| Message ID | 20170824081811.19299-4-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 24 August 2017 at 09:18, AKASHI Takahiro <takahiro.akashi@linaro.org> wrote: > 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 implementation on arm64. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > Cc: Vivek Goyal <vgoyal@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > --- > include/linux/ioport.h | 3 +++ > kernel/resource.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 51 insertions(+) > > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > index 6230064d7f95..9a212266299f 100644 > --- a/include/linux/ioport.h > +++ b/include/linux/ioport.h > @@ -271,6 +271,9 @@ extern int > walk_system_ram_res(u64 start, u64 end, void *arg, > int (*func)(u64, u64, void *)); > extern int > +walk_system_ram_res_rev(u64 start, u64 end, void *arg, > + int (*func)(u64, u64, void *)); > +extern int > walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, > void *arg, int (*func)(u64, u64, void *)); > > diff --git a/kernel/resource.c b/kernel/resource.c > index 9b5f04404152..1d6d734c75ac 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -23,6 +23,7 @@ > #include <linux/pfn.h> > #include <linux/mm.h> > #include <linux/resource_ext.h> > +#include <linux/vmalloc.h> > #include <asm/io.h> > > > @@ -469,6 +470,53 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, > return ret; > } > > +int walk_system_ram_res_rev(u64 start, u64 end, void *arg, > + int (*func)(u64, u64, void *)) > +{ > + struct resource res, *rams; > + u64 orig_end; > + int count, i; > + int ret = -1; > + > + count = 16; /* initial */ > +again: > + /* create a list */ > + rams = vmalloc(sizeof(struct resource) * count); > + if (!rams) > + return ret; > + > + res.start = start; > + res.end = end; > + res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > + orig_end = res.end; > + i = 0; > + while ((res.start < res.end) && > + (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { > + if (i >= count) { > + /* unlikely but */ > + vfree(rams); > + count += 16; If the count is likely to be < 16, why are we using vmalloc() here? > + goto again; > + } > + > + rams[i].start = res.start; > + rams[i++].end = res.end; > + > + res.start = res.end + 1; > + res.end = orig_end; > + } > + > + /* go reverse */ > + for (i--; i >= 0; i--) { > + ret = (*func)(rams[i].start, rams[i].end, arg); > + if (ret) > + break; > + } > + > + vfree(rams); > + return ret; > +} > + > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* > -- > 2.14.1 >
On Thu, Aug 24, 2017 at 10:06:28AM +0100, Ard Biesheuvel wrote: > On 24 August 2017 at 09:18, AKASHI Takahiro <takahiro.akashi@linaro.org> wrote: > > + /* create a list */ > > + rams = vmalloc(sizeof(struct resource) * count); > > + if (!rams) > > + return ret; > > + > > + res.start = start; > > + res.end = end; > > + res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > + orig_end = res.end; > > + i = 0; > > + while ((res.start < res.end) && > > + (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { > > + if (i >= count) { > > + /* unlikely but */ > > + vfree(rams); > > + count += 16; > > If the count is likely to be < 16, why are we using vmalloc() here? Ah, you're right :) -Takahiro AKASHI
On Thursday 24 August 2017 01:48 PM, AKASHI Takahiro wrote: > 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 implementation on arm64. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > Cc: Vivek Goyal <vgoyal@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > --- > include/linux/ioport.h | 3 +++ > kernel/resource.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 51 insertions(+) > > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > index 6230064d7f95..9a212266299f 100644 > --- a/include/linux/ioport.h > +++ b/include/linux/ioport.h > @@ -271,6 +271,9 @@ extern int > walk_system_ram_res(u64 start, u64 end, void *arg, > int (*func)(u64, u64, void *)); > extern int > +walk_system_ram_res_rev(u64 start, u64 end, void *arg, > + int (*func)(u64, u64, void *)); > +extern int > walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, > void *arg, int (*func)(u64, u64, void *)); > > diff --git a/kernel/resource.c b/kernel/resource.c > index 9b5f04404152..1d6d734c75ac 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -23,6 +23,7 @@ > #include <linux/pfn.h> > #include <linux/mm.h> > #include <linux/resource_ext.h> > +#include <linux/vmalloc.h> > #include <asm/io.h> > > > @@ -469,6 +470,53 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, > return ret; > } > > +int walk_system_ram_res_rev(u64 start, u64 end, void *arg, > + int (*func)(u64, u64, void *)) > +{ > + struct resource res, *rams; > + u64 orig_end; > + int count, i; > + int ret = -1; > + > + count = 16; /* initial */ > +again: > + /* create a list */ > + rams = vmalloc(sizeof(struct resource) * count); > + if (!rams) > + return ret; > + > + res.start = start; > + res.end = end; > + res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > + orig_end = res.end; > + i = 0; > + while ((res.start < res.end) && > + (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { > + if (i >= count) { > + /* unlikely but */ > + vfree(rams); > + count += 16; > + goto again; Wounld't it be better to re-alloc a bigger space,copy previous values and free the previous pointer, instead of going *again*. > + } > + > + rams[i].start = res.start; > + rams[i++].end = res.end; > + > + res.start = res.end + 1; > + res.end = orig_end; > + } > + > + /* go reverse */ > + for (i--; i >= 0; i--) { > + ret = (*func)(rams[i].start, rams[i].end, arg); > + if (ret) > + break; > + } > + > + vfree(rams); > + return ret; > +} > + > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* >
On Thu, Aug 31, 2017 at 08:04:51AM +0530, Pratyush Anand wrote: > > > On Thursday 24 August 2017 01:48 PM, AKASHI Takahiro wrote: > >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 implementation on arm64. > > > >Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > >Cc: Vivek Goyal <vgoyal@redhat.com> > >Cc: Andrew Morton <akpm@linux-foundation.org> > >Cc: Linus Torvalds <torvalds@linux-foundation.org> > >--- > > include/linux/ioport.h | 3 +++ > > kernel/resource.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 51 insertions(+) > > > >diff --git a/include/linux/ioport.h b/include/linux/ioport.h > >index 6230064d7f95..9a212266299f 100644 > >--- a/include/linux/ioport.h > >+++ b/include/linux/ioport.h > >@@ -271,6 +271,9 @@ extern int > > walk_system_ram_res(u64 start, u64 end, void *arg, > > int (*func)(u64, u64, void *)); > > extern int > >+walk_system_ram_res_rev(u64 start, u64 end, void *arg, > >+ int (*func)(u64, u64, void *)); > >+extern int > > walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, > > void *arg, int (*func)(u64, u64, void *)); > >diff --git a/kernel/resource.c b/kernel/resource.c > >index 9b5f04404152..1d6d734c75ac 100644 > >--- a/kernel/resource.c > >+++ b/kernel/resource.c > >@@ -23,6 +23,7 @@ > > #include <linux/pfn.h> > > #include <linux/mm.h> > > #include <linux/resource_ext.h> > >+#include <linux/vmalloc.h> > > #include <asm/io.h> > >@@ -469,6 +470,53 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, > > return ret; > > } > >+int walk_system_ram_res_rev(u64 start, u64 end, void *arg, > >+ int (*func)(u64, u64, void *)) > >+{ > >+ struct resource res, *rams; > >+ u64 orig_end; > >+ int count, i; > >+ int ret = -1; > >+ > >+ count = 16; /* initial */ > >+again: > >+ /* create a list */ > >+ rams = vmalloc(sizeof(struct resource) * count); > >+ if (!rams) > >+ return ret; > >+ > >+ res.start = start; > >+ res.end = end; > >+ res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > >+ orig_end = res.end; > >+ i = 0; > >+ while ((res.start < res.end) && > >+ (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { > >+ if (i >= count) { > >+ /* unlikely but */ > >+ vfree(rams); > >+ count += 16; > >+ goto again; > > Wounld't it be better to re-alloc a bigger space,copy previous values and > free the previous pointer, instead of going *again*. Okey, I will do that. Thanks, -Takahiro AKASHI > >+ } > >+ > >+ rams[i].start = res.start; > >+ rams[i++].end = res.end; > >+ > >+ res.start = res.end + 1; > >+ res.end = orig_end; > >+ } > >+ > >+ /* go reverse */ > >+ for (i--; i >= 0; i--) { > >+ ret = (*func)(rams[i].start, rams[i].end, arg); > >+ if (ret) > >+ break; > >+ } > >+ > >+ vfree(rams); > >+ return ret; > >+} > >+ > > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* > > > > -- > Regards > Pratyush
diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 6230064d7f95..9a212266299f 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -271,6 +271,9 @@ extern int walk_system_ram_res(u64 start, u64 end, void *arg, int (*func)(u64, u64, void *)); extern int +walk_system_ram_res_rev(u64 start, u64 end, void *arg, + int (*func)(u64, u64, void *)); +extern int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, void *arg, int (*func)(u64, u64, void *)); diff --git a/kernel/resource.c b/kernel/resource.c index 9b5f04404152..1d6d734c75ac 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -23,6 +23,7 @@ #include <linux/pfn.h> #include <linux/mm.h> #include <linux/resource_ext.h> +#include <linux/vmalloc.h> #include <asm/io.h> @@ -469,6 +470,53 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, return ret; } +int walk_system_ram_res_rev(u64 start, u64 end, void *arg, + int (*func)(u64, u64, void *)) +{ + struct resource res, *rams; + u64 orig_end; + int count, i; + int ret = -1; + + count = 16; /* initial */ +again: + /* create a list */ + rams = vmalloc(sizeof(struct resource) * count); + if (!rams) + return ret; + + res.start = start; + res.end = end; + res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + orig_end = res.end; + i = 0; + while ((res.start < res.end) && + (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) { + if (i >= count) { + /* unlikely but */ + vfree(rams); + count += 16; + goto again; + } + + rams[i].start = res.start; + rams[i++].end = res.end; + + res.start = res.end + 1; + res.end = orig_end; + } + + /* go reverse */ + for (i--; i >= 0; i--) { + ret = (*func)(rams[i].start, rams[i].end, arg); + if (ret) + break; + } + + vfree(rams); + return ret; +} + #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) /*
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 implementation on arm64. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> --- include/linux/ioport.h | 3 +++ kernel/resource.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+)