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Message-ID: <YFnMyJl7dAZLM6S3@smile.fi.intel.com>
Date: Tue, 23 Mar 2021 13:11:04 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: David Hildenbrand <david@...hat.com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Dan Williams <dan.j.williams@...el.com>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
Vivek Goyal <vgoyal@...hat.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Keith Busch <keith.busch@...el.com>,
Michal Hocko <mhocko@...e.com>, Qian Cai <cai@....pw>,
Oscar Salvador <osalvador@...e.de>,
Eric Biederman <ebiederm@...ssion.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>,
Tom Lendacky <thomas.lendacky@....com>,
Brijesh Singh <brijesh.singh@....com>, x86@...nel.org,
kexec@...ts.infradead.org
Subject: Re: [PATCH v1 3/3] kernel/resource: remove first_lvl / siblings_only
logic
On Mon, Mar 22, 2021 at 05:02:00PM +0100, David Hildenbrand wrote:
> All IORESOURCE_SYSTEM_RAM and IORESOURCE_MEM now properly consider the
> whole resource tree, not just the first level. Let's drop the unused
> first_lvl / siblings_only logic.
>
> All functions properly search the whole tree, so remove documentation
> that indicates that some functions behave differently.
Like this clean up!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Although a few nit-picks below.
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Daniel Vetter <daniel.vetter@...ll.ch>
> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Cc: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> Cc: Signed-off-by: David Hildenbrand <david@...hat.com>
> Cc: Dave Young <dyoung@...hat.com>
> Cc: Baoquan He <bhe@...hat.com>
> Cc: Vivek Goyal <vgoyal@...hat.com>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Keith Busch <keith.busch@...el.com>
> Cc: Michal Hocko <mhocko@...e.com>
> Cc: Qian Cai <cai@....pw>
> Cc: Oscar Salvador <osalvador@...e.de>
> Cc: Eric Biederman <ebiederm@...ssion.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: "H. Peter Anvin" <hpa@...or.com>
> Cc: Tom Lendacky <thomas.lendacky@....com>
> Cc: Brijesh Singh <brijesh.singh@....com>
> Cc: x86@...nel.org
> Cc: kexec@...ts.infradead.org
> Signed-off-by: David Hildenbrand <david@...hat.com>
> ---
> kernel/resource.c | 45 ++++++++++++---------------------------------
> 1 file changed, 12 insertions(+), 33 deletions(-)
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 16e0c7e8ed24..7e00239a023a 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -64,12 +64,8 @@ static DEFINE_RWLOCK(resource_lock);
> static struct resource *bootmem_resource_free;
> static DEFINE_SPINLOCK(bootmem_resource_lock);
>
> -static struct resource *next_resource(struct resource *p, bool sibling_only)
> +static struct resource *next_resource(struct resource *p)
> {
> - /* Caller wants to traverse through siblings only */
> - if (sibling_only)
> - return p->sibling;
> -
> if (p->child)
> return p->child;
> while (!p->sibling && p->parent)
> @@ -81,7 +77,7 @@ static void *r_next(struct seq_file *m, void *v, loff_t *pos)
> {
> struct resource *p = v;
> (*pos)++;
> - return (void *)next_resource(p, false);
> + return (void *)next_resource(p);
> }
>
> #ifdef CONFIG_PROC_FS
> @@ -330,14 +326,10 @@ EXPORT_SYMBOL(release_resource);
> * of the resource that's within [@start..@end]; if none is found, returns
> * -ENODEV. Returns -EINVAL for invalid parameters.
> *
> - * This function walks the whole tree and not just first level children
> - * unless @first_lvl is true.
> - *
> * @start: start address of the resource searched for
> * @end: end address of same resource
> * @flags: flags which the resource must have
> * @desc: descriptor the resource must have
> - * @first_lvl: walk only the first level children, if set
> * @res: return ptr, if resource found
> *
> * The caller must specify @start, @end, @flags, and @desc
> @@ -345,9 +337,8 @@ EXPORT_SYMBOL(release_resource);
> */
> static int find_next_iomem_res(resource_size_t start, resource_size_t end,
> unsigned long flags, unsigned long desc,
> - bool first_lvl, struct resource *res)
> + struct resource *res)
> {
> - bool siblings_only = true;
> struct resource *p;
>
> if (!res)
> @@ -358,7 +349,7 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
>
> read_lock(&resource_lock);
>
> - for (p = iomem_resource.child; p; p = next_resource(p, siblings_only)) {
> + for (p = iomem_resource.child; p; p = next_resource(p)) {
> /* If we passed the resource we are looking for, stop */
> if (p->start > end) {
> p = NULL;
> @@ -369,13 +360,6 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
> if (p->end < start)
> continue;
>
> - /*
> - * Now that we found a range that matches what we look for,
> - * check the flags and the descriptor. If we were not asked to
> - * use only the first level, start looking at children as well.
> - */
> - siblings_only = first_lvl;
> -
> if ((p->flags & flags) != flags)
> continue;
> if ((desc != IORES_DESC_NONE) && (desc != p->desc))
> @@ -402,14 +386,14 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
>
> static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
> unsigned long flags, unsigned long desc,
> - bool first_lvl, void *arg,
> + void *arg,
> int (*func)(struct resource *, void *))
Can it be one line?
> {
> struct resource res;
> int ret = -EINVAL;
>
> while (start < end &&
> - !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) {
> + !find_next_iomem_res(start, end, flags, desc, &res)) {
> ret = (*func)(&res, arg);
> if (ret)
> break;
> @@ -431,7 +415,6 @@ static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
> * @arg: function argument for the callback @func
> * @func: callback function that is called for each qualifying resource area
> *
> - * This walks through whole tree and not just first level children.
> * All the memory ranges which overlap start,end and also match flags and
> * desc are valid candidates.
> *
> @@ -441,7 +424,7 @@ static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
> int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
> u64 end, void *arg, int (*func)(struct resource *, void *))
> {
> - return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func);
> + return __walk_iomem_res_desc(start, end, flags, desc, arg, func);
> }
> EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
>
> @@ -457,8 +440,8 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
> {
> unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>
> - return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, false,
> - arg, func);
> + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
> + func);
I guess you may do it on one line.
> }
>
> /*
> @@ -470,17 +453,14 @@ int walk_mem_res(u64 start, u64 end, void *arg,
> {
> unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
>
> - return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, false,
> - arg, func);
> + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
> + func);
Ditto.
> }
>
> /*
> * This function calls the @func callback against all memory ranges of type
> * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
> * It is to be used only for System RAM.
> - *
> - * This will find System RAM ranges that are children of top-level resources
> - * in addition to top-level System RAM resources.
> */
> int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
> void *arg, int (*func)(unsigned long, unsigned long, void *))
> @@ -495,8 +475,7 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
> end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
> flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> while (start < end &&
> - !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
> - false, &res)) {
> + !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res)) {
> pfn = PFN_UP(res.start);
> end_pfn = PFN_DOWN(res.end + 1);
> if (end_pfn > pfn)
> --
> 2.29.2
>
--
With Best Regards,
Andy Shevchenko
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