From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754512AbeARAHM (ORCPT ); Wed, 17 Jan 2018 19:07:12 -0500 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:14929 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752062AbeARAHL (ORCPT ); Wed, 17 Jan 2018 19:07:11 -0500 X-IronPort-AV: E=Sophos;i="5.46,374,1511827200"; d="scan'208";a="587415159" From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= To: Andrew Morton , Dan Williams Cc: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] mm: Fix devm_memremap_pages() collision handling Date: Thu, 18 Jan 2018 01:06:02 +0100 Message-Id: <20180118000602.5527-2-jschoenh@amazon.de> X-Mailer: git-send-email 2.9.3.1.gcba166c.dirty In-Reply-To: <20180118000602.5527-1-jschoenh@amazon.de> References: <20180118000602.5527-1-jschoenh@amazon.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If devm_memremap_pages() detects a collision while adding entries to the radix-tree, we call pgmap_radix_release(). Unfortunately, the function removes *all* entries for the range -- including the entries that caused the collision in the first place. Modify pgmap_radix_release() to take an additional argument to indicate where to stop, so that only newly added entries are removed from the tree. Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()") Signed-off-by: Jan H. Schönherr --- kernel/memremap.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/kernel/memremap.c b/kernel/memremap.c index 4712ce6..2b136d4 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -248,13 +248,16 @@ int device_private_entry_fault(struct vm_area_struct *vma, EXPORT_SYMBOL(device_private_entry_fault); #endif /* CONFIG_DEVICE_PRIVATE */ -static void pgmap_radix_release(struct resource *res) +static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff) { unsigned long pgoff, order; mutex_lock(&pgmap_lock); - foreach_order_pgoff(res, order, pgoff) + foreach_order_pgoff(res, order, pgoff) { + if (pgoff >= end_pgoff) + break; radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff); + } mutex_unlock(&pgmap_lock); synchronize_rcu(); @@ -309,7 +312,7 @@ static void devm_memremap_pages_release(struct device *dev, void *data) mem_hotplug_done(); untrack_pfn(NULL, PHYS_PFN(align_start), align_size); - pgmap_radix_release(res); + pgmap_radix_release(res, -1); dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc, "%s: failed to free all reserved pages\n", __func__); } @@ -459,7 +462,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, untrack_pfn(NULL, PHYS_PFN(align_start), align_size); err_pfn_remap: err_radix: - pgmap_radix_release(res); + pgmap_radix_release(res, pgoff); devres_free(page_map); return ERR_PTR(error); } -- 2.9.3.1.gcba166c.dirty