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uacce: Remove mm_exit() op

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The mm_exit() op will be removed from the SVA API. When a process dies
and its mm goes away, the IOMMU driver won't notify device drivers
anymore. Drivers should expect to handle a lot more aborted DMA. On the
upside, it does greatly simplify the queue management.

The uacce_mm struct, that tracks all queues bound to an mm, was only
used by the mm_exit() callback. Remove it.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://lore.kernel.org/r/20200423125329.782066-2-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Jean-Philippe Brucker 2020-04-23 14:53:28 +02:00 committed by Joerg Roedel
parent da656a0425
commit fb01562e5a
2 changed files with 53 additions and 157 deletions
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176
drivers/misc/uacce/uacce.c
View File

@ -90,109 +90,39 @@ static long uacce_fops_compat_ioctl(struct file *filep,
} }
#endif #endif
static int uacce_sva_exit(struct device *dev, struct iommu_sva *handle, static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
void *data)
{ {
struct uacce_mm *uacce_mm = data; int pasid;
struct uacce_queue *q; struct iommu_sva *handle;
/* if (!(uacce->flags & UACCE_DEV_SVA))
* No new queue can be added concurrently because no caller can have a return 0;
* reference to this mm. But there may be concurrent calls to
* uacce_mm_put(), so we need the lock.
*/
mutex_lock(&uacce_mm->lock);
list_for_each_entry(q, &uacce_mm->queues, list)
uacce_put_queue(q);
uacce_mm->mm = NULL;
mutex_unlock(&uacce_mm->lock);
handle = iommu_sva_bind_device(uacce->parent, current->mm, NULL);
if (IS_ERR(handle))
return PTR_ERR(handle);
pasid = iommu_sva_get_pasid(handle);
if (pasid == IOMMU_PASID_INVALID) {
iommu_sva_unbind_device(handle);
return -ENODEV;
}
q->handle = handle;
q->pasid = pasid;
return 0; return 0;
} }
static struct iommu_sva_ops uacce_sva_ops = { static void uacce_unbind_queue(struct uacce_queue *q)
.mm_exit = uacce_sva_exit,
};
static struct uacce_mm *uacce_mm_get(struct uacce_device *uacce,
struct uacce_queue *q,
struct mm_struct *mm)
{ {
struct uacce_mm *uacce_mm = NULL; if (!q->handle)
struct iommu_sva *handle = NULL; return;
int ret; iommu_sva_unbind_device(q->handle);
q->handle = NULL;
lockdep_assert_held(&uacce->mm_lock);
list_for_each_entry(uacce_mm, &uacce->mm_list, list) {
if (uacce_mm->mm == mm) {
mutex_lock(&uacce_mm->lock);
list_add(&q->list, &uacce_mm->queues);
mutex_unlock(&uacce_mm->lock);
return uacce_mm;
}
}
uacce_mm = kzalloc(sizeof(*uacce_mm), GFP_KERNEL);
if (!uacce_mm)
return NULL;
if (uacce->flags & UACCE_DEV_SVA) {
/*
* Safe to pass an incomplete uacce_mm, since mm_exit cannot
* fire while we hold a reference to the mm.
*/
handle = iommu_sva_bind_device(uacce->parent, mm, uacce_mm);
if (IS_ERR(handle))
goto err_free;
ret = iommu_sva_set_ops(handle, &uacce_sva_ops);
if (ret)
goto err_unbind;
uacce_mm->pasid = iommu_sva_get_pasid(handle);
if (uacce_mm->pasid == IOMMU_PASID_INVALID)
goto err_unbind;
}
uacce_mm->mm = mm;
uacce_mm->handle = handle;
INIT_LIST_HEAD(&uacce_mm->queues);
mutex_init(&uacce_mm->lock);
list_add(&q->list, &uacce_mm->queues);
list_add(&uacce_mm->list, &uacce->mm_list);
return uacce_mm;
err_unbind:
if (handle)
iommu_sva_unbind_device(handle);
err_free:
kfree(uacce_mm);
return NULL;
}
static void uacce_mm_put(struct uacce_queue *q)
{
struct uacce_mm *uacce_mm = q->uacce_mm;
lockdep_assert_held(&q->uacce->mm_lock);
mutex_lock(&uacce_mm->lock);
list_del(&q->list);
mutex_unlock(&uacce_mm->lock);
if (list_empty(&uacce_mm->queues)) {
if (uacce_mm->handle)
iommu_sva_unbind_device(uacce_mm->handle);
list_del(&uacce_mm->list);
kfree(uacce_mm);
}
} }
static int uacce_fops_open(struct inode *inode, struct file *filep) static int uacce_fops_open(struct inode *inode, struct file *filep)
{ {
struct uacce_mm *uacce_mm = NULL;
struct uacce_device *uacce; struct uacce_device *uacce;
struct uacce_queue *q; struct uacce_queue *q;
int ret = 0; int ret = 0;
@ -205,21 +135,16 @@ static int uacce_fops_open(struct inode *inode, struct file *filep)
if (!q) if (!q)
return -ENOMEM; return -ENOMEM;
mutex_lock(&uacce->mm_lock); ret = uacce_bind_queue(uacce, q);
uacce_mm = uacce_mm_get(uacce, q, current->mm); if (ret)
mutex_unlock(&uacce->mm_lock);
if (!uacce_mm) {
ret = -ENOMEM;
goto out_with_mem; goto out_with_mem;
}
q->uacce = uacce; q->uacce = uacce;
q->uacce_mm = uacce_mm;
if (uacce->ops->get_queue) { if (uacce->ops->get_queue) {
ret = uacce->ops->get_queue(uacce, uacce_mm->pasid, q); ret = uacce->ops->get_queue(uacce, q->pasid, q);
if (ret < 0) if (ret < 0)
goto out_with_mm; goto out_with_bond;
} }
init_waitqueue_head(&q->wait); init_waitqueue_head(&q->wait);
@ -227,12 +152,14 @@ static int uacce_fops_open(struct inode *inode, struct file *filep)
uacce->inode = inode; uacce->inode = inode;
q->state = UACCE_Q_INIT; q->state = UACCE_Q_INIT;
mutex_lock(&uacce->queues_lock);
list_add(&q->list, &uacce->queues);
mutex_unlock(&uacce->queues_lock);
return 0; return 0;
out_with_mm: out_with_bond:
mutex_lock(&uacce->mm_lock); uacce_unbind_queue(q);
uacce_mm_put(q);
mutex_unlock(&uacce->mm_lock);
out_with_mem: out_with_mem:
kfree(q); kfree(q);
return ret; return ret;
@ -241,14 +168,12 @@ static int uacce_fops_open(struct inode *inode, struct file *filep)
static int uacce_fops_release(struct inode *inode, struct file *filep) static int uacce_fops_release(struct inode *inode, struct file *filep)
{ {
struct uacce_queue *q = filep->private_data; struct uacce_queue *q = filep->private_data;
struct uacce_device *uacce = q->uacce;
mutex_lock(&q->uacce->queues_lock);
list_del(&q->list);
mutex_unlock(&q->uacce->queues_lock);
uacce_put_queue(q); uacce_put_queue(q);
uacce_unbind_queue(q);
mutex_lock(&uacce->mm_lock);
uacce_mm_put(q);
mutex_unlock(&uacce->mm_lock);
kfree(q); kfree(q);
return 0; return 0;
@ -513,8 +438,8 @@ struct uacce_device *uacce_alloc(struct device *parent,
if (ret < 0) if (ret < 0)
goto err_with_uacce; goto err_with_uacce;
INIT_LIST_HEAD(&uacce->mm_list); INIT_LIST_HEAD(&uacce->queues);
mutex_init(&uacce->mm_lock); mutex_init(&uacce->queues_lock);
device_initialize(&uacce->dev); device_initialize(&uacce->dev);
uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id); uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id);
uacce->dev.class = uacce_class; uacce->dev.class = uacce_class;
@ -561,8 +486,7 @@ EXPORT_SYMBOL_GPL(uacce_register);
*/ */
void uacce_remove(struct uacce_device *uacce) void uacce_remove(struct uacce_device *uacce)
{ {
struct uacce_mm *uacce_mm; struct uacce_queue *q, *next_q;
struct uacce_queue *q;
if (!uacce) if (!uacce)
return; return;
@ -574,24 +498,12 @@ void uacce_remove(struct uacce_device *uacce)
unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1); unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1);
/* ensure no open queue remains */ /* ensure no open queue remains */
mutex_lock(&uacce->mm_lock); mutex_lock(&uacce->queues_lock);
list_for_each_entry(uacce_mm, &uacce->mm_list, list) { list_for_each_entry_safe(q, next_q, &uacce->queues, list) {
/* uacce_put_queue(q);
* We don't take the uacce_mm->lock here. Since we hold the uacce_unbind_queue(q);
* device's mm_lock, no queue can be added to or removed from
* this uacce_mm. We may run concurrently with mm_exit, but
* uacce_put_queue() is serialized and iommu_sva_unbind_device()
* waits for the lock that mm_exit is holding.
*/
list_for_each_entry(q, &uacce_mm->queues, list)
uacce_put_queue(q);
if (uacce->flags & UACCE_DEV_SVA) {
iommu_sva_unbind_device(uacce_mm->handle);
uacce_mm->handle = NULL;
}
} }
mutex_unlock(&uacce->mm_lock); mutex_unlock(&uacce->queues_lock);
/* disable sva now since no opened queues */ /* disable sva now since no opened queues */
if (uacce->flags & UACCE_DEV_SVA) if (uacce->flags & UACCE_DEV_SVA)

34
include/linux/uacce.h
View File

@ -68,19 +68,21 @@ enum uacce_q_state {
* @uacce: pointer to uacce * @uacce: pointer to uacce
* @priv: private pointer * @priv: private pointer
* @wait: wait queue head * @wait: wait queue head
* @list: index into uacce_mm * @list: index into uacce queues list
* @uacce_mm: the corresponding mm
* @qfrs: pointer of qfr regions * @qfrs: pointer of qfr regions
* @state: queue state machine * @state: queue state machine
* @pasid: pasid associated to the mm
* @handle: iommu_sva handle returned by iommu_sva_bind_device()
*/ */
struct uacce_queue { struct uacce_queue {
struct uacce_device *uacce; struct uacce_device *uacce;
void *priv; void *priv;
wait_queue_head_t wait; wait_queue_head_t wait;
struct list_head list; struct list_head list;
struct uacce_mm *uacce_mm;
struct uacce_qfile_region *qfrs[UACCE_MAX_REGION]; struct uacce_qfile_region *qfrs[UACCE_MAX_REGION];
enum uacce_q_state state; enum uacce_q_state state;
int pasid;
struct iommu_sva *handle;
}; };
/** /**
@ -96,8 +98,8 @@ struct uacce_queue {
* @cdev: cdev of the uacce * @cdev: cdev of the uacce
* @dev: dev of the uacce * @dev: dev of the uacce
* @priv: private pointer of the uacce * @priv: private pointer of the uacce
* @mm_list: list head of uacce_mm->list * @queues: list of queues
* @mm_lock: lock for mm_list * @queues_lock: lock for queues list
* @inode: core vfs * @inode: core vfs
*/ */
struct uacce_device { struct uacce_device {
@ -112,27 +114,9 @@ struct uacce_device {
struct cdev *cdev; struct cdev *cdev;
struct device dev; struct device dev;
void *priv; void *priv;
struct list_head mm_list;
struct mutex mm_lock;
struct inode *inode;
};
/**
* struct uacce_mm - keep track of queues bound to a process
* @list: index into uacce_device
* @queues: list of queues
* @mm: the mm struct
* @lock: protects the list of queues
* @pasid: pasid of the uacce_mm
* @handle: iommu_sva handle return from iommu_sva_bind_device
*/
struct uacce_mm {
struct list_head list;
struct list_head queues; struct list_head queues;
struct mm_struct *mm; struct mutex queues_lock;
struct mutex lock; struct inode *inode;
int pasid;
struct iommu_sva *handle;
}; };
#if IS_ENABLED(CONFIG_UACCE) #if IS_ENABLED(CONFIG_UACCE)