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[PATCH v6 42/53] resources: Split out __allocate_resource()

From Yinghai Lu <yinghai@kernel.org>
Newsgroups linux.kernel
Subject [PATCH v6 42/53] resources: Split out __allocate_resource()
Date 2015-10-01 08:10 +0200
Message-ID <qeFe3-3CQ-35@gated-at.bofh.it> (permalink)
References <qeF4l-3bG-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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This one is separated from next patch for best fit allocation.

Split out __allocate_resource(), and it will not hold lock, so we could use it
in other functions that hold the resource lock already.

-v2: according to Linus, using "bool lock" as parameter
     aka "conditionally take lock" is *wrong*.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/resource.c | 70 +++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 50 insertions(+), 20 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 6927298..62321b0 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -654,7 +654,7 @@ static int find_resource(struct resource *root, struct resource *new,
 }
 
 /**
- * reallocate_resource - allocate a slot in the resource tree given range & alignment.
+ * __reallocate_resource - allocate a slot in the resource tree given range & alignment.
  *	The resource will be relocated if the new size cannot be reallocated in the
  *	current location.
  *
@@ -663,7 +663,7 @@ static int find_resource(struct resource *root, struct resource *new,
  * @newsize: new size of the resource descriptor
  * @constraint: the size and alignment constraints to be met.
  */
-static int reallocate_resource(struct resource *root, struct resource *old,
+static int __reallocate_resource(struct resource *root, struct resource *old,
 			resource_size_t newsize,
 			struct resource_constraint  *constraint)
 {
@@ -671,8 +671,6 @@ static int reallocate_resource(struct resource *root, struct resource *old,
 	struct resource new = *old;
 	struct resource *conflict;
 
-	write_lock(&resource_lock);
-
 	if ((err = __find_resource(root, old, &new, newsize, constraint)))
 		goto out;
 
@@ -697,14 +695,13 @@ static int reallocate_resource(struct resource *root, struct resource *old,
 		BUG_ON(conflict);
 	}
 out:
-	write_unlock(&resource_lock);
 	return err;
 }
 
-
 /**
- * allocate_resource - allocate empty slot in the resource tree given range & alignment.
- * 	The resource will be reallocated with a new size if it was already allocated
+ * __allocate_resource - allocate empty slot in the resource tree given range & alignment.
+ *	The resource will be reallocated with a new size if it was already
+ *	allocated
  * @root: root resource descriptor
  * @new: resource descriptor desired by caller
  * @size: requested resource region size
@@ -713,15 +710,17 @@ out:
  * @align: alignment requested, in bytes
  * @alignf: alignment function, optional, called if not NULL
  * @alignf_data: arbitrary data to pass to the @alignf function
+ *
+ * Caller need to hold resource_lock if needed.
  */
-int allocate_resource(struct resource *root, struct resource *new,
-		      resource_size_t size, resource_size_t min,
-		      resource_size_t max, resource_size_t align,
-		      resource_size_t (*alignf)(void *,
-						const struct resource *,
-						resource_size_t,
-						resource_size_t),
-		      void *alignf_data)
+static int __allocate_resource(struct resource *root, struct resource *new,
+				resource_size_t size, resource_size_t min,
+				resource_size_t max, resource_size_t align,
+				resource_size_t (*alignf)(void *,
+						  const struct resource *,
+						  resource_size_t,
+						  resource_size_t),
+				void *alignf_data)
 {
 	int err;
 	struct resource_constraint constraint;
@@ -735,20 +734,51 @@ int allocate_resource(struct resource *root, struct resource *new,
 	constraint.alignf = alignf;
 	constraint.alignf_data = alignf_data;
 
-	if ( new->parent ) {
+	if (new->parent) {
 		/* resource is already allocated, try reallocating with
 		   the new constraints */
-		return reallocate_resource(root, new, size, &constraint);
+		return __reallocate_resource(root, new, size, &constraint);
 	}
 
-	write_lock(&resource_lock);
 	err = find_resource(root, new, size, &constraint);
 	if (err >= 0 && __request_resource(root, new))
 		err = -EBUSY;
-	write_unlock(&resource_lock);
+
 	return err;
 }
 
+/**
+ * allocate_resource - allocate empty slot in the resource tree given range & alignment.
+ *	The resource will be reallocated with a new size if it was already
+ *	allocated
+ * @root: root resource descriptor
+ * @new: resource descriptor desired by caller
+ * @size: requested resource region size
+ * @min: minimum boundary to allocate
+ * @max: maximum boundary to allocate
+ * @align: alignment requested, in bytes
+ * @alignf: alignment function, optional, called if not NULL
+ * @alignf_data: arbitrary data to pass to the @alignf function
+ */
+int allocate_resource(struct resource *root, struct resource *new,
+		      resource_size_t size, resource_size_t min,
+		      resource_size_t max, resource_size_t align,
+		      resource_size_t (*alignf)(void *,
+						const struct resource *,
+						resource_size_t,
+						resource_size_t),
+		      void *alignf_data)
+{
+	int ret;
+
+	write_lock(&resource_lock);
+	ret = __allocate_resource(root, new, size, min, max, align,
+				   alignf, alignf_data);
+	write_unlock(&resource_lock);
+
+	return ret;
+}
+
 EXPORT_SYMBOL(allocate_resource);
 
 /**
-- 
1.8.4.5

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Thread

[PATCH v6 00/53] PCI: Resource allocation cleanup for v4.4 Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 27/53] PCI: Separate out save_resources()/restore_resources() Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 41/53] PCI: Kill macro checking for bus io port sizing Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 38/53] PCI: Unify calculate_size() for io port and MMIO Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 46/53] PCI: Check pref compatible bit for mem64 resource of PCIe device Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 35/53] PCI: Don't add too much optional size for hotplug bridge io Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 50/53] PCI: Restore pref MMIO allocation logic for host bridge without mmio64 Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 16/53] PCI: Optimize bus align/size calculation for optional during sizing Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 21/53] PCI: Treat ROM resource as optional during realloc Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 30/53] PCI: Skip required+optional if there is no optional Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 39/53] PCI: Allow bridge optional only io port resource required size to be 0 Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 25/53] PCI: Cache window alignment value during bus sizing Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 53/53] PCI: Don't set flags to 0 when assign resource fail Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 17/53] PCI: Don't add too much optional size for hotplug bridge MMIO Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 42/53] resources: Split out __allocate_resource() Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 48/53] PCI: Add has_mem64 for struct host_bridge Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 33/53] PCI: Add support for more than two alt_size entries under same bridge Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 45/53] PCI: Add debug print out for min_align and alt_size Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:10 +0200
  [PATCH v6 24/53] PCI: Add __add_to_list() Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:20 +0200
  [PATCH v6 44/53] PCI, x86: Allocate from high in available window for MMIO Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:20 +0200
  [PATCH v6 12/53] PCI: Cleanup res_to_dev_res() printout Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:20 +0200
  [PATCH v6 52/53] PCI: Introduce resource_disabled() Yinghai Lu <yinghai@kernel.org> - 2015-10-01 08:20 +0200
  [PATCH v6 51/53] PCI, x86: Add pci=assign_pref_bars to reallocate pref BARs Yinghai Lu <yinghai@kernel.org> - 2015-10-01 09:00 +0200
  [PATCH v6 26/53] PCI: Check if resource is allocated before trying to assign one Yinghai Lu <yinghai@kernel.org> - 2015-10-01 09:00 +0200
  [PATCH v6 20/53] PCI: Rename pdev_sort_resources() to pdev_assign_resources_prepare() Yinghai Lu <yinghai@kernel.org> - 2015-10-01 09:00 +0200
  [PATCH v6 49/53] PCI: Only treat non-pref mmio64 as pref if host bridge has mmio64 Yinghai Lu <yinghai@kernel.org> - 2015-10-01 09:00 +0200
  [PATCH v6 34/53] PCI: Fix size calculation with old_size on rescan path Yinghai Lu <yinghai@kernel.org> - 2015-10-01 09:00 +0200

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