From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id EEE8A8E0006 for ; Tue, 15 Jan 2019 13:13:31 -0500 (EST) Received: by mail-pf1-f200.google.com with SMTP id q64so2531173pfa.18 for ; Tue, 15 Jan 2019 10:13:31 -0800 (PST) Received: from smtp2.provo.novell.com (smtp2.provo.novell.com. [137.65.250.81]) by mx.google.com with ESMTPS id v75si3889866pfd.157.2019.01.15.10.13.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 15 Jan 2019 10:13:30 -0800 (PST) From: Davidlohr Bueso Subject: [PATCH 4/6] drivers/IB,hfi1: do not se mmap_sem Date: Tue, 15 Jan 2019 10:12:58 -0800 Message-Id: <20190115181300.27547-5-dave@stgolabs.net> In-Reply-To: <20190115181300.27547-1-dave@stgolabs.net> References: <20190115181300.27547-1-dave@stgolabs.net> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: dledford@redhat.com, jgg@mellanox.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, dave@stgolabs.net, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, Davidlohr Bueso This driver already uses gup_fast() and thus we can just drop the mmap_sem protection around the pinned_vm counter. Note that the window between when hfi1_can_pin_pages() is called and the actual counter is incremented remains the same as mmap_sem was _only_ used for when ->pinned_vm was touched. Cc: mike.marciniszyn@intel.com Cc: dennis.dalessandro@intel.com Signed-off-by: Davidlohr Bueso --- drivers/infiniband/hw/hfi1/user_pages.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c index df86a596d746..f0c6f219f575 100644 --- a/drivers/infiniband/hw/hfi1/user_pages.c +++ b/drivers/infiniband/hw/hfi1/user_pages.c @@ -91,9 +91,7 @@ bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm, /* Convert to number of pages */ size = DIV_ROUND_UP(size, PAGE_SIZE); - down_read(&mm->mmap_sem); pinned = atomic_long_read(&mm->pinned_vm); - up_read(&mm->mmap_sem); /* First, check the absolute limit against all pinned pages. */ if (pinned + npages >= ulimit && !can_lock) @@ -111,9 +109,7 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np if (ret < 0) return ret; - down_write(&mm->mmap_sem); atomic_long_add(ret, &mm->pinned_vm); - up_write(&mm->mmap_sem); return ret; } @@ -130,8 +126,6 @@ void hfi1_release_user_pages(struct mm_struct *mm, struct page **p, } if (mm) { /* during close after signal, mm can be NULL */ - down_write(&mm->mmap_sem); atomic_long_sub(npages, &mm->pinned_vm); - up_write(&mm->mmap_sem); } } -- 2.16.4