From 5c1edea773c98707fbb23d1df168bcff52f61e4b Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 25 Sep 2024 18:43:34 +0300 Subject: resource: replace open coded resource_intersection() Patch series "resource: A couple of cleanups". A couple of ad-hoc cleanups since there was a recent development of the code in question. No functional changes intended. This patch (of 2): __region_intersects() uses open coded resource_intersection(). Replace it with existing API which also make more clear what we are checking. Link: https://lkml.kernel.org/r/20240925154355.1170859-1-andriy.shevchenko@linux.intel.com Link: https://lkml.kernel.org/r/20240925154355.1170859-2-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Rasmus Villemoes Signed-off-by: Andrew Morton --- kernel/resource.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'kernel/resource.c') diff --git a/kernel/resource.c b/kernel/resource.c index 4101016e8b20..1c77ac239c7a 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -537,17 +537,16 @@ static int __region_intersects(struct resource *parent, resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { - resource_size_t ostart, oend; int type = 0; int other = 0; struct resource *p, *dp; + struct resource res, o; bool is_type, covered; - struct resource res; res.start = start; res.end = start + size - 1; for (p = parent->child; p ; p = p->sibling) { - if (!resource_overlaps(p, &res)) + if (!resource_intersection(p, &res, &o)) continue; is_type = (p->flags & flags) == flags && (desc == IORES_DESC_NONE || desc == p->desc); @@ -568,8 +567,6 @@ static int __region_intersects(struct resource *parent, resource_size_t start, * |-- "System RAM" --||-- "CXL Window 0a" --| */ covered = false; - ostart = max(res.start, p->start); - oend = min(res.end, p->end); for_each_resource(p, dp, false) { if (!resource_overlaps(dp, &res)) continue; @@ -578,17 +575,17 @@ static int __region_intersects(struct resource *parent, resource_size_t start, if (is_type) { type++; /* - * Range from 'ostart' to 'dp->start' + * Range from 'o.start' to 'dp->start' * isn't covered by matched resource. */ - if (dp->start > ostart) + if (dp->start > o.start) break; - if (dp->end >= oend) { + if (dp->end >= o.end) { covered = true; break; } /* Remove covered range */ - ostart = max(ostart, dp->end + 1); + o.start = max(o.start, dp->end + 1); } } if (!covered) -- cgit v1.2.3 From ba1eccc114ffc62c4495a5e15659190fa2c42308 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 25 Sep 2024 18:43:35 +0300 Subject: resource: introduce is_type_match() helper and use it There are already a couple of places where we may replace a few lines of code by calling a helper, which increases readability while deduplicating the code. Introduce is_type_match() helper and use it. Link: https://lkml.kernel.org/r/20240925154355.1170859-3-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Rasmus Villemoes Signed-off-by: Andrew Morton --- kernel/resource.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) (limited to 'kernel/resource.c') diff --git a/kernel/resource.c b/kernel/resource.c index 1c77ac239c7a..55bc09f50e21 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -297,6 +297,11 @@ int release_resource(struct resource *old) EXPORT_SYMBOL(release_resource); +static bool is_type_match(struct resource *p, unsigned long flags, unsigned long desc) +{ + return (p->flags & flags) == flags && (desc == IORES_DESC_NONE || desc == p->desc); +} + /** * find_next_iomem_res - Finds the lowest iomem resource that covers part of * [@start..@end]. @@ -339,13 +344,9 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end, if (p->end < start) continue; - if ((p->flags & flags) != flags) - continue; - if ((desc != IORES_DESC_NONE) && (desc != p->desc)) - continue; - /* Found a match, break */ - break; + if (is_type_match(p, flags, desc)) + break; } if (p) { @@ -540,7 +541,7 @@ static int __region_intersects(struct resource *parent, resource_size_t start, int type = 0; int other = 0; struct resource *p, *dp; struct resource res, o; - bool is_type, covered; + bool covered; res.start = start; res.end = start + size - 1; @@ -548,9 +549,7 @@ static int __region_intersects(struct resource *parent, resource_size_t start, for (p = parent->child; p ; p = p->sibling) { if (!resource_intersection(p, &res, &o)) continue; - is_type = (p->flags & flags) == flags && - (desc == IORES_DESC_NONE || desc == p->desc); - if (is_type) { + if (is_type_match(p, flags, desc)) { type++; continue; } @@ -570,9 +569,7 @@ static int __region_intersects(struct resource *parent, resource_size_t start, for_each_resource(p, dp, false) { if (!resource_overlaps(dp, &res)) continue; - is_type = (dp->flags & flags) == flags && - (desc == IORES_DESC_NONE || desc == dp->desc); - if (is_type) { + if (is_type_match(dp, flags, desc)) { type++; /* * Range from 'o.start' to 'dp->start' -- cgit v1.2.3 From 834b251b1db6b88b9364955196e5e32746e5ccc7 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Wed, 9 Oct 2024 15:57:51 +0300 Subject: resource: correct reallocate_resource() documentation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit reallocate_resource() documentation claims constraint is about "the size and alignment" but the size is provided in another parameter. Instead of size, constraint has the allowed memory range (min, max) so change the wording to reflect that. Link: https://lkml.kernel.org/r/20241009125751.8090-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Andrew Morton --- kernel/resource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/resource.c') diff --git a/kernel/resource.c b/kernel/resource.c index 55bc09f50e21..2d4208b2f62f 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -738,7 +738,7 @@ EXPORT_SYMBOL_GPL(find_resource_space); * @root: root resource descriptor * @old: resource descriptor desired by caller * @newsize: new size of the resource descriptor - * @constraint: the size and alignment constraints to be met. + * @constraint: the memory range and alignment constraints to be met. */ static int reallocate_resource(struct resource *root, struct resource *old, resource_size_t newsize, -- cgit v1.2.3 From d7ce9c73da54a096311edbf4688b78b179dd79bc Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Tue, 29 Oct 2024 20:27:35 +0800 Subject: resource: avoid unnecessary resource tree walking in __region_intersects() Currently, if __region_intersects() finds any overlapped but unmatched resource, it walks the descendant resource tree to check for overlapped and matched descendant resources using for_each_resource(). However, in current kernel, for_each_resource() iterates not only the descendant tree, but also subsequent sibling trees in certain scenarios. While this doesn't introduce bugs, it makes code hard to be understood and potentially inefficient. So, the patch revises next_resource() and for_each_resource() and makes for_each_resource() traverse the subtree under the specified subtree root only. Test shows that this avoids unnecessary resource tree walking in __region_intersects(). For the example resource tree as follows, X | A----D----E | B--C if 'A' is the overlapped but unmatched resource, original kernel iterates 'B', 'C', 'D', 'E' when it walks the descendant tree. While the patched kernel iterates only 'B', 'C'. Thanks David Hildenbrand for providing a good resource tree example. Link: https://lkml.kernel.org/r/20241029122735.79164-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" Acked-by: Dan Williams Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Jonathan Cameron Cc: Alistair Popple Cc: Andy Shevchenko Cc: Bjorn Helgaas Cc: Baoquan He Cc: Dave Jiang Cc: Alison Schofield Signed-off-by: Andrew Morton --- kernel/resource.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) (limited to 'kernel/resource.c') diff --git a/kernel/resource.c b/kernel/resource.c index 2d4208b2f62f..59c6e608f1d1 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -50,17 +50,35 @@ EXPORT_SYMBOL(iomem_resource); static DEFINE_RWLOCK(resource_lock); -static struct resource *next_resource(struct resource *p, bool skip_children) +/* + * Return the next node of @p in pre-order tree traversal. If + * @skip_children is true, skip the descendant nodes of @p in + * traversal. If @p is a descendant of @subtree_root, only traverse + * the subtree under @subtree_root. + */ +static struct resource *next_resource(struct resource *p, bool skip_children, + struct resource *subtree_root) { if (!skip_children && p->child) return p->child; - while (!p->sibling && p->parent) + while (!p->sibling && p->parent) { p = p->parent; + if (p == subtree_root) + return NULL; + } return p->sibling; } +/* + * Traverse the resource subtree under @_root in pre-order, excluding + * @_root itself. + * + * NOTE: '__p' is introduced to avoid shadowing '_p' outside of loop. + * And it is referenced to avoid unused variable warning. + */ #define for_each_resource(_root, _p, _skip_children) \ - for ((_p) = (_root)->child; (_p); (_p) = next_resource(_p, _skip_children)) + for (typeof(_root) __root = (_root), __p = _p = __root->child; \ + __p && _p; _p = next_resource(_p, _skip_children, __root)) #ifdef CONFIG_PROC_FS @@ -88,7 +106,7 @@ static void *r_next(struct seq_file *m, void *v, loff_t *pos) (*pos)++; - return (void *)next_resource(p, false); + return (void *)next_resource(p, false, NULL); } static void r_stop(struct seq_file *m, void *v) -- cgit v1.2.3