From 8ea1f989aa07a095cbf4aabbf9be7c3a18ce31bf Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Wed, 6 Feb 2019 09:59:19 -0800 Subject: [PATCH] drivers/IB,usnic: reduce scope of mmap_sem usnic_uiom_get_pages() uses gup_longterm() so we cannot really get rid of mmap_sem altogether in the driver, but we can get rid of some complexity that mmap_sem brings with only pinned_vm. We can get rid of the wq altogether as we no longer need to defer work to unpin pages as the counter is now atomic. We also share the lock. Acked-by: Parvi Kaustubhi Reviewed-by: Ira Weiny Signed-off-by: Davidlohr Bueso Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/usnic/usnic_ib_main.c | 2 - drivers/infiniband/hw/usnic/usnic_uiom.c | 58 +++-------------------------- drivers/infiniband/hw/usnic/usnic_uiom.h | 1 - 3 files changed, 6 insertions(+), 55 deletions(-) diff --git a/drivers/infiniband/hw/usnic/usnic_ib_main.c b/drivers/infiniband/hw/usnic/usnic_ib_main.c index c4a4cfe..577d930 100644 --- a/drivers/infiniband/hw/usnic/usnic_ib_main.c +++ b/drivers/infiniband/hw/usnic/usnic_ib_main.c @@ -684,7 +684,6 @@ out_unreg_netdev_notifier: out_pci_unreg: pci_unregister_driver(&usnic_ib_pci_driver); out_umem_fini: - usnic_uiom_fini(); return err; } @@ -697,7 +696,6 @@ static void __exit usnic_ib_destroy(void) unregister_inetaddr_notifier(&usnic_ib_inetaddr_notifier); unregister_netdevice_notifier(&usnic_ib_netdevice_notifier); pci_unregister_driver(&usnic_ib_pci_driver); - usnic_uiom_fini(); } MODULE_DESCRIPTION("Cisco VIC (usNIC) Verbs Driver"); diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c index 854436a..06862a6a 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.c +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c @@ -47,8 +47,6 @@ #include "usnic_uiom.h" #include "usnic_uiom_interval_tree.h" -static struct workqueue_struct *usnic_uiom_wq; - #define USNIC_UIOM_PAGE_CHUNK \ ((PAGE_SIZE - offsetof(struct usnic_uiom_chunk, page_list)) /\ ((void *) &((struct usnic_uiom_chunk *) 0)->page_list[1] - \ @@ -127,9 +125,9 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, npages = PAGE_ALIGN(size + (addr & ~PAGE_MASK)) >> PAGE_SHIFT; uiomr->owning_mm = mm = current->mm; - down_write(&mm->mmap_sem); + down_read(&mm->mmap_sem); - locked = npages + atomic64_read(¤t->mm->pinned_vm); + locked = atomic64_add_return(npages, ¤t->mm->pinned_vm); lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { @@ -184,14 +182,13 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, } out: - if (ret < 0) + if (ret < 0) { usnic_uiom_put_pages(chunk_list, 0); - else { - atomic64_set(&mm->pinned_vm, locked); + atomic64_sub(npages, ¤t->mm->pinned_vm); + } else mmgrab(uiomr->owning_mm); - } - up_write(&mm->mmap_sem); + up_read(&mm->mmap_sem); free_page((unsigned long) page_list); return ret; } @@ -435,43 +432,12 @@ static inline size_t usnic_uiom_num_pages(struct usnic_uiom_reg *uiomr) return PAGE_ALIGN(uiomr->length + uiomr->offset) >> PAGE_SHIFT; } -static void usnic_uiom_release_defer(struct work_struct *work) -{ - struct usnic_uiom_reg *uiomr = - container_of(work, struct usnic_uiom_reg, work); - - down_write(&uiomr->owning_mm->mmap_sem); - atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm); - up_write(&uiomr->owning_mm->mmap_sem); - - __usnic_uiom_release_tail(uiomr); -} - void usnic_uiom_reg_release(struct usnic_uiom_reg *uiomr, struct ib_ucontext *context) { __usnic_uiom_reg_release(uiomr->pd, uiomr, 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 to a workqueue. - */ - if (context->closing) { - if (!down_write_trylock(&uiomr->owning_mm->mmap_sem)) { - INIT_WORK(&uiomr->work, usnic_uiom_release_defer); - queue_work(usnic_uiom_wq, &uiomr->work); - return; - } - } else { - down_write(&uiomr->owning_mm->mmap_sem); - } atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm); - up_write(&uiomr->owning_mm->mmap_sem); - __usnic_uiom_release_tail(uiomr); } @@ -600,17 +566,5 @@ int usnic_uiom_init(char *drv_name) return -EPERM; } - usnic_uiom_wq = create_workqueue(drv_name); - if (!usnic_uiom_wq) { - usnic_err("Unable to alloc wq for drv %s\n", drv_name); - return -ENOMEM; - } - return 0; } - -void usnic_uiom_fini(void) -{ - flush_workqueue(usnic_uiom_wq); - destroy_workqueue(usnic_uiom_wq); -} diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.h b/drivers/infiniband/hw/usnic/usnic_uiom.h index b86a973..c88cfa08 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.h +++ b/drivers/infiniband/hw/usnic/usnic_uiom.h @@ -93,5 +93,4 @@ struct usnic_uiom_reg *usnic_uiom_reg_get(struct usnic_uiom_pd *pd, void usnic_uiom_reg_release(struct usnic_uiom_reg *uiomr, struct ib_ucontext *ucontext); int usnic_uiom_init(char *drv_name); -void usnic_uiom_fini(void); #endif /* USNIC_UIOM_H_ */ -- 2.7.4