On Wednesday, August 11, 2021, David Hildenbrand <david@xxxxxxxxxx> wrote:
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@xxxxxxxxxx>
---
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 ;) {
I consider the ordinal part of p initialization is slightly better and done outside of read lock.
Something like
p= &iomem_res...;
read lock
for (p = p->child; ...) {
/*
* 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
--
With Best Regards,
Andy Shevchenko
