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From: Baoquan He <bhe@redhat.com>
To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
	robh+dt@kernel.org, dan.j.williams@intel.com,
	nicolas.pitre@linaro.org, josh@joshtriplett.org
Cc: "Baoquan He" <bhe@redhat.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Brijesh Singh" <brijesh.singh@amd.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Borislav Petkov" <bp@suse.de>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Wei Yang" <richard.weiyang@gmail.com>
Subject: [PATCH v3 2/3] resource: add walk_system_ram_res_rev()
Date: Thu, 19 Apr 2018 08:18:47 +0800	[thread overview]
Message-ID: <20180419001848.3041-3-bhe@redhat.com> (raw)
In-Reply-To: <20180419001848.3041-1-bhe@redhat.com>

This function, being a variant of walk_system_ram_res() introduced in
commit 8c86e70acead ("resource: provide new functions to walk through
resources"), walks through a list of all the resources of System RAM
in reversed order, i.e., from higher to lower.

It will be used in kexec_file code.

Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
---
 include/linux/ioport.h |  3 +++
 kernel/resource.c      | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 225d13d3500a..5f2cfb460a14 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -278,6 +278,9 @@ extern int
 walk_system_ram_res(u64 start, u64 end, void *arg,
 		    int (*func)(struct resource *, void *));
 extern int
+walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+			int (*func)(struct resource *, void *));
+extern int
 walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
 		    void *arg, int (*func)(struct resource *, void *));
 
diff --git a/kernel/resource.c b/kernel/resource.c
index 4f560991c130..6c519b06e3d6 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -23,6 +23,8 @@
 #include <linux/pfn.h>
 #include <linux/mm.h>
 #include <linux/resource_ext.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
 #include <asm/io.h>
 
 
@@ -475,6 +477,44 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
 }
 
 /*
+ * This function, being a variant of walk_system_ram_res(), calls the @func
+ * callback against all memory ranges of type System RAM which are marked as
+ * IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY in reversed order, i.e., from
+ * higher to lower.
+ */
+int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+				int (*func)(struct resource *, void *))
+{
+	unsigned long flags;
+	struct resource *res;
+	int ret = -1;
+
+	flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+	read_lock(&resource_lock);
+	list_for_each_entry_reverse(res, &iomem_resource.child, sibling) {
+		if (start >= end)
+			break;
+		if ((res->flags & flags) != flags)
+			continue;
+		if (res->desc != IORES_DESC_NONE)
+			continue;
+		if (res->end < start)
+			break;
+
+		if ((res->end >= start) && (res->start < end)) {
+			ret = (*func)(res, arg);
+			if (ret)
+				break;
+		}
+		end = res->start - 1;
+
+	}
+	read_unlock(&resource_lock);
+	return ret;
+}
+
+/*
  * This function calls the @func callback against all memory ranges, which
  * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
  */
-- 
2.13.6

  parent reply	other threads:[~2018-04-19  0:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-19  0:18 [PATCH v3 0/3] resource: Use list_head to link sibling resource Baoquan He
2018-04-19  0:18 ` [PATCH v3 1/3] " Baoquan He
2018-04-26  1:18   ` Wei Yang
2018-05-07  1:14     ` Baoquan He
2018-05-08 11:48       ` Wei Yang
2018-05-08 12:11         ` Baoquan He
2018-05-08 23:41           ` Wei Yang
2018-04-26  3:01   ` kbuild test robot
2018-05-06  6:31     ` Baoquan He
2018-04-26  3:23   ` kbuild test robot
2018-05-06  6:30     ` Baoquan He
2018-04-19  0:18 ` Baoquan He [this message]
2018-04-19 10:07   ` [PATCH v3 2/3] resource: add walk_system_ram_res_rev() Borislav Petkov
2018-04-26  8:56     ` Baoquan He
2018-04-26 11:09       ` Borislav Petkov
2018-04-26 13:22         ` Baoquan He
2018-05-04 10:16           ` Borislav Petkov
2018-05-06  6:19             ` Baoquan He
2018-04-19  0:18 ` [PATCH v3 3/3] kexec_file: Load kernel at top of system RAM if required Baoquan He

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