc_host - allocate Host Bus Adapter (HBA) + * @dev: pointer to device handle + * @hba_handle: driver private handle + * Returns 0 on success, non-zero value on failure + */ +static inline int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) +{ + return __ufshcd_alloc_host(dev, hba_handle, NULL); +} + void ufshcd_dealloc_host(struct ufs_hba *); int ufshcd_hba_enable(struct ufs_hba *hba); int ufshcd_init(struct ufs_hba *, void __iomem *, unsigned int);
On 5/23/23 22:55, Adrian Hunter wrote: > On 23/05/23 22:57, Bart Van Assche wrote: >> On 5/23/23 12:19, Adrian Hunter wrote: >>> On 23/05/23 20:10, Bart Van Assche wrote: >>>> The overhead of BLK_MQ_F_BLOCKING is small relative to the >>>> time required to queue a UFS command so I think enabling >>>> BLK_MQ_F_BLOCKING for all UFS host controllers is fine. >>> >>> Doesn't it also force the queue to be run asynchronously always? >>> >>> But in any case, it doesn't seem like something to force on >>> drivers just because it would take a bit more coding to make it >>> optional. >> >> Making BLK_MQ_F_BLOCKING optional would complicate testing of the >> UFS driver. Although it is possible to make BLK_MQ_F_BLOCKING >> optional, I'm wondering whether it is worth it? I haven't noticed >> any performance difference in my tests with BLK_MQ_F_BLOCKING >> enabled compared to BLK_MQ_F_BLOCKING disabled. > > It is hard to know the effects, especially wrt to future hardware. Are you perhaps referring to performance effects? I think the block layer can be modified to run the queue synchronously in most cases even if BLK_MQ_F_BLOCKING is set. The patch below works fine but is probably not acceptable for upstream because it uses in_atomic(): diff --git a/block/blk-mq.c b/block/blk-mq.c index 551e7760f45e..00fbe0aa56b5 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1471,9 +1471,23 @@ static void blk_mq_requeue_work(struct work_struct *work) blk_mq_run_hw_queues(q, false); } +static bool may_sleep(void) +{ +#ifdef CONFIG_PREEMPT_COUNT + return !in_atomic() && !irqs_disabled(); +#else + return false; +#endif +} + void blk_mq_kick_requeue_list(struct request_queue *q) { + if (may_sleep()) { + blk_mq_requeue_work(&q->requeue_work.work); + return; + } kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0); + } EXPORT_SYMBOL(blk_mq_kick_requeue_list); @@ -2228,7 +2242,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) if (!need_run) return; - if (async || (hctx->flags & BLK_MQ_F_BLOCKING) || + if (async || (hctx->flags & BLK_MQ_F_BLOCKING && !may_sleep()) || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { blk_mq_delay_run_hw_queue(hctx, 0); return; > What about something like this? [ ... ] This introduces a redundancy and a potential for a conflict between the "nonblocking" flag and the UFSHCD_CAP_CLK_GATING flag. It is unfortunate that hba->caps is set so late otherwise we could use the result of (hba->caps & UFSHCD_CAP_CLK_GATING) to check whether or not BLK_MQ_F_BLOCKING is needed. Additionally, this patch introduces a use-after-free issue since it causes scsi_host_alloc() to store a pointer to a stack variable (sht) into a SCSI host structure. Bart.
On 26/05/23 00:16, Bart Van Assche wrote: > On 5/23/23 22:55, Adrian Hunter wrote: >> On 23/05/23 22:57, Bart Van Assche wrote: >>> On 5/23/23 12:19, Adrian Hunter wrote: >>>> On 23/05/23 20:10, Bart Van Assche wrote: >>>>> The overhead of BLK_MQ_F_BLOCKING is small relative to the >>>>> time required to queue a UFS command so I think enabling BLK_MQ_F_BLOCKING for all UFS host controllers is fine. >>>> >>>> Doesn't it also force the queue to be run asynchronously always? >>>> >>>> But in any case, it doesn't seem like something to force on drivers just because it would take a bit more coding to make it optional. >>> >>> Making BLK_MQ_F_BLOCKING optional would complicate testing of the UFS driver. Although it is possible to make BLK_MQ_F_BLOCKING optional, I'm wondering whether it is worth it? I haven't noticed any performance difference in my tests with BLK_MQ_F_BLOCKING enabled compared to BLK_MQ_F_BLOCKING disabled. >> >> It is hard to know the effects, especially wrt to future hardware. > > Are you perhaps referring to performance effects? I think the block > layer can be modified to run the queue synchronously in most cases even > if BLK_MQ_F_BLOCKING is set. The patch below works fine but is probably > not acceptable for upstream because it uses in_atomic(): [ ... ] Why would we want to when we don't have to? >> What about something like this? [ ... ] > > This introduces a redundancy and a potential for a conflict between the > "nonblocking" flag and the UFSHCD_CAP_CLK_GATING flag. It is unfortunate > that hba->caps is set so late otherwise we could use the result of > (hba->caps & UFSHCD_CAP_CLK_GATING) to check whether or not > BLK_MQ_F_BLOCKING is needed. > > Additionally, this patch introduces a use-after-free issue since it > causes scsi_host_alloc() to store a pointer to a stack variable (sht) > into a SCSI host structure. So with those fixed and the vops->may_block instead of vops->nonblocking: diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 82321b8b32bc..6a4389f02b4e 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -2027,6 +2027,11 @@ static void ufshcd_init_clk_gating(struct ufs_hba *hba) if (!ufshcd_is_clkgating_allowed(hba)) return; + if (!hba->host->hostt->queuecommand_may_block) { + dev_warn(hba->dev, "Nonblocking queue, so clock gating is not enabled!\n"); + return; + } + hba->clk_gating.state = CLKS_ON; hba->clk_gating.delay_ms = 150; @@ -8708,33 +8713,41 @@ static struct ufs_hba_variant_params ufs_hba_vps = { .ondemand_data.downdifferential = 5, }; -static const struct scsi_host_template ufshcd_driver_template = { - .module = THIS_MODULE, - .name = UFSHCD, - .proc_name = UFSHCD, - .map_queues = ufshcd_map_queues, - .queuecommand = ufshcd_queuecommand, - .mq_poll = ufshcd_poll, - .slave_alloc = ufshcd_slave_alloc, - .slave_configure = ufshcd_slave_configure, - .slave_destroy = ufshcd_slave_destroy, - .change_queue_depth = ufshcd_change_queue_depth, - .eh_abort_handler = ufshcd_abort, - .eh_device_reset_handler = ufshcd_eh_device_reset_handler, - .eh_host_reset_handler = ufshcd_eh_host_reset_handler, - .eh_timed_out = ufshcd_eh_timed_out, - .this_id = -1, - .sg_tablesize = SG_ALL, - .cmd_per_lun = UFSHCD_CMD_PER_LUN, - .can_queue = UFSHCD_CAN_QUEUE, - .max_segment_size = PRDT_DATA_BYTE_COUNT_MAX, - .max_sectors = (1 << 20) / SECTOR_SIZE, /* 1 MiB */ - .max_host_blocked = 1, - .track_queue_depth = 1, - .skip_settle_delay = 1, +#define UFSHCD_SHT_COMMON \ + .module = THIS_MODULE, \ + .name = UFSHCD, \ + .proc_name = UFSHCD, \ + .map_queues = ufshcd_map_queues, \ + .queuecommand = ufshcd_queuecommand, \ + .mq_poll = ufshcd_poll, \ + .slave_alloc = ufshcd_slave_alloc, \ + .slave_configure = ufshcd_slave_configure, \ + .slave_destroy = ufshcd_slave_destroy, \ + .change_queue_depth = ufshcd_change_queue_depth, \ + .eh_abort_handler = ufshcd_abort, \ + .eh_device_reset_handler = ufshcd_eh_device_reset_handler, \ + .eh_host_reset_handler = ufshcd_eh_host_reset_handler, \ + .eh_timed_out = ufshcd_eh_timed_out, \ + .this_id = -1, \ + .sg_tablesize = SG_ALL, \ + .cmd_per_lun = UFSHCD_CMD_PER_LUN, \ + .can_queue = UFSHCD_CAN_QUEUE, \ + .max_segment_size = PRDT_DATA_BYTE_COUNT_MAX, \ + .max_sectors = (1 << 20) / SECTOR_SIZE, /* 1 MiB */ \ + .max_host_blocked = 1, \ + .track_queue_depth = 1, \ + .skip_settle_delay = 1, \ + .sdev_groups = ufshcd_driver_groups, \ + .rpm_autosuspend_delay = RPM_AUTOSUSPEND_DELAY_MS + +static const struct scsi_host_template ufshcd_sht_blocking = { + UFSHCD_SHT_COMMON, .queuecommand_may_block = true, - .sdev_groups = ufshcd_driver_groups, - .rpm_autosuspend_delay = RPM_AUTOSUSPEND_DELAY_MS, +}; + +static const struct scsi_host_template ufshcd_sht_nonblocking = { + UFSHCD_SHT_COMMON, + .queuecommand_may_block = false, }; static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg, @@ -10049,13 +10062,16 @@ static int ufshcd_set_dma_mask(struct ufs_hba *hba) } /** - * ufshcd_alloc_host - allocate Host Bus Adapter (HBA) + * __ufshcd_alloc_host - allocate Host Bus Adapter (HBA) * @dev: pointer to device handle * @hba_handle: driver private handle + * @vops: pointer to variant specific operations * Returns 0 on success, non-zero value on failure */ -int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) +int __ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle, + const struct ufs_hba_variant_ops *vops) { + const struct scsi_host_template *sht; struct Scsi_Host *host; struct ufs_hba *hba; int err = 0; @@ -10067,8 +10083,12 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) goto out_error; } - host = scsi_host_alloc(&ufshcd_driver_template, - sizeof(struct ufs_hba)); + if (vops && vops->may_block) + sht = &ufshcd_sht_blocking; + else + sht = &ufshcd_sht_nonblocking; + + host = scsi_host_alloc(sht, sizeof(struct ufs_hba)); if (!host) { dev_err(dev, "scsi_host_alloc failed\n"); err = -ENOMEM; @@ -10078,6 +10098,7 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) hba = shost_priv(host); hba->host = host; hba->dev = dev; + hba->vops = vops; hba->dev_ref_clk_freq = REF_CLK_FREQ_INVAL; hba->nop_out_timeout = NOP_OUT_TIMEOUT; ufshcd_set_sg_entry_size(hba, sizeof(struct ufshcd_sg_entry)); @@ -10089,7 +10110,7 @@ int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) out_error: return err; } -EXPORT_SYMBOL(ufshcd_alloc_host); +EXPORT_SYMBOL(__ufshcd_alloc_host); /* This function exists because blk_mq_alloc_tag_set() requires this. */ static blk_status_t ufshcd_queue_tmf(struct blk_mq_hw_ctx *hctx, diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h index 8039c2b72502..dbeb879b47d1 100644 --- a/include/ufs/ufshcd.h +++ b/include/ufs/ufshcd.h @@ -274,6 +274,7 @@ struct ufs_pwr_mode_info { /** * struct ufs_hba_variant_ops - variant specific callbacks * @name: variant name + * @may_block: queuecommand may block (required with UFSHCD_CAP_CLK_GATING) * @init: called when the driver is initialized * @exit: called to cleanup everything done in init * @get_ufs_hci_version: called to get UFS HCI version @@ -310,6 +311,7 @@ struct ufs_pwr_mode_info { */ struct ufs_hba_variant_ops { const char *name; + bool may_block; int (*init)(struct ufs_hba *); void (*exit)(struct ufs_hba *); u32 (*get_ufs_hci_version)(struct ufs_hba *); @@ -1225,7 +1227,20 @@ static inline void ufshcd_rmwl(struct ufs_hba *hba, u32 mask, u32 val, u32 reg) ufshcd_writel(hba, tmp, reg); } -int ufshcd_alloc_host(struct device *, struct ufs_hba **); +int __ufshcd_alloc_host(struct device *, struct ufs_hba **, + const struct ufs_hba_variant_ops *); + +/** + * ufshcd_alloc_host - allocate Host Bus Adapter (HBA) + * @dev: pointer to device handle + * @hba_handle: driver private handle + * Returns 0 on success, non-zero value on failure + */ +static inline int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle) +{ + return __ufshcd_alloc_host(dev, hba_handle, NULL); +} + void ufshcd_dealloc_host(struct ufs_hba *); int ufshcd_hba_enable(struct ufs_hba *hba); int ufshcd_init(struct ufs_hba *, void __iomem *, unsigned int);
On 5/26/23 00:11, Adrian Hunter wrote: > Why would we want to when we don't have to? Anyone is allowed to formulate objections to a patch but when objecting to a patch or an approach please explain *why*. I think I already explained that unconditionally enabling BLK_MQ_F_BLOCKING makes testing the UFS host controller driver easier. > So with those fixed and the vops->may_block instead of vops->nonblocking: [ ... ] I think a much simpler solution exists. I plan to post a new version of this patch series soon. Bart.
On 26/05/23 20:27, Bart Van Assche wrote: > On 5/26/23 00:11, Adrian Hunter wrote: >> Why would we want to when we don't have to? > > Anyone is allowed to formulate objections to a patch but when objecting to a patch or an approach please explain *why*. I think I already explained that unconditionally enabling BLK_MQ_F_BLOCKING makes testing the UFS host controller driver easier. I don't think you are claiming blocking queues are better for block drivers than non-blocking queues, so it is quite reasonable to stay with non-blocking queues. I am not sure testing is really relevant to this discussion, but it seems like different combinations need to be tested anyway e.g. testing with / without clock gating is the same testing with / without blocking. > >> So with those fixed and the vops->may_block instead of vops->nonblocking: > > [ ... ] > > I think a much simpler solution exists. I plan to post a new version of this patch series soon. Thank you!
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 7ee150d67d49..993034ac1696 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -8756,6 +8756,7 @@ static const struct scsi_host_template ufshcd_driver_template = { .max_host_blocked = 1, .track_queue_depth = 1, .skip_settle_delay = 1, + .queuecommand_may_block = true, .sdev_groups = ufshcd_driver_groups, .rpm_autosuspend_delay = RPM_AUTOSUSPEND_DELAY_MS, };
Prepare for adding code in ufshcd_queuecommand() that may sleep. Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- drivers/ufs/core/ufshcd.c | 1 + 1 file changed, 1 insertion(+)