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Re: [Linaro-mm-sig] [RFC] Cross-driver ww transaction lock lists

by Daniel Vetter

On Thu, Apr 15, 2021 at 05:40:24PM +0200, Thomas Hellström (Intel) wrote: > > On 4/15/21 4:40 PM, Daniel Vetter wrote: > > On Thu, Apr 15, 2021 at 4:02 PM Thomas Hellström (Intel) > > <thomas_os(a)shipmail.org> wrote: > > > > > > On 4/15/21 3:37 PM, Daniel Vetter wrote: > > > > On Tue, Apr 13, 2021 at 09:57:06AM +0200, Christian König wrote: > > > > > Am 13.04.21 um 09:50 schrieb Thomas Hellström: > > > > > > Hi! > > > > > > > > > > > > During the dma_resv conversion of the i915 driver, we've been using ww > > > > > > transaction lock lists to keep track of ww_mutexes that are locked > > > > > > during the transaction so that they can be batch unlocked at suitable > > > > > > locations. Including also the LMEM/VRAM eviction we've ended up with > > > > > > two static lists per transaction context; one typically unlocked at the > > > > > > end of transaction and one initialized before and unlocked after each > > > > > > buffer object validate. This enables us to do sleeping locking at > > > > > > eviction and keep objects locked on the eviction list until we > > > > > > eventually succeed allocating memory (modulo minor flaws of course). > > > > > > > > > > > > It would be beneficial with the i915 TTM conversion to be able to > > > > > > introduce a similar functionality that would work in ttm but also > > > > > > cross-driver in, for example move_notify. It would also be beneficial > > > > > > to be able to put any dma_resv ww mutex on the lists, and not require > > > > > > it to be embedded in a particular object type. > > > > > > > > > > > > I started scetching on some utilities for this. For TTM, for example, > > > > > > the idea would be to pass a list head for the ww transaction lock list > > > > > > in the ttm_operation_ctx. A function taking a ww_mutex could then > > > > > > either attach a grabbed lock to the list for batch unlocking, or be > > > > > > responsible for unlocking when the lock's scope is exited. It's also > > > > > > possible to create sublists if so desired. I believe the below would be > > > > > > sufficient to cover the i915 functionality. > > > > > > > > > > > > Any comments and suggestions appreciated! > > > > > ah yes Daniel and I haven been discussing something like this for years. > > > > > > > > > > I also came up with rough implementation, but we always ran into lifetime > > > > > issues. > > > > > > > > > > In other words the ww_mutexes which are on the list would need to be kept > > > > > alive until unlocked. > > > > > > > > > > Because of this we kind of backed up and said we would need this on the GEM > > > > > level instead of working with dma_resv objects. > > > > Yeah there's a few funny concerns here that make this awkward: > > > > - For simplicity doing these helpers at the gem level should make things a > > > > bit easier, because then we have a standard way to drop the reference. > > > > It does mean that the only thing you can lock like this are gem objects, > > > > but I think that's fine. At least for a first cut. > > > > > > > > - This is a bit awkward for vmwgfx, but a) Zack has mentioned he's looking > > > > into adopting gem bo internally to be able to drop a pile of code and > > > > stop making vmwgfx the only special-case we have b) drivers which don't > > > > need this won't need this, so should be fine. > > > > > > > > The other awkward thing I guess is that ttm would need to use the > > > > embedded kref from the gem bo, but that should be transparent I think. > > > > > > > > - Next up is dma-buf: For i915 we'd like to do the same eviction trick > > > > also through p2p dma-buf callbacks, so that this works the same as > > > > eviction/reservation within a gpu. But for these internal bo you might > > > > not have a dma-buf, so we can't just lift the trick to the dma-buf > > > > level. But I think if we pass e.g. a struct list_head and a callback to > > > > unreference/unlock all the buffers in there to the exporter, plus > > > > similar for the slowpath lock, then that should be doable without > > > > glorious layering inversions between dma-buf and gem. > > > > > > > > I think for dma-buf it should even be ok if this requires that we > > > > allocate an entire structure with kmalloc or something, allocating > > > > memory while holding dma_resv is ok. > > > Yes, the thing here with the suggested helpers is that you would just > > > embed a trans_lockitem struct in the gem object (and defines the gem > > > object ops). Otherwise and for passing to dma-buf this is pretty much > > > exactly what you are suggesting, but the huge benefit of encapsulating > > > the needed members like this is that when we need to change something we > > > change it in just one place. > > > > > > For anything that doesn't have a gem object (dma-buf, vmwgfx or > > > whatever) you have the choice of either allocating a struct > > > trans_lockitem or embed it wherever you prefer. In particular, this is > > > beneficial where you have a single dma-resv class ww-mutex sitting > > > somewhere in the way and you don't want to needlessly have a gem object > > > that embeds it. > > The thing is, everyone who actually uses dma_resv_lock has a > > gem_buffer_object underneath. So it feels a bit like flexibility for > > no real need, and I think it would make it slightly more awkard for > > gem drivers to neatly integrate into their cs path. The lockitem > > struct works, but it is a bit cumbersome. > > Well that's partly because of it's impossible to use a standalone ww_mutex > in a locking transaction that can only add gem objects to the list :/. > Already in the i915 driver we have and may want to add various places where > we have dead gem objects sitting because of this. > > Also, more importantly, If we pass a list down the dma-buf move_notify(), a > trans_lockitem is pretty much exactly what we expect back (except of course > for the private pointer). It would be odd if we'd expect all list items to > be gem objects when it's a dma-buf interface? > > > > > Also if we add some wrappers to e.g. add a gem_bo to the ctx, then if > > we decide to slip the lockitem in there, we still only need to touch > > the helper code, and not all drivers. > > Well, yes assuming we always have an embedding gem object for a dma_resv > that might be true, but either way I don't really expect the gem helpers to > look very different. We will need the ops anyway and a specialized context > so if the only thing we're debating is whether or not to embed a struct in > the gem object, unless you really insist on using the gem object initially, > I suggest we try this and if it becomes awkward, just > s/trans_lockitem/drm_gem_object/ Hm yeah I think you convinced me this is a bit a bikeshed :-) Maybe call it dma_resv_lockitem or so if we go with top-level generic solution. And then embed it wheterever we feel like. The annoying thing with tha generic thing is that I'd like to avoid the full callback pointer in all the gem objects, but maybe another ptr really doesn't matter on this if we add a linked list anyway ... -Daniel > > /Thomas > > > > -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch

5 years, 1 month

Re: [Linaro-mm-sig] [RFC] Cross-driver ww transaction lock lists

by Daniel Vetter

On Thu, Apr 15, 2021 at 4:02 PM Thomas Hellström (Intel) <thomas_os(a)shipmail.org> wrote: > > > On 4/15/21 3:37 PM, Daniel Vetter wrote: > > On Tue, Apr 13, 2021 at 09:57:06AM +0200, Christian König wrote: > >> > >> Am 13.04.21 um 09:50 schrieb Thomas Hellström: > >>> Hi! > >>> > >>> During the dma_resv conversion of the i915 driver, we've been using ww > >>> transaction lock lists to keep track of ww_mutexes that are locked > >>> during the transaction so that they can be batch unlocked at suitable > >>> locations. Including also the LMEM/VRAM eviction we've ended up with > >>> two static lists per transaction context; one typically unlocked at the > >>> end of transaction and one initialized before and unlocked after each > >>> buffer object validate. This enables us to do sleeping locking at > >>> eviction and keep objects locked on the eviction list until we > >>> eventually succeed allocating memory (modulo minor flaws of course). > >>> > >>> It would be beneficial with the i915 TTM conversion to be able to > >>> introduce a similar functionality that would work in ttm but also > >>> cross-driver in, for example move_notify. It would also be beneficial > >>> to be able to put any dma_resv ww mutex on the lists, and not require > >>> it to be embedded in a particular object type. > >>> > >>> I started scetching on some utilities for this. For TTM, for example, > >>> the idea would be to pass a list head for the ww transaction lock list > >>> in the ttm_operation_ctx. A function taking a ww_mutex could then > >>> either attach a grabbed lock to the list for batch unlocking, or be > >>> responsible for unlocking when the lock's scope is exited. It's also > >>> possible to create sublists if so desired. I believe the below would be > >>> sufficient to cover the i915 functionality. > >>> > >>> Any comments and suggestions appreciated! > >> ah yes Daniel and I haven been discussing something like this for years. > >> > >> I also came up with rough implementation, but we always ran into lifetime > >> issues. > >> > >> In other words the ww_mutexes which are on the list would need to be kept > >> alive until unlocked. > >> > >> Because of this we kind of backed up and said we would need this on the GEM > >> level instead of working with dma_resv objects. > > Yeah there's a few funny concerns here that make this awkward: > > - For simplicity doing these helpers at the gem level should make things a > > bit easier, because then we have a standard way to drop the reference. > > It does mean that the only thing you can lock like this are gem objects, > > but I think that's fine. At least for a first cut. > > > > - This is a bit awkward for vmwgfx, but a) Zack has mentioned he's looking > > into adopting gem bo internally to be able to drop a pile of code and > > stop making vmwgfx the only special-case we have b) drivers which don't > > need this won't need this, so should be fine. > > > > The other awkward thing I guess is that ttm would need to use the > > embedded kref from the gem bo, but that should be transparent I think. > > > > - Next up is dma-buf: For i915 we'd like to do the same eviction trick > > also through p2p dma-buf callbacks, so that this works the same as > > eviction/reservation within a gpu. But for these internal bo you might > > not have a dma-buf, so we can't just lift the trick to the dma-buf > > level. But I think if we pass e.g. a struct list_head and a callback to > > unreference/unlock all the buffers in there to the exporter, plus > > similar for the slowpath lock, then that should be doable without > > glorious layering inversions between dma-buf and gem. > > > > I think for dma-buf it should even be ok if this requires that we > > allocate an entire structure with kmalloc or something, allocating > > memory while holding dma_resv is ok. > > Yes, the thing here with the suggested helpers is that you would just > embed a trans_lockitem struct in the gem object (and defines the gem > object ops). Otherwise and for passing to dma-buf this is pretty much > exactly what you are suggesting, but the huge benefit of encapsulating > the needed members like this is that when we need to change something we > change it in just one place. > > For anything that doesn't have a gem object (dma-buf, vmwgfx or > whatever) you have the choice of either allocating a struct > trans_lockitem or embed it wherever you prefer. In particular, this is > beneficial where you have a single dma-resv class ww-mutex sitting > somewhere in the way and you don't want to needlessly have a gem object > that embeds it. The thing is, everyone who actually uses dma_resv_lock has a gem_buffer_object underneath. So it feels a bit like flexibility for no real need, and I think it would make it slightly more awkard for gem drivers to neatly integrate into their cs path. The lockitem struct works, but it is a bit cumbersome. Also if we add some wrappers to e.g. add a gem_bo to the ctx, then if we decide to slip the lockitem in there, we still only need to touch the helper code, and not all drivers. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch

5 years, 1 month

Re: [Linaro-mm-sig] [RFC] Cross-driver ww transaction lock lists

by Christian König

Am 13.04.21 um 09:50 schrieb Thomas Hellström: > Hi! > > During the dma_resv conversion of the i915 driver, we've been using ww > transaction lock lists to keep track of ww_mutexes that are locked > during the transaction so that they can be batch unlocked at suitable > locations. Including also the LMEM/VRAM eviction we've ended up with > two static lists per transaction context; one typically unlocked at the > end of transaction and one initialized before and unlocked after each > buffer object validate. This enables us to do sleeping locking at > eviction and keep objects locked on the eviction list until we > eventually succeed allocating memory (modulo minor flaws of course). > > It would be beneficial with the i915 TTM conversion to be able to > introduce a similar functionality that would work in ttm but also > cross-driver in, for example move_notify. It would also be beneficial > to be able to put any dma_resv ww mutex on the lists, and not require > it to be embedded in a particular object type. > > I started scetching on some utilities for this. For TTM, for example, > the idea would be to pass a list head for the ww transaction lock list > in the ttm_operation_ctx. A function taking a ww_mutex could then > either attach a grabbed lock to the list for batch unlocking, or be > responsible for unlocking when the lock's scope is exited. It's also > possible to create sublists if so desired. I believe the below would be > sufficient to cover the i915 functionality. > > Any comments and suggestions appreciated! ah yes Daniel and I haven been discussing something like this for years. I also came up with rough implementation, but we always ran into lifetime issues. In other words the ww_mutexes which are on the list would need to be kept alive until unlocked. Because of this we kind of backed up and said we would need this on the GEM level instead of working with dma_resv objects. Regards, Christian. > > 8<------------------------------------------------------ > > #ifndef _TRANSACTION_LOCKLIST_H_ > #define _TRANSACTION_LOCKLIST_H_ > > struct trans_lockitem; > > /** > * struct trans_locklist_ops - Ops structure for the ww locklist > functionality. > * > * Typically a const struct trans_locklist_ops is defined for each type > that > * embeds a struct trans_lockitem, or hav a struct trans_lockitem > pointing > * at it using the private pointer. It can be a buffer object, > reservation > * object, a single ww_mutex or even a sublist of trans_lockitems. > */ > struct trans_locklist_ops { > /** > * slow_lock: Slow lock to relax the transaction. Only used by > * a contending lock item. > * @item: The struct trans_lockitem to lock > * @intr: Whether to lock interruptible > * > * Return: -ERESTARTSYS: Hit a signal when relaxing, > * -EAGAIN, relaxing succesful, but the contending lock > * remains unlocked. > */ > int (*slow_lock) (struct trans_lockitem *item, bool intr); > > /** > * unlock: Unlock. > * @item: The struct trans_lockitem to unlock. > */ > void (*unlock) (struct trans_lockitem *item); > > /** > * unlock: Unlock. > * @item: The struct trans_lockitem to put. This function may > be NULL. > */ > void (*put) (struct trans_lockitem *item); > }; > > /** > * struct trans_lockitem > * @ops: Pointer to an Ops structure for this lockitem. > * @link: List link for the transaction locklist. > * @private: Private info. > * @relax_unlock: Unlock contending lock after relaxation since it is > * likely not needed after a transaction restart. > * > * A struct trans_lockitem typically represents a single lock, but is > * generic enough to represent a sublist of locks. It can either be > * embedded, or allocated on demand. A kmem_cache might be beneficial. > */ > struct trans_lockitem { > const struct trans_locklist_ops *ops; > struct list_head link; > u32 relax_unlock:1; > void *private; > }; > > /* unlock example */ > static inline void trans_unlock_put_all(struct list_head *list) > { > struct trans_lockitem *lock, *next; > > list_for_each_entry_safe(lock, next, typeof(*lock), link) { > lock->ops->unlock(lock); > list_del_init(&lock->link); > if (lock->ops_put) > lock->ops->put(lock); > } > } > > /* Backoff example */ > static inline int __must_check trans_backoff(struct list_head *list, > bool intr, > struct trans_lockitem > *contending) > { > int ret = 0; > > trans_unlock_put_all(list); > if (contending) { > ret = contending->ops->slow_lock(contending, intr); > if (!ret && contending->relax_unlock) > contending->unlock(contending); > if (ret == -EAGAIN) > ret = 0; > contending->ops->put(contending); > } > > return ret; > } > > > #endif _TRANSACTION_LOCKLIST_ > >

5 years, 1 month

Re: [Linaro-mm-sig] [PATCH] ASoC: fsl: imx-pcm-dma: Don't request dma channel in probe

by Lucas Stach

Hi Robin, Am Mittwoch, dem 14.04.2021 um 14:33 +0000 schrieb Robin Gong: > On 2020/05/20 17:43 Lucas Stach <l.stach(a)pengutronix.de> wrote: > > Am Mittwoch, den 20.05.2020, 16:20 +0800 schrieb Shengjiu Wang: > > > Hi > > > > > > On Tue, May 19, 2020 at 6:04 PM Lucas Stach <l.stach(a)pengutronix.de> > > wrote: > > > > Am Dienstag, den 19.05.2020, 17:41 +0800 schrieb Shengjiu Wang: > > > > > There are two requirements that we need to move the request of dma > > > > > channel from probe to open. > > > > > > > > How do you handle -EPROBE_DEFER return code from the channel request > > > > if you don't do it in probe? > > > > > > I use the dma_request_slave_channel or dma_request_channel instead of > > > dmaengine_pcm_request_chan_of. so there should be not -EPROBE_DEFER > > > return code. > > > > This is a pretty weak argument. The dmaengine device might probe after you > > try to get the channel. Using a function to request the channel that doesn't > > allow you to handle probe deferral is IMHO a bug and should be fixed, instead > > of building even more assumptions on top of it. > > > > > > > - When dma device binds with power-domains, the power will be > > > > > enabled when we request dma channel. If the request of dma channel > > > > > happen on probe, then the power-domains will be always enabled > > > > > after kernel boot up, which is not good for power saving, so we > > > > > need to move the request of dma channel to .open(); > > > > > > > > This is certainly something which could be fixed in the dmaengine > > > > driver. > > > > > > Dma driver always call the pm_runtime_get_sync in > > > device_alloc_chan_resources, the device_alloc_chan_resources is called > > > when channel is requested. so power is enabled on channel request. > > > > So why can't you fix the dmaengine driver to do that RPM call at a later time > > when the channel is actually going to be used? This will allow further power > > savings with other slave devices than the audio PCM. > Hi Lucas, > Thanks for your suggestion. I have tried to implement runtime autosuspend in > fsl-edma driver on i.mx8qm/qxp with delay time (2 sec) for this feature as below > (or you can refer to drivers/dma/qcom/hidma.c), and pm_runtime_get_sync/ > pm_runtime_put_autosuspend in all dmaengine driver interface like > device_alloc_chan_resources/device_prep_slave_sg/device_prep_dma_cyclic/ > device_tx_status... > > > pm_runtime_use_autosuspend(fsl_chan->dev); > pm_runtime_set_autosuspend_delay(fsl_chan->dev, 2000); > > That could resolve this audio case since the autosuspend could suspend runtime after > 2 seconds if there is no further dma transfer but only channel request(device_alloc_chan_resources). > But unfortunately, it cause another issue. As you know, on our i.mx8qm/qxp, > power domain done by scfw (drivers/firmware/imx/scu-pd.c) over mailbox: > imx_sc_pd_power()->imx_scu_call_rpc()-> imx_scu_ipc_write()->mbox_send_message() > which means have to 'waits for completion', meanwhile, some driver like tty will call dmaengine > interfaces in non-atomic case as below, > > static int uart_write(struct tty_struct *tty, const unsigned char *buf, int count) > { > ....... > port = uart_port_lock(state, flags); > ...... > __uart_start(tty); //call start_tx()->dmaengine_prep_slave_sg... > uart_port_unlock(port, flags); > return ret; > } > > Thus dma runtime resume may happen in that timing window and cause kernel alarm. > I'm not sure whether there are similar limitations on other driver subsystem. But for me, > It looks like the only way to resolve the contradiction between tty and scu-pd (hardware > limitation on i.mx8qm/qxp) is to give up autosuspend and keep pm_runtime_get_sync > only in device_alloc_chan_resources because request channel is a safe non-atomic phase. > Do you have any idea? Thanks in advance. If you look closely at the driver you used as an example (hidma.c) it looks like there is already something in there, which looks very much like what you need here: In hidma_issue_pending() the driver tries to get the device to runtime resume. If this doesn't work, maybe due to the power domain code not being able to be called in atomic context, the actual work of waking up the dma hardware and issuing the descriptor is shunted to a tasklet. If I'm reading this right, this is exactly what you need here to be able to call the dmaengine code from atomic context: try the rpm get and issue immediately when possible, otherwise shunt the work to a non- atomic context where you can deal with the requirements of scu-pd. Also you don't need the runtime resume in all of the functions you mentioned. From a quick look into the edma driver it looks like for example the prep_slave_dma() function only touches data structures in memory, so you don't actually need the device to be awake at that point. Only later in the flow when you write registers in the dma hardware and actually issue the transfer you need to wake the device from sleep. Regards, Lucas > > > > > > > > > > > > - With FE-BE case, if the dma channel is requested in probe, then > > > > > there will be below issue, which is caused by that the dma channel > > > > > will be requested duplicately > > > > > > > > Why is this requested a second time? Is this just some missing > > > > cleanup on a deferred probe path? > > > > > > Not relate with deferred probe. With DMA1->ASRC->DMA2->ESAI case, the > > > DMA1->ASRC->DMA2 is in FE, ESAI is in BE. When ESAI drvier probe, > > > DMA3 channel is created with ESAI's "dma:tx" (DMA3 channel > > > is not used in this FE-BE case). When FE-BE startup, DMA2 > > > channel is created, it needs the ESAI's "dma:tx", so below warning > > > comes out. > > > > > > > Regards, > > > > Lucas > > > > > > > > > [ 638.906268] sysfs: cannot create duplicate filename > > '/devices/soc0/soc/2000000.bus/2000000.spba-bus/2024000.esai/dma:tx' > > > > > [ 638.919061] CPU: 1 PID: 673 Comm: aplay Not tainted > > > > > 5.7.0-rc1-12956-gfc64b2585593 #287 [ 638.927113] Hardware name: > > > > > Freescale i.MX6 Quad/DualLite (Device Tree) [ 638.933690] > > > > > [<c0110dd8>] (unwind_backtrace) from [<c010b8ec>] > > > > > (show_stack+0x10/0x14) [ 638.941464] [<c010b8ec>] (show_stack) > > > > > from [<c0557fc0>] (dump_stack+0xe4/0x118) [ 638.948808] > > > > > [<c0557fc0>] (dump_stack) from [<c032aeb4>] > > > > > (sysfs_warn_dup+0x50/0x64) [ 638.956406] [<c032aeb4>] > > > > > (sysfs_warn_dup) from [<c032b1a8>] > > > > > (sysfs_do_create_link_sd+0xc8/0xd4) > > > > > [ 638.965134] [<c032b1a8>] (sysfs_do_create_link_sd) from > > > > > [<c05dc668>] (dma_request_chan+0xb0/0x210) [ 638.974120] > > > > > [<c05dc668>] (dma_request_chan) from [<c05dc7d0>] > > > > > (dma_request_slave_channel+0x8/0x14) > > > > > [ 638.983111] [<c05dc7d0>] (dma_request_slave_channel) from > > > > > [<c09d5548>] (fsl_asrc_dma_hw_params+0x1e0/0x438) > > > > > [ 638.992881] [<c09d5548>] (fsl_asrc_dma_hw_params) from > > > > > [<c09c1654>] (soc_pcm_hw_params+0x4a0/0x6a8) [ 639.001952] > > > > > [<c09c1654>] (soc_pcm_hw_params) from [<c09c39d4>] > > > > > (dpcm_fe_dai_hw_params+0x70/0xe4) [ 639.010765] [<c09c39d4>] > > > > > (dpcm_fe_dai_hw_params) from [<c099b274>] > > > > > (snd_pcm_hw_params+0x158/0x418) [ 639.019750] [<c099b274>] > > > > > (snd_pcm_hw_params) from [<c099c5a0>] > > (snd_pcm_ioctl+0x734/0x183c) [ 639.028129] [<c099c5a0>] (snd_pcm_ioctl) > > from [<c029ff94>] (ksys_ioctl+0x2ac/0xb98) [ 639.035812] [<c029ff94>] > > (ksys_ioctl) from [<c0100080>] (ret_fast_syscall+0x0/0x28) [ 639.043490] > > Exception stack(0xec529fa8 to 0xec529ff0) > > > > > [ 639.048565] 9fa0: bee84650 01321870 > > 00000004 c25c4111 bee84650 0002000f > > > > > [ 639.056766] 9fc0: bee84650 01321870 01321820 00000036 > > 00001f40 > > > > > 00000000 0002c2f8 00000003 [ 639.064964] 9fe0: b6f483fc bee8451c > > > > > b6ee2655 b6e1dcf8 [ 639.070339] fsl-esai-dai 2024000.esai: Cannot > > > > > create DMA dma:tx symlink > > > > > > > > > > Signed-off-by: Shengjiu Wang <shengjiu.wang(a)nxp.com> > > > > > --- > > > > > sound/soc/fsl/imx-pcm-dma.c | 173 > > > > > +++++++++++++++++++++++++++++++++--- > > > > > 1 file changed, 159 insertions(+), 14 deletions(-) > > > > > > > > > > diff --git a/sound/soc/fsl/imx-pcm-dma.c > > > > > b/sound/soc/fsl/imx-pcm-dma.c index 04a9bc749016..dae53b384df4 > > > > > 100644 > > > > > --- a/sound/soc/fsl/imx-pcm-dma.c > > > > > +++ b/sound/soc/fsl/imx-pcm-dma.c > > > > > @@ -11,6 +11,7 @@ > > > > > #include <linux/dmaengine.h> > > > > > #include <linux/types.h> > > > > > #include <linux/module.h> > > > > > +#include <linux/dma-mapping.h> > > > > > > > > > > #include <sound/core.h> > > > > > #include <sound/pcm.h> > > > > > @@ -29,24 +30,168 @@ static bool filter(struct dma_chan *chan, void > > *param) > > > > > return true; > > > > > } > > > > > > > > > > -static const struct snd_dmaengine_pcm_config > > imx_dmaengine_pcm_config = { > > > > > - .prepare_slave_config = > > snd_dmaengine_pcm_prepare_slave_config, > > > > > - .compat_filter_fn = filter, > > > > > -}; > > > > > +static int imx_pcm_hw_params(struct snd_soc_component > > *component, > > > > > + struct snd_pcm_substream *substream, > > > > > + struct snd_pcm_hw_params *params) { > > > > > + struct snd_pcm_runtime *runtime = substream->runtime; > > > > > + struct snd_soc_pcm_runtime *rtd = substream->private_data; > > > > > + struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0); > > > > > + struct snd_dmaengine_dai_dma_data *dma_data; > > > > > + struct dma_slave_config config; > > > > > + struct dma_chan *chan; > > > > > + int ret = 0; > > > > > > > > > > -int imx_pcm_dma_init(struct platform_device *pdev, size_t size) > > > > > + snd_pcm_set_runtime_buffer(substream, > > &substream->dma_buffer); > > > > > + runtime->dma_bytes = params_buffer_bytes(params); > > > > > + > > > > > + chan = snd_dmaengine_pcm_get_chan(substream); > > > > > + if (!chan) > > > > > + return -EINVAL; > > > > > + > > > > > + ret = snd_hwparams_to_dma_slave_config(substream, params, > > &config); > > > > > + if (ret) > > > > > + return ret; > > > > > + > > > > > + dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream); > > > > > + if (!dma_data) > > > > > + return -EINVAL; > > > > > + > > > > > + snd_dmaengine_pcm_set_config_from_dai_data(substream, > > > > > + dma_data, > > > > > + &config); > > > > > + return dmaengine_slave_config(chan, &config); } > > > > > + > > > > > +static int imx_pcm_hw_free(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream) > > > > > { > > > > > - struct snd_dmaengine_pcm_config *config; > > > > > + snd_pcm_set_runtime_buffer(substream, NULL); > > > > > + return 0; > > > > > +} > > > > > + > > > > > +static snd_pcm_uframes_t imx_pcm_pointer(struct snd_soc_component > > *component, > > > > > + struct snd_pcm_substream > > > > > +*substream) { > > > > > + return snd_dmaengine_pcm_pointer(substream); > > > > > +} > > > > > + > > > > > +static int imx_pcm_trigger(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream, int > > > > > +cmd) { > > > > > + return snd_dmaengine_pcm_trigger(substream, cmd); } > > > > > + > > > > > +static int imx_pcm_open(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream) { > > > > > + struct snd_soc_pcm_runtime *rtd = substream->private_data; > > > > > + bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK; > > > > > + struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0); > > > > > + struct snd_dmaengine_dai_dma_data *dma_data; > > > > > + struct device *dev = component->dev; > > > > > + struct snd_pcm_hardware hw; > > > > > + struct dma_chan *chan; > > > > > + int ret; > > > > > + > > > > > + ret = snd_pcm_hw_constraint_integer(substream->runtime, > > > > > + > > SNDRV_PCM_HW_PARAM_PERIODS); > > > > > + if (ret < 0) { > > > > > + dev_err(dev, "failed to set pcm hw params periods\n"); > > > > > + return ret; > > > > > + } > > > > > + > > > > > + dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream); > > > > > + if (!dma_data) > > > > > + return -EINVAL; > > > > > + > > > > > + chan = dma_request_slave_channel(cpu_dai->dev, tx ? "tx" : "rx"); > > > > > + if (!chan) { > > > > > + /* Try to request channel using compat_filter_fn */ > > > > > + chan = snd_dmaengine_pcm_request_channel(filter, > > > > > + > > dma_data->filter_data); > > > > > + if (!chan) > > > > > + return -ENXIO; > > > > > + } > > > > > > > > > > - config = devm_kzalloc(&pdev->dev, > > > > > - sizeof(struct snd_dmaengine_pcm_config), > > GFP_KERNEL); > > > > > - if (!config) > > > > > - return -ENOMEM; > > > > > - *config = imx_dmaengine_pcm_config; > > > > > + ret = snd_dmaengine_pcm_open(substream, chan); > > > > > + if (ret) > > > > > + goto pcm_open_fail; > > > > > > > > > > - return devm_snd_dmaengine_pcm_register(&pdev->dev, > > > > > - config, > > > > > - SND_DMAENGINE_PCM_FLAG_COMPAT); > > > > > + memset(&hw, 0, sizeof(hw)); > > > > > + hw.info = SNDRV_PCM_INFO_MMAP | > > SNDRV_PCM_INFO_MMAP_VALID | > > > > > + SNDRV_PCM_INFO_INTERLEAVED; > > > > > + hw.periods_min = 2; > > > > > + hw.periods_max = UINT_MAX; > > > > > + hw.period_bytes_min = 256; > > > > > + hw.period_bytes_max = > > dma_get_max_seg_size(chan->device->dev); > > > > > + hw.buffer_bytes_max = IMX_DEFAULT_DMABUF_SIZE; > > > > > + hw.fifo_size = dma_data->fifo_size; > > > > > + > > > > > + /* Refine the hw according to caps of DMA. */ > > > > > + ret = snd_dmaengine_pcm_refine_runtime_hwparams(substream, > > > > > + > > dma_data, > > > > > + &hw, > > > > > + chan); > > > > > + if (ret < 0) > > > > > + goto refine_runtime_hwparams_fail; > > > > > + > > > > > + snd_soc_set_runtime_hwparams(substream, &hw); > > > > > + > > > > > + /* Support allocate memory from IRAM */ > > > > > + ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_IRAM, > > > > > + chan->device->dev, > > > > > + hw.buffer_bytes_max, > > > > > + &substream->dma_buffer); > > > > > + if (ret < 0) > > > > > + goto alloc_pagas_fail; > > > > > + > > > > > + return 0; > > > > > + > > > > > +alloc_pagas_fail: > > > > > +refine_runtime_hwparams_fail: > > > > > + snd_dmaengine_pcm_close(substream); > > > > > +pcm_open_fail: > > > > > + dma_release_channel(chan); > > > > > + > > > > > + return ret; > > > > > +} > > > > > + > > > > > +static int imx_pcm_close(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream) { > > > > > + if (substream) { > > > > > + snd_dma_free_pages(&substream->dma_buffer); > > > > > + substream->dma_buffer.area = NULL; > > > > > + substream->dma_buffer.addr = 0; > > > > > + } > > > > > + > > > > > + return snd_dmaengine_pcm_close_release_chan(substream); > > > > > +} > > > > > + > > > > > +static int imx_pcm_new(struct snd_soc_component *component, > > > > > + struct snd_soc_pcm_runtime *rtd) { > > > > > + struct snd_card *card = rtd->card->snd_card; > > > > > + > > > > > + return dma_coerce_mask_and_coherent(card->dev, > > > > > +DMA_BIT_MASK(32)); } > > > > > + > > > > > +static const struct snd_soc_component_driver imx_pcm_component = { > > > > > + .name = "imx-pcm-dma", > > > > > + .pcm_construct = imx_pcm_new, > > > > > + .open = imx_pcm_open, > > > > > + .close = imx_pcm_close, > > > > > + .hw_params = imx_pcm_hw_params, > > > > > + .hw_free = imx_pcm_hw_free, > > > > > + .trigger = imx_pcm_trigger, > > > > > + .pointer = imx_pcm_pointer, > > > > > +}; > > > > > + > > > > > +int imx_pcm_dma_init(struct platform_device *pdev, size_t size) { > > > > > + return devm_snd_soc_register_component(&pdev->dev, > > > > > + > > &imx_pcm_component, > > > > > +NULL, 0); > > > > > } > > > > > EXPORT_SYMBOL_GPL(imx_pcm_dma_init); > > > > > >

5 years, 1 month

[PATCH 1/3] dma-buf: Require VM_PFNMAP vma for mmap

by Daniel Vetter

tldr; DMA buffers aren't normal memory, expecting that you can use them like that (like calling get_user_pages works, or that they're accounting like any other normal memory) cannot be guaranteed. Since some userspace only runs on integrated devices, where all buffers are actually all resident system memory, there's a huge temptation to assume that a struct page is always present and useable like for any more pagecache backed mmap. This has the potential to result in a uapi nightmare. To stop this gap require that DMA buffer mmaps are VM_PFNMAP, which blocks get_user_pages and all the other struct page based infrastructure for everyone. In spirit this is the uapi counterpart to the kernel-internal CONFIG_DMABUF_DEBUG. Motivated by a recent patch which wanted to swich the system dma-buf heap to vm_insert_page instead of vm_insert_pfn. v2: Jason brought up that we also want to guarantee that all ptes have the pte_special flag set, to catch fast get_user_pages (on architectures that support this). Allowing VM_MIXEDMAP (like VM_SPECIAL does) would still allow vm_insert_page, but limiting to VM_PFNMAP will catch that. >From auditing the various functions to insert pfn pte entires (vm_insert_pfn_prot, remap_pfn_range and all it's callers like dma_mmap_wc) it looks like VM_PFNMAP is already required anyway, so this should be the correct flag to check for. References: https://lore.kernel.org/lkml/CAKMK7uHi+mG0z0HUmNt13QCCvutuRVjpcR0NjRL12k-Wb… Acked-by: Christian König <christian.koenig(a)amd.com> Cc: Jason Gunthorpe <jgg(a)ziepe.ca> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: John Stultz <john.stultz(a)linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: "Christian König" <christian.koenig(a)amd.com> Cc: linux-media(a)vger.kernel.org Cc: linaro-mm-sig(a)lists.linaro.org --- drivers/dma-buf/dma-buf.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index f264b70c383e..06cb1d2e9fdc 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -127,6 +127,7 @@ static struct file_system_type dma_buf_fs_type = { static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) { struct dma_buf *dmabuf; + int ret; if (!is_dma_buf_file(file)) return -EINVAL; @@ -142,7 +143,11 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) dmabuf->size >> PAGE_SHIFT) return -EINVAL; - return dmabuf->ops->mmap(dmabuf, vma); + ret = dmabuf->ops->mmap(dmabuf, vma); + + WARN_ON(!(vma->vm_flags & VM_PFNMAP)); + + return ret; } static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) @@ -1244,6 +1249,8 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) { + int ret; + if (WARN_ON(!dmabuf || !vma)) return -EINVAL; @@ -1264,7 +1271,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff; - return dmabuf->ops->mmap(dmabuf, vma); + ret = dmabuf->ops->mmap(dmabuf, vma); + + WARN_ON(!(vma->vm_flags & VM_PFNMAP)); + + return ret; } EXPORT_SYMBOL_GPL(dma_buf_mmap); -- 2.31.0

5 years, 1 month

Re: [Linaro-mm-sig] [PATCH RFC 1/3] fpga: region: Add fpga-region property 'fpga-config-from-dmabuf'

by Rob Herring

On Fri, Apr 02, 2021 at 02:39:31PM +0530, Nava kishore Manne wrote: > Add "fpga-config-from-dmabuf" property to allow the bitstream > configuration from pre-allocated dma-buffer. > > Signed-off-by: Nava kishore Manne <nava.manne(a)xilinx.com> > --- > Documentation/devicetree/bindings/fpga/fpga-region.txt | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/Documentation/devicetree/bindings/fpga/fpga-region.txt b/Documentation/devicetree/bindings/fpga/fpga-region.txt > index 969ca53bb65e..c573cf258d60 100644 > --- a/Documentation/devicetree/bindings/fpga/fpga-region.txt > +++ b/Documentation/devicetree/bindings/fpga/fpga-region.txt > @@ -177,6 +177,8 @@ Optional properties: > it indicates that the FPGA has already been programmed with this image. > If this property is in an overlay targeting a FPGA region, it is a > request to program the FPGA with that image. > +- fpga-config-from-dmabuf : boolean, set if the FPGA configured done from the > + pre-allocated dma-buffer. Sounds like an implementation detail of the OS. Doesn't belong in DT. Rob > - fpga-bridges : should contain a list of phandles to FPGA Bridges that must be > controlled during FPGA programming along with the parent FPGA bridge. > This property is optional if the FPGA Manager handles the bridges. > -- > 2.18.0 >

5 years, 1 month

[PATCH] drm/syncobj: use newly allocated stub fences

by David Stevens

From: David Stevens <stevensd(a)chromium.org> Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 28 ++++++++++++++++++++-------- include/linux/dma-fence.h | 1 + 3 files changed, 53 insertions(+), 9 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..6081eb962490 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); static DEFINE_SPINLOCK(dma_fence_stub_lock); static struct dma_fence dma_fence_stub; +struct drm_fence_private_stub { + struct dma_fence base; + spinlock_t lock; +}; + /* * fence context counter: each execution context should have its own * fence context, this allows checking if fences belong to the same @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct drm_fence_private_stub *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, + &dma_fence_stub_ops, + &fence->lock, + 0, 0); + dma_fence_signal(&fence->base); + + return &fence->base; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..c6125e57ae37 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,15 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + if (IS_ERR(fence)) + return PTR_ERR(fence); - drm_syncobj_replace_fence(syncobj, fence); - dma_fence_put(fence); + drm_syncobj_replace_fence(syncobj, fence); + dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +472,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +483,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1331,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.31.0.208.g409f899ff0-goog

5 years, 1 month

[PATCH v3] drm/syncobj: use newly allocated stub fences

by David Stevens

From: David Stevens <stevensd(a)chromium.org> Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- v2 -> v3: - reuse the static stub spinlock v1 -> v2: - checkpatch style fixes drivers/dma-buf/dma-fence.c | 27 ++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 25 +++++++++++++++++++------ include/linux/dma-fence.h | 1 + 3 files changed, 46 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..ce0f5eff575d 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -123,7 +123,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +143,29 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct dma_fence *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + dma_fence_init(fence, + &dma_fence_stub_ops, + &dma_fence_stub_lock, + 0, 0); + dma_fence_signal(fence); + + return fence; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..a54aa850d143 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,16 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + + if (IS_ERR(fence)) + return PTR_ERR(fence); drm_syncobj_replace_fence(syncobj, fence); dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +473,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +484,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1332,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.31.0.208.g409f899ff0-goog

5 years, 1 month

[PATCH v2] drm/syncobj: use newly allocated stub fences

by David Stevens

From: David Stevens <stevensd(a)chromium.org> Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- v1 -> v2: - checkpatch style fixes drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 25 +++++++++++++++++++------ include/linux/dma-fence.h | 1 + 3 files changed, 52 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..6081eb962490 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); static DEFINE_SPINLOCK(dma_fence_stub_lock); static struct dma_fence dma_fence_stub; +struct drm_fence_private_stub { + struct dma_fence base; + spinlock_t lock; +}; + /* * fence context counter: each execution context should have its own * fence context, this allows checking if fences belong to the same @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct drm_fence_private_stub *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, + &dma_fence_stub_ops, + &fence->lock, + 0, 0); + dma_fence_signal(&fence->base); + + return &fence->base; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..a54aa850d143 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,16 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + + if (IS_ERR(fence)) + return PTR_ERR(fence); drm_syncobj_replace_fence(syncobj, fence); dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +473,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +484,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1332,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.31.0.208.g409f899ff0-goog

5 years, 1 month

[PATCH] Revert "drm/syncobj: use dma_fence_get_stub"

by David Stevens

From: David Stevens <stevensd(a)chromium.org> This reverts commit 86bbd89d5da66fe760049ad3f04adc407ec0c4d6. Using the singleton stub fence in drm_syncobj_assign_null_handle means that all syncobjs created in an already signaled state or any syncobjs signaled by userspace will reference the singleton fence when exported to a sync_file. If those sync_files are queried with SYNC_IOC_FILE_INFO, then the timestamp_ns value returned will correspond to whenever the singleton stub fence was first initialized. This can break the ability of userspace to use timestamps of these fences, as the singleton stub fence's timestamp bears no relationship to any meaningful event. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- drivers/gpu/drm/drm_syncobj.c | 58 ++++++++++++++++++++++++++--------- 1 file changed, 44 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..7cc11f1a83f4 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -211,6 +211,21 @@ struct syncobj_wait_entry { static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj, struct syncobj_wait_entry *wait); +struct drm_syncobj_stub_fence { + struct dma_fence base; + spinlock_t lock; +}; + +static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence) +{ + return "syncobjstub"; +} + +static const struct dma_fence_ops drm_syncobj_stub_fence_ops = { + .get_driver_name = drm_syncobj_stub_fence_get_name, + .get_timeline_name = drm_syncobj_stub_fence_get_name, +}; + /** * drm_syncobj_find - lookup and reference a sync object. * @file_private: drm file private pointer @@ -344,18 +359,24 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, } EXPORT_SYMBOL(drm_syncobj_replace_fence); -/** - * drm_syncobj_assign_null_handle - assign a stub fence to the sync object - * @syncobj: sync object to assign the fence on - * - * Assign a already signaled stub fence to the sync object. - */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct drm_syncobj_stub_fence *fence; - drm_syncobj_replace_fence(syncobj, fence); - dma_fence_put(fence); + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return -ENOMEM; + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, &drm_syncobj_stub_fence_ops, + &fence->lock, 0, 0); + dma_fence_signal(&fence->base); + + drm_syncobj_replace_fence(syncobj, &fence->base); + + dma_fence_put(&fence->base); + + return 0; } /* 5s default for wait submission */ @@ -469,6 +490,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +501,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1349,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); -- 2.31.0.208.g409f899ff0-goog

5 years, 1 month

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