forked from Minki/linux
drivers/IB,core: reduce scope of mmap_sem
ib_umem_get() uses gup_longterm() and relies on the lock to stabilze the vma_list, so we cannot really get rid of mmap_sem altogether, but now that the counter is atomic, we can get of some complexity that mmap_sem brings with only pinned_vm. Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
parent
8ea1f989aa
commit
b95df5e3e4
@ -165,15 +165,12 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr,
|
||||
|
||||
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
|
||||
|
||||
down_write(&mm->mmap_sem);
|
||||
new_pinned = atomic64_read(&mm->pinned_vm) + npages;
|
||||
new_pinned = atomic64_add_return(npages, &mm->pinned_vm);
|
||||
if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) {
|
||||
up_write(&mm->mmap_sem);
|
||||
atomic64_sub(npages, &mm->pinned_vm);
|
||||
ret = -ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
atomic64_set(&mm->pinned_vm, new_pinned);
|
||||
up_write(&mm->mmap_sem);
|
||||
|
||||
cur_base = addr & PAGE_MASK;
|
||||
|
||||
@ -233,9 +230,7 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr,
|
||||
umem_release:
|
||||
__ib_umem_release(context->device, umem, 0);
|
||||
vma:
|
||||
down_write(&mm->mmap_sem);
|
||||
atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm);
|
||||
up_write(&mm->mmap_sem);
|
||||
out:
|
||||
if (vma_list)
|
||||
free_page((unsigned long) vma_list);
|
||||
@ -258,25 +253,12 @@ static void __ib_umem_release_tail(struct ib_umem *umem)
|
||||
kfree(umem);
|
||||
}
|
||||
|
||||
static void ib_umem_release_defer(struct work_struct *work)
|
||||
{
|
||||
struct ib_umem *umem = container_of(work, struct ib_umem, work);
|
||||
|
||||
down_write(&umem->owning_mm->mmap_sem);
|
||||
atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm);
|
||||
up_write(&umem->owning_mm->mmap_sem);
|
||||
|
||||
__ib_umem_release_tail(umem);
|
||||
}
|
||||
|
||||
/**
|
||||
* ib_umem_release - release memory pinned with ib_umem_get
|
||||
* @umem: umem struct to release
|
||||
*/
|
||||
void ib_umem_release(struct ib_umem *umem)
|
||||
{
|
||||
struct ib_ucontext *context = umem->context;
|
||||
|
||||
if (umem->is_odp) {
|
||||
ib_umem_odp_release(to_ib_umem_odp(umem));
|
||||
__ib_umem_release_tail(umem);
|
||||
@ -285,26 +267,7 @@ void ib_umem_release(struct ib_umem *umem)
|
||||
|
||||
__ib_umem_release(umem->context->device, umem, 1);
|
||||
|
||||
/*
|
||||
* We may be called with the mm's mmap_sem already held. This
|
||||
* can happen when a userspace munmap() is the call that drops
|
||||
* the last reference to our file and calls our release
|
||||
* method. If there are memory regions to destroy, we'll end
|
||||
* up here and not be able to take the mmap_sem. In that case
|
||||
* we defer the vm_locked accounting a workqueue.
|
||||
*/
|
||||
if (context->closing) {
|
||||
if (!down_write_trylock(&umem->owning_mm->mmap_sem)) {
|
||||
INIT_WORK(&umem->work, ib_umem_release_defer);
|
||||
queue_work(ib_wq, &umem->work);
|
||||
return;
|
||||
}
|
||||
} else {
|
||||
down_write(&umem->owning_mm->mmap_sem);
|
||||
}
|
||||
atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm);
|
||||
up_write(&umem->owning_mm->mmap_sem);
|
||||
|
||||
__ib_umem_release_tail(umem);
|
||||
}
|
||||
EXPORT_SYMBOL(ib_umem_release);
|
||||
|
Loading…
Reference in New Issue
Block a user