| Message ID | 20171002061431.11117-3-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Takahiro, On 02/10/17 07:14, 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 | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 62 insertions(+) > > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > index f5cf32e80041..62eb62b98118 100644 > --- a/include/linux/ioport.h > +++ b/include/linux/ioport.h > @@ -273,6 +273,9 @@ 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..572f2f91ce9c 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> > > > @@ -469,6 +471,63 @@ 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; nit: Why do you need orig_end? From what I can tell it is always equal to the "end" parameter of the function. If you think having orig_end makes it clearer to distinguish "end" from "res.end" could we declare it as: const u64 orig_end = end; Making it clear it is an alias? > + int count, i; > + int ret = -1; > + > + count = 16; /* initial */ nit: This doesn't represent the number of element we found but the size of the rams array. Would it be better named something like "rams_size"? > + > + /* 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) { > + /* re-alloc */ > + struct resource *rams_new; > + int count_new; > + > + count_new = count + 16; > + rams_new = vmalloc(sizeof(struct resource) * count_new); > + if (!rams_new) > + goto out; Should we return -ENOMEM? > + > + memcpy(rams_new, rams, count); We are likely to lose data here. -> memcpy(rams_new, rams, count * sizeof(struct resourse)); Also, if vremalloc doesn't exist maybe the realloc part could still be put in a separate function? > + vfree(rams); > + rams = rams_new; > + count = count_new; > + } > + > + 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; > + } > + > +out: > + vfree(rams); > + return ret; > +} > + > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* > Cheers,
Hi Julien, On Thu, Oct 05, 2017 at 10:36:47AM +0100, Julien Thierry wrote: > Hi Takahiro, > > On 02/10/17 07:14, 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 | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 62 insertions(+) > > > >diff --git a/include/linux/ioport.h b/include/linux/ioport.h > >index f5cf32e80041..62eb62b98118 100644 > >--- a/include/linux/ioport.h > >+++ b/include/linux/ioport.h > >@@ -273,6 +273,9 @@ 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..572f2f91ce9c 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> > >@@ -469,6 +471,63 @@ 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; > > nit: > Why do you need orig_end? From what I can tell it is always equal to the > "end" parameter of the function. Right, but all the other functions, including walk_system_ram_res() and walk_iomem_res_desc(), use orig_end in the exact same way. > If you think having orig_end makes it clearer to distinguish "end" from > "res.end" could we declare it as: > > const u64 orig_end = end; > > Making it clear it is an alias? That said, I will remove orig_end from my function. > >+ int count, i; > >+ int ret = -1; > >+ > >+ count = 16; /* initial */ > > nit: > This doesn't represent the number of element we found but the size of the > rams array. > Would it be better named something like "rams_size"? Okay > >+ > >+ /* 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) { > >+ /* re-alloc */ > >+ struct resource *rams_new; > >+ int count_new; > >+ > >+ count_new = count + 16; > >+ rams_new = vmalloc(sizeof(struct resource) * count_new); > >+ if (!rams_new) > >+ goto out; > > Should we return -ENOMEM? Well, I'd like to keep the current code as all the other variants just return -1 for error. > >+ > >+ memcpy(rams_new, rams, count); > > We are likely to lose data here. > > -> memcpy(rams_new, rams, count * sizeof(struct resourse)); Oops, thanks. > Also, if vremalloc doesn't exist maybe the realloc part could still be put > in a separate function? Next time :) Thanks, -Takahiro AKASHI > >+ vfree(rams); > >+ rams = rams_new; > >+ count = count_new; > >+ } > >+ > >+ 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; > >+ } > >+ > >+out: > >+ vfree(rams); > >+ return ret; > >+} > >+ > > #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) > > /* > > > > Cheers, > > -- > Julien Thierry
diff --git a/include/linux/ioport.h b/include/linux/ioport.h index f5cf32e80041..62eb62b98118 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -273,6 +273,9 @@ 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..572f2f91ce9c 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> @@ -469,6 +471,63 @@ 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 */ + + /* 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) { + /* re-alloc */ + struct resource *rams_new; + int count_new; + + count_new = count + 16; + rams_new = vmalloc(sizeof(struct resource) * count_new); + if (!rams_new) + goto out; + + memcpy(rams_new, rams, count); + vfree(rams); + rams = rams_new; + count = count_new; + } + + 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; + } + +out: + 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 | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+)