On 02/27/18 at 01:48pm, AKASHI Takahiro wrote: > While CRASH_MAX_RANGES (== 16) seems to be good enough, fixed-number > array is not a good idea in general. > > In this patch, size of crash_mem buffer is calculated as before and > the buffer is now dynamically allocated. This change also allows removing > crash_elf_data structure. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> > Cc: Dave Young <dyoung@xxxxxxxxxx> > Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> > Cc: Baoquan He <bhe@xxxxxxxxxx> > --- > arch/x86/kernel/crash.c | 80 ++++++++++++++++++------------------------------- > 1 file changed, 29 insertions(+), 51 deletions(-) > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index 913fd8021f8a..bfc37ad20d4a 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -41,32 +41,14 @@ > /* Alignment required for elf header segment */ > #define ELF_CORE_HEADER_ALIGN 4096 > > -/* This primarily represents number of split ranges due to exclusion */ > -#define CRASH_MAX_RANGES 16 > - > struct crash_mem_range { > u64 start, end; > }; > > struct crash_mem { > - unsigned int nr_ranges; > - struct crash_mem_range ranges[CRASH_MAX_RANGES]; > -}; > - > -/* Misc data about ram ranges needed to prepare elf headers */ > -struct crash_elf_data { > - struct kimage *image; > - /* > - * Total number of ram ranges we have after various adjustments for > - * crash reserved region, etc. > - */ > unsigned int max_nr_ranges; > - > - /* Pointer to elf header */ > - void *ehdr; > - /* Pointer to next phdr */ > - void *bufp; > - struct crash_mem mem; > + unsigned int nr_ranges; > + struct crash_mem_range ranges[0]; > }; > > /* Used while preparing memory map entries for second kernel */ > @@ -217,26 +199,29 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) > return 0; > } > > - > /* Gather all the required information to prepare elf headers for ram regions */ > -static void fill_up_crash_elf_data(struct crash_elf_data *ced, > - struct kimage *image) > +static struct crash_mem *fill_up_crash_elf_data(void) > { > unsigned int nr_ranges = 0; > - > - ced->image = image; > + struct crash_mem *cmem; > > walk_system_ram_res(0, -1, &nr_ranges, > get_nr_ram_ranges_callback); I know it is probably not possible fail here, but for safe we can check if nr_ranges == 0 > > - ced->max_nr_ranges = nr_ranges; > + /* > + * Exclusion of crash region and/or crashk_low_res may cause > + * another range split. So add extra two slots here. > + */ > + nr_ranges += 2; > + cmem = vmalloc(sizeof(struct crash_mem) + > + sizeof(struct crash_mem_range) * nr_ranges); > + if (!cmem) > + return NULL; vzalloc will be better. > > - /* Exclusion of crash region could split memory ranges */ > - ced->max_nr_ranges++; > + cmem->max_nr_ranges = nr_ranges; > + cmem->nr_ranges = 0; > > - /* If crashk_low_res is not 0, another range split possible */ > - if (crashk_low_res.end) > - ced->max_nr_ranges++; > + return cmem; > } > > static int exclude_mem_range(struct crash_mem *mem, > @@ -293,10 +278,8 @@ static int exclude_mem_range(struct crash_mem *mem, > return 0; > > /* Split happened */ > - if (i == CRASH_MAX_RANGES - 1) { > - pr_err("Too many crash ranges after split\n"); > + if (i == mem->max_nr_ranges - 1) > return -ENOMEM; > - } > > /* Location where new range should go */ > j = i + 1; > @@ -314,11 +297,10 @@ static int exclude_mem_range(struct crash_mem *mem, > > /* > * Look for any unwanted ranges between mstart, mend and remove them. This > - * might lead to split and split ranges are put in ced->mem.ranges[] array > + * might lead to split and split ranges are put in cmem->ranges[] array > */ > -static int elf_header_exclude_ranges(struct crash_elf_data *ced) > +static int elf_header_exclude_ranges(struct crash_mem *cmem) > { > - struct crash_mem *cmem = &ced->mem; > int ret = 0; > > /* Exclude crashkernel region */ > @@ -337,8 +319,7 @@ static int elf_header_exclude_ranges(struct crash_elf_data *ced) > > static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) > { > - struct crash_elf_data *ced = arg; > - struct crash_mem *cmem = &ced->mem; > + struct crash_mem *cmem = arg; > > cmem->ranges[cmem->nr_ranges].start = res->start; > cmem->ranges[cmem->nr_ranges].end = res->end; > @@ -347,7 +328,7 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) > return 0; > } > > -static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > +static int prepare_elf64_headers(struct crash_mem *cmem, int kernel_map, > void **addr, unsigned long *sz) > { > Elf64_Ehdr *ehdr; > @@ -356,12 +337,11 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > unsigned char *buf, *bufp; > unsigned int cpu, i; > unsigned long long notes_addr; > - struct crash_mem *cmem = &ced->mem; > unsigned long mstart, mend; > > /* extra phdr for vmcoreinfo elf note */ > nr_phdr = nr_cpus + 1; > - nr_phdr += ced->max_nr_ranges; > + nr_phdr += cmem->nr_ranges; > > /* > * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping > @@ -455,29 +435,27 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, int kernel_map, > static int prepare_elf_headers(struct kimage *image, void **addr, > unsigned long *sz) > { > - struct crash_elf_data *ced; > + struct crash_mem *cmem; > Elf64_Ehdr *ehdr; > Elf64_Phdr *phdr; > int ret, i; > > - ced = kzalloc(sizeof(*ced), GFP_KERNEL); > - if (!ced) > + cmem = fill_up_crash_elf_data(); > + if (!cmem) > return -ENOMEM; > > - fill_up_crash_elf_data(ced, image); > - > - ret = walk_system_ram_res(0, -1, ced, > + ret = walk_system_ram_res(0, -1, cmem, > prepare_elf64_ram_headers_callback); > if (ret) > goto out; > > /* Exclude unwanted mem ranges */ > - ret = elf_header_exclude_ranges(ced); > + ret = elf_header_exclude_ranges(cmem); > if (ret) > goto out; > > /* By default prepare 64bit headers */ > - ret = prepare_elf64_headers(ced, > + ret = prepare_elf64_headers(cmem, > (int)IS_ENABLED(CONFIG_X86_64), addr, sz); > if (ret) > goto out; > @@ -496,7 +474,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr, > break; > } > out: > - kfree(ced); > + vfree(cmem); > return ret; > } > > -- > 2.16.2 > Thanks Dave -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html