The patch titled
Subject: resource: add walk_system_ram_res_rev()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
resource-add-walk_system_ram_res_rev.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/resource-add-walk_system_ram_res_rev.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Baoquan He <bhe@xxxxxxxxxx>
Subject: resource: add walk_system_ram_res_rev()
Date: Wed, 15 Nov 2023 21:00:27 +0800
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 to load kernel, initrd etc when
preparing kexec reboot.
Link: https://lkml.kernel.org/r/ZVTA6z/06cLnWKUz@MiWiFi-R3L-srv
Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/ioport.h | 3 ++
kernel/resource.c | 57 +++++++++++++++++++++++++++++++++++++++
2 files changed, 60 insertions(+)
--- a/include/linux/ioport.h~resource-add-walk_system_ram_res_rev
+++ a/include/linux/ioport.h
@@ -331,6 +331,9 @@ 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 *));
--- a/kernel/resource.c~resource-add-walk_system_ram_res_rev
+++ a/kernel/resource.c
@@ -27,6 +27,8 @@
#include <linux/mount.h>
#include <linux/resource_ext.h>
#include <uapi/linux/magic.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
#include <asm/io.h>
@@ -430,6 +432,61 @@ int walk_system_ram_res(u64 start, u64 e
}
/*
+ * 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 *))
+{
+ struct resource res, *rams;
+ int rams_size = 16, i;
+ unsigned long flags;
+ int ret = -1;
+
+ /* create a list */
+ rams = kvcalloc(rams_size, sizeof(struct resource), GFP_KERNEL);
+ if (!rams)
+ return ret;
+
+ flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+ i = 0;
+ while ((start < end) &&
+ (!find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res))) {
+ if (i >= rams_size) {
+ /* re-alloc */
+ struct resource *rams_new;
+
+ rams_new = kvrealloc(rams, rams_size * sizeof(struct resource),
+ (rams_size + 16) * sizeof(struct resource),
+ GFP_KERNEL);
+ if (!rams_new)
+ goto out;
+
+ rams = rams_new;
+ rams_size += 16;
+ }
+
+ rams[i].start = res.start;
+ rams[i++].end = res.end;
+
+ start = res.end + 1;
+ }
+
+ /* go reverse */
+ for (i--; i >= 0; i--) {
+ ret = (*func)(&rams[i], arg);
+ if (ret)
+ break;
+ }
+
+out:
+ kvfree(rams);
+ return ret;
+}
+
+/*
* This function calls the @func callback against all memory ranges, which
* are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
*/
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx are
resource-add-walk_system_ram_res_rev.patch
kexec_file-load-kernel-at-top-of-system-ram-if-required.patch
