lkml.org 
[lkml]   [2019]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH 15/16] drm/etnaviv: use ktime_t for timeouts
    From
    Date
    Am Freitag, den 08.11.2019, 22:32 +0100 schrieb Arnd Bergmann:
    > struct timespec is being removed from the kernel because it often leads
    > to code that is not y2038-safe.
    >
    > In the etnaviv driver, monotonic timestamps are used, which do not suffer
    > from overflow, but using ktime_t still leads to better code overall.
    >
    > The conversion is straightforward for the most part, except for
    > etnaviv_timeout_to_jiffies(), which needs to handle arguments larger
    > than MAX_JIFFY_OFFSET on 32-bit architectures.
    >
    > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    > ---
    > drivers/gpu/drm/etnaviv/etnaviv_drv.c | 19 +++++++++----------
    > drivers/gpu/drm/etnaviv/etnaviv_drv.h | 21 +++++++++------------
    > drivers/gpu/drm/etnaviv/etnaviv_gem.c | 5 ++---
    > drivers/gpu/drm/etnaviv/etnaviv_gem.h | 2 +-
    > drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 4 ++--
    > drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 4 ++--
    > 6 files changed, 25 insertions(+), 30 deletions(-)
    >
    > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
    > index 1f9c01be40d7..1250c5e06329 100644
    > --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
    > +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
    > @@ -282,16 +282,13 @@ static int etnaviv_ioctl_gem_new(struct drm_device *dev, void *data,
    > args->flags, &args->handle);
    > }
    >
    > -#define TS(t) ((struct timespec){ \
    > - .tv_sec = (t).tv_sec, \
    > - .tv_nsec = (t).tv_nsec \
    > -})
    > -
    > static int etnaviv_ioctl_gem_cpu_prep(struct drm_device *dev, void *data,
    > struct drm_file *file)
    > {
    > struct drm_etnaviv_gem_cpu_prep *args = data;
    > struct drm_gem_object *obj;
    > + ktime_t timeout = ktime_set(args->timeout.tv_sec,
    > + args->timeout.tv_nsec);
    > int ret;
    >
    > if (args->op & ~(ETNA_PREP_READ | ETNA_PREP_WRITE | ETNA_PREP_NOSYNC))
    > @@ -301,7 +298,7 @@ static int etnaviv_ioctl_gem_cpu_prep(struct drm_device *dev, void *data,
    > if (!obj)
    > return -ENOENT;
    >
    > - ret = etnaviv_gem_cpu_prep(obj, args->op, &TS(args->timeout));
    > + ret = etnaviv_gem_cpu_prep(obj, args->op, timeout);
    >
    > drm_gem_object_put_unlocked(obj);
    >
    > @@ -354,7 +351,8 @@ static int etnaviv_ioctl_wait_fence(struct drm_device *dev, void *data,
    > {
    > struct drm_etnaviv_wait_fence *args = data;
    > struct etnaviv_drm_private *priv = dev->dev_private;
    > - struct timespec *timeout = &TS(args->timeout);
    > + ktime_t timeout = ktime_set(args->timeout.tv_sec,
    > + args->timeout.tv_nsec);
    > struct etnaviv_gpu *gpu;
    >
    > if (args->flags & ~(ETNA_WAIT_NONBLOCK))
    > @@ -368,7 +366,7 @@ static int etnaviv_ioctl_wait_fence(struct drm_device *dev, void *data,
    > return -ENXIO;
    >
    > if (args->flags & ETNA_WAIT_NONBLOCK)
    > - timeout = NULL;
    > + timeout = ktime_set(0, 0);

    This is a change in behavior, as far as I can see. After this change
    the called internal function is not able to differentiate between a
    NONBLOCK call and a blocking call with 0 timeout. The difference being
    that on a busy object the NONBLOCK call will return -EBUSY, while a
    blocking call will return -ETIMEDOUT.

    But then CLOCK_MONOTONIC starts at 0 and should not never wrap, right?
    If that's the case then we should never encounter a genuine 0 timeout
    and this change would be okay.

    Regards,
    Lucas
    >
    > return etnaviv_gpu_wait_fence_interruptible(gpu, args->fence,
    > timeout);
    > @@ -403,7 +401,8 @@ static int etnaviv_ioctl_gem_wait(struct drm_device *dev, void *data,
    > {
    > struct etnaviv_drm_private *priv = dev->dev_private;
    > struct drm_etnaviv_gem_wait *args = data;
    > - struct timespec *timeout = &TS(args->timeout);
    > + ktime_t timeout = ktime_set(args->timeout.tv_sec,
    > + args->timeout.tv_nsec);
    > struct drm_gem_object *obj;
    > struct etnaviv_gpu *gpu;
    > int ret;
    > @@ -423,7 +422,7 @@ static int etnaviv_ioctl_gem_wait(struct drm_device *dev, void *data,
    > return -ENOENT;
    >
    > if (args->flags & ETNA_WAIT_NONBLOCK)
    > - timeout = NULL;
    > + timeout = ktime_set(0, 0);
    >
    > ret = etnaviv_gem_wait_bo(gpu, obj, timeout);
    >
    > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
    > index 32cfa5a48d42..57a4e247bbcf 100644
    > --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h
    > +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
    > @@ -60,8 +60,7 @@ struct drm_gem_object *etnaviv_gem_prime_import_sg_table(struct drm_device *dev,
    > int etnaviv_gem_prime_pin(struct drm_gem_object *obj);
    > void etnaviv_gem_prime_unpin(struct drm_gem_object *obj);
    > void *etnaviv_gem_vmap(struct drm_gem_object *obj);
    > -int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op,
    > - struct timespec *timeout);
    > +int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op, ktime_t timeout);
    > int etnaviv_gem_cpu_fini(struct drm_gem_object *obj);
    > void etnaviv_gem_free_object(struct drm_gem_object *obj);
    > int etnaviv_gem_new_handle(struct drm_device *dev, struct drm_file *file,
    > @@ -106,22 +105,20 @@ static inline size_t size_vstruct(size_t nelem, size_t elem_size, size_t base)
    > * We need to calculate the timeout in terms of number of jiffies
    > * between the specified timeout and the current CLOCK_MONOTONIC time.
    > */
    > -static inline unsigned long etnaviv_timeout_to_jiffies(
    > - const struct timespec *timeout)
    > +static inline unsigned long etnaviv_timeout_to_jiffies(ktime_t timeout)
    > {
    > - struct timespec64 ts, to;
    > -
    > - to = timespec_to_timespec64(*timeout);
    > -
    > - ktime_get_ts64(&ts);
    > + s64 remain = ktime_to_ns(ktime_sub(timeout, ktime_get()));
    >
    > /* timeouts before "now" have already expired */
    > - if (timespec64_compare(&to, &ts) <= 0)
    > + if (remain < 0)
    > return 0;
    >
    > - ts = timespec64_sub(to, ts);
    > +#ifndef CONFIG_64BIT
    > + if (remain > ((s64)MAX_JIFFY_OFFSET * NSEC_PER_SEC / HZ))
    > + return MAX_JIFFY_OFFSET;
    > +#endif
    >
    > - return timespec64_to_jiffies(&ts);
    > + return nsecs_to_jiffies(remain);
    > }
    >
    > #endif /* __ETNAVIV_DRV_H__ */
    > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
    > index cb1faaac380a..febe5196788e 100644
    > --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
    > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
    > @@ -372,8 +372,7 @@ static inline enum dma_data_direction etnaviv_op_to_dma_dir(u32 op)
    > return DMA_BIDIRECTIONAL;
    > }
    >
    > -int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op,
    > - struct timespec *timeout)
    > +int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op, ktime_t timeout)
    > {
    > struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
    > struct drm_device *dev = obj->dev;
    > @@ -431,7 +430,7 @@ int etnaviv_gem_cpu_fini(struct drm_gem_object *obj)
    > }
    >
    > int etnaviv_gem_wait_bo(struct etnaviv_gpu *gpu, struct drm_gem_object *obj,
    > - struct timespec *timeout)
    > + ktime_t timeout)
    > {
    > struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
    >
    > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.h b/drivers/gpu/drm/etnaviv/etnaviv_gem.h
    > index d6270acce619..a3461a554a6c 100644
    > --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.h
    > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.h
    > @@ -112,7 +112,7 @@ struct etnaviv_gem_submit {
    > void etnaviv_submit_put(struct etnaviv_gem_submit * submit);
    >
    > int etnaviv_gem_wait_bo(struct etnaviv_gpu *gpu, struct drm_gem_object *obj,
    > - struct timespec *timeout);
    > + ktime_t timeout);
    > int etnaviv_gem_new_private(struct drm_device *dev, size_t size, u32 flags,
    > const struct etnaviv_gem_ops *ops, struct etnaviv_gem_object **res);
    > void etnaviv_gem_obj_add(struct drm_device *dev, struct drm_gem_object *obj);
    > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
    > index d47d1a8e0219..e42b1c4d902c 100644
    > --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
    > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
    > @@ -1132,7 +1132,7 @@ static void event_free(struct etnaviv_gpu *gpu, unsigned int event)
    > * Cmdstream submission/retirement:
    > */
    > int etnaviv_gpu_wait_fence_interruptible(struct etnaviv_gpu *gpu,
    > - u32 id, struct timespec *timeout)
    > + u32 id, ktime_t timeout)
    > {
    > struct dma_fence *fence;
    > int ret;
    > @@ -1179,7 +1179,7 @@ int etnaviv_gpu_wait_fence_interruptible(struct etnaviv_gpu *gpu,
    > * that lock in this function while waiting.
    > */
    > int etnaviv_gpu_wait_obj_inactive(struct etnaviv_gpu *gpu,
    > - struct etnaviv_gem_object *etnaviv_obj, struct timespec *timeout)
    > + struct etnaviv_gem_object *etnaviv_obj, ktime_t timeout)
    > {
    > unsigned long remaining;
    > long ret;
    > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
    > index 8f9bd4edc96a..6d352a435427 100644
    > --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
    > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
    > @@ -169,9 +169,9 @@ int etnaviv_gpu_debugfs(struct etnaviv_gpu *gpu, struct seq_file *m);
    > void etnaviv_gpu_recover_hang(struct etnaviv_gpu *gpu);
    > void etnaviv_gpu_retire(struct etnaviv_gpu *gpu);
    > int etnaviv_gpu_wait_fence_interruptible(struct etnaviv_gpu *gpu,
    > - u32 fence, struct timespec *timeout);
    > + u32 fence, ktime_t timeout);
    > int etnaviv_gpu_wait_obj_inactive(struct etnaviv_gpu *gpu,
    > - struct etnaviv_gem_object *etnaviv_obj, struct timespec *timeout);
    > + struct etnaviv_gem_object *etnaviv_obj, ktime_t timeout);
    > struct dma_fence *etnaviv_gpu_submit(struct etnaviv_gem_submit *submit);
    > int etnaviv_gpu_pm_get_sync(struct etnaviv_gpu *gpu);
    > void etnaviv_gpu_pm_put(struct etnaviv_gpu *gpu);

    \
     
     \ /
      Last update: 2019-11-09 00:06    [W:3.450 / U:0.072 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site