From 40ddacf2dda952e0f33b40d850bf5f7403bdbe0f Mon Sep 17 00:00:00 2001 From: Leon Romanovsky Date: Tue, 10 Jul 2018 13:31:48 +0300 Subject: [PATCH] RDMA/umem: Don't hold mmap_sem for too long 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 Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/umem.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 498f59bb4989..abe9924baf7c 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -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(¤t->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(¤t->mm->mmap_sem); + current->mm->pinned_vm += npages; + if ((current->mm->pinned_vm > lock_limit) && !capable(CAP_IPC_LOCK)) { + up_write(¤t->mm->mmap_sem); ret = -ENOMEM; goto out; } + up_write(¤t->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(¤t->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(¤t->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(¤t->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(¤t->mm->mmap_sem); + current->mm->pinned_vm -= ib_umem_num_pages(umem); + up_write(¤t->mm->mmap_sem); if (need_release) __ib_umem_release(context->device, umem, 0); kfree(umem); - } else - current->mm->pinned_vm = locked; + } - up_write(¤t->mm->mmap_sem); if (vma_list) free_page((unsigned long) vma_list); free_page((unsigned long) page_list); -- 2.11.0