All of lore.kernel.org
 help / color / mirror / Atom feed
From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Hanjun Guo <guohanjun@huawei.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	virtualization@lists.linux-foundation.org, linux-mm@kvack.org
Subject: [PATCH v1 3/3] kernel/resource: cleanup and optimize iomem_is_exclusive()
Date: Wed, 11 Aug 2021 22:36:12 +0200	[thread overview]
Message-ID: <20210811203612.138506-4-david@redhat.com> (raw)
In-Reply-To: <20210811203612.138506-1-david@redhat.com>

Let's clean it up a bit, removing the unnecessary usage of r_next() by
next_resource(), and use next_range_resource() in case we are not
interested in a certain subtree.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 kernel/resource.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 2938cf520ca3..ea853a075a83 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1754,9 +1754,8 @@ static int strict_iomem_checks;
  */
 bool iomem_is_exclusive(u64 addr)
 {
-	struct resource *p = &iomem_resource;
+	struct resource *p;
 	bool err = false;
-	loff_t l;
 	int size = PAGE_SIZE;
 
 	if (!strict_iomem_checks)
@@ -1765,27 +1764,31 @@ bool iomem_is_exclusive(u64 addr)
 	addr = addr & PAGE_MASK;
 
 	read_lock(&resource_lock);
-	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
+	for (p = iomem_resource.child; p ;) {
 		/*
 		 * We can probably skip the resources without
 		 * IORESOURCE_IO attribute?
 		 */
 		if (p->start >= addr + size)
 			break;
-		if (p->end < addr)
+		if (p->end < addr) {
+			/* No need to consider children */
+			p = next_resource_skip_children(p);
 			continue;
+		}
+
 		/*
 		 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
 		 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
 		 * resource is busy.
 		 */
-		if ((p->flags & IORESOURCE_BUSY) == 0)
-			continue;
-		if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
-				|| p->flags & IORESOURCE_EXCLUSIVE) {
+		if (p->flags & IORESOURCE_BUSY &&
+		    (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM) ||
+		     p->flags & IORESOURCE_EXCLUSIVE)) {
 			err = true;
 			break;
 		}
+		p = next_resource(p);
 	}
 	read_unlock(&resource_lock);
 
-- 
2.31.1


WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	virtualization@lists.linux-foundation.org, linux-mm@kvack.org,
	Hanjun Guo <guohanjun@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>
Subject: [PATCH v1 3/3] kernel/resource: cleanup and optimize iomem_is_exclusive()
Date: Wed, 11 Aug 2021 22:36:12 +0200	[thread overview]
Message-ID: <20210811203612.138506-4-david@redhat.com> (raw)
In-Reply-To: <20210811203612.138506-1-david@redhat.com>

Let's clean it up a bit, removing the unnecessary usage of r_next() by
next_resource(), and use next_range_resource() in case we are not
interested in a certain subtree.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 kernel/resource.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 2938cf520ca3..ea853a075a83 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1754,9 +1754,8 @@ static int strict_iomem_checks;
  */
 bool iomem_is_exclusive(u64 addr)
 {
-	struct resource *p = &iomem_resource;
+	struct resource *p;
 	bool err = false;
-	loff_t l;
 	int size = PAGE_SIZE;
 
 	if (!strict_iomem_checks)
@@ -1765,27 +1764,31 @@ bool iomem_is_exclusive(u64 addr)
 	addr = addr & PAGE_MASK;
 
 	read_lock(&resource_lock);
-	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
+	for (p = iomem_resource.child; p ;) {
 		/*
 		 * We can probably skip the resources without
 		 * IORESOURCE_IO attribute?
 		 */
 		if (p->start >= addr + size)
 			break;
-		if (p->end < addr)
+		if (p->end < addr) {
+			/* No need to consider children */
+			p = next_resource_skip_children(p);
 			continue;
+		}
+
 		/*
 		 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
 		 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
 		 * resource is busy.
 		 */
-		if ((p->flags & IORESOURCE_BUSY) == 0)
-			continue;
-		if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
-				|| p->flags & IORESOURCE_EXCLUSIVE) {
+		if (p->flags & IORESOURCE_BUSY &&
+		    (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM) ||
+		     p->flags & IORESOURCE_EXCLUSIVE)) {
 			err = true;
 			break;
 		}
+		p = next_resource(p);
 	}
 	read_unlock(&resource_lock);
 
-- 
2.31.1

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

  parent reply	other threads:[~2021-08-11 20:36 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 20:36 [PATCH v1 0/3] virtio-mem: disallow mapping virtio-mem memory via /dev/mem David Hildenbrand
2021-08-11 20:36 ` David Hildenbrand
2021-08-11 20:36 ` [PATCH v1 1/3] /dev/mem: disallow access to explicitly excluded system RAM regions David Hildenbrand
2021-08-11 20:36   ` David Hildenbrand
2021-08-11 20:50   ` Andy Shevchenko
2021-08-11 20:50     ` Andy Shevchenko
2021-08-11 20:36 ` [PATCH v1 2/3] virtio-mem: disallow mapping virtio-mem memory via /dev/mem David Hildenbrand
2021-08-11 20:36   ` David Hildenbrand
2021-08-11 20:36 ` David Hildenbrand [this message]
2021-08-11 20:36   ` [PATCH v1 3/3] kernel/resource: cleanup and optimize iomem_is_exclusive() David Hildenbrand
2021-08-11 20:47   ` Andy Shevchenko
2021-08-11 20:47     ` Andy Shevchenko
2021-08-12  7:07     ` David Hildenbrand
2021-08-12  7:07       ` David Hildenbrand
2021-08-12  7:07       ` David Hildenbrand
2021-08-12  7:14       ` Andy Shevchenko
2021-08-12  7:14         ` Andy Shevchenko
2021-08-12  7:34         ` David Hildenbrand
2021-08-12  7:34           ` David Hildenbrand
2021-08-12  7:34           ` David Hildenbrand
2021-08-12 11:15           ` Andy Shevchenko
2021-08-12 11:15             ` Andy Shevchenko
2021-08-12 11:15             ` Andy Shevchenko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210811203612.138506-4-david@redhat.com \
    --to=david@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=arnd@arndb.de \
    --cc=dan.j.williams@intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=guohanjun@huawei.com \
    --cc=jasowang@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mst@redhat.com \
    --cc=rafael.j.wysocki@intel.com \
    --cc=virtualization@lists.linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.