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RDMA/umem: Don't hold mmap_sem for too long

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DMA mapping is time consuming operation and doesn't need to be performed
with mmap_sem semaphore is held.

The semaphore only needs to be held for accounting and get_user_pages
related activities.

Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Leon Romanovsky 2018-07-10 13:31:48 +03:00 committed by Jason Gunthorpe
parent 6869e0004f
commit 40ddacf2dd
1 changed files with 14 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

24
drivers/infiniband/core/umem.c
View file

@ -84,7 +84,6 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
struct ib_umem *umem;
struct page **page_list;
struct vm_area_struct **vma_list;
unsigned long locked;
unsigned long lock_limit;
unsigned long cur_base;
unsigned long npages;
@ -149,15 +148,16 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
npages = ib_umem_num_pages(umem);
down_write(&current->mm->mmap_sem);
locked = npages + current->mm->pinned_vm;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
down_write(&current->mm->mmap_sem);
current->mm->pinned_vm += npages;
if ((current->mm->pinned_vm > lock_limit) && !capable(CAP_IPC_LOCK)) {
up_write(&current->mm->mmap_sem);
ret = -ENOMEM;
goto out;
}
up_write(&current->mm->mmap_sem);
cur_base = addr & PAGE_MASK;
@ -176,14 +176,16 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
need_release = 1;
sg_list_start = umem->sg_head.sgl;
down_read(&current->mm->mmap_sem);
while (npages) {
ret = get_user_pages_longterm(cur_base,
min_t(unsigned long, npages,
PAGE_SIZE / sizeof (struct page *)),
gup_flags, page_list, vma_list);
if (ret < 0)
if (ret < 0) {
up_read(&current->mm->mmap_sem);
goto out;
}
umem->npages += ret;
cur_base += ret * PAGE_SIZE;
@ -199,6 +201,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
/* preparing for next loop */
sg_list_start = sg;
}
up_read(&current->mm->mmap_sem);
umem->nmap = ib_dma_map_sg_attrs(context->device,
umem->sg_head.sgl,
@ -215,13 +218,14 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
out:
if (ret < 0) {
down_write(&current->mm->mmap_sem);
current->mm->pinned_vm -= ib_umem_num_pages(umem);
up_write(&current->mm->mmap_sem);
if (need_release)
__ib_umem_release(context->device, umem, 0);
kfree(umem);
} else
current->mm->pinned_vm = locked;
}
up_write(&current->mm->mmap_sem);
if (vma_list)
free_page((unsigned long) vma_list);
free_page((unsigned long) page_list);