From a62c34bd2a8a3f159945becd57401e478818d51c Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 19 May 2014 15:58:33 -0700 Subject: x86, mm: Improve _install_special_mapping and fix x86 vdso naming Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov Cc: Pavel Emelyanov Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- mm/mmap.c | 89 ++++++++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 60 insertions(+), 29 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index b1202cf81f4b..52bbc9514d9d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2872,6 +2872,31 @@ int may_expand_vm(struct mm_struct *mm, unsigned long npages) return 1; } +static int special_mapping_fault(struct vm_area_struct *vma, + struct vm_fault *vmf); + +/* + * Having a close hook prevents vma merging regardless of flags. + */ +static void special_mapping_close(struct vm_area_struct *vma) +{ +} + +static const char *special_mapping_name(struct vm_area_struct *vma) +{ + return ((struct vm_special_mapping *)vma->vm_private_data)->name; +} + +static const struct vm_operations_struct special_mapping_vmops = { + .close = special_mapping_close, + .fault = special_mapping_fault, + .name = special_mapping_name, +}; + +static const struct vm_operations_struct legacy_special_mapping_vmops = { + .close = special_mapping_close, + .fault = special_mapping_fault, +}; static int special_mapping_fault(struct vm_area_struct *vma, struct vm_fault *vmf) @@ -2887,7 +2912,13 @@ static int special_mapping_fault(struct vm_area_struct *vma, */ pgoff = vmf->pgoff - vma->vm_pgoff; - for (pages = vma->vm_private_data; pgoff && *pages; ++pages) + if (vma->vm_ops == &legacy_special_mapping_vmops) + pages = vma->vm_private_data; + else + pages = ((struct vm_special_mapping *)vma->vm_private_data)-> + pages; + + for (; pgoff && *pages; ++pages) pgoff--; if (*pages) { @@ -2900,30 +2931,11 @@ static int special_mapping_fault(struct vm_area_struct *vma, return VM_FAULT_SIGBUS; } -/* - * Having a close hook prevents vma merging regardless of flags. - */ -static void special_mapping_close(struct vm_area_struct *vma) -{ -} - -static const struct vm_operations_struct special_mapping_vmops = { - .close = special_mapping_close, - .fault = special_mapping_fault, -}; - -/* - * Called with mm->mmap_sem held for writing. - * Insert a new vma covering the given region, with the given flags. - * Its pages are supplied by the given array of struct page *. - * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. - * The region past the last page supplied will always produce SIGBUS. - * The array pointer and the pages it points to are assumed to stay alive - * for as long as this mapping might exist. - */ -struct vm_area_struct *_install_special_mapping(struct mm_struct *mm, - unsigned long addr, unsigned long len, - unsigned long vm_flags, struct page **pages) +static struct vm_area_struct *__install_special_mapping( + struct mm_struct *mm, + unsigned long addr, unsigned long len, + unsigned long vm_flags, const struct vm_operations_struct *ops, + void *priv) { int ret; struct vm_area_struct *vma; @@ -2940,8 +2952,8 @@ struct vm_area_struct *_install_special_mapping(struct mm_struct *mm, vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); - vma->vm_ops = &special_mapping_vmops; - vma->vm_private_data = pages; + vma->vm_ops = ops; + vma->vm_private_data = priv; ret = insert_vm_struct(mm, vma); if (ret) @@ -2958,12 +2970,31 @@ out: return ERR_PTR(ret); } +/* + * Called with mm->mmap_sem held for writing. + * Insert a new vma covering the given region, with the given flags. + * Its pages are supplied by the given array of struct page *. + * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. + * The region past the last page supplied will always produce SIGBUS. + * The array pointer and the pages it points to are assumed to stay alive + * for as long as this mapping might exist. + */ +struct vm_area_struct *_install_special_mapping( + struct mm_struct *mm, + unsigned long addr, unsigned long len, + unsigned long vm_flags, const struct vm_special_mapping *spec) +{ + return __install_special_mapping(mm, addr, len, vm_flags, + &special_mapping_vmops, (void *)spec); +} + int install_special_mapping(struct mm_struct *mm, unsigned long addr, unsigned long len, unsigned long vm_flags, struct page **pages) { - struct vm_area_struct *vma = _install_special_mapping(mm, - addr, len, vm_flags, pages); + struct vm_area_struct *vma = __install_special_mapping( + mm, addr, len, vm_flags, &legacy_special_mapping_vmops, + (void *)pages); if (IS_ERR(vma)) return PTR_ERR(vma); -- cgit v1.2.3 From 14bd5b458bf62f84b2639ae288fd83d1da7a9af6 Mon Sep 17 00:00:00 2001 From: Duan Jiong Date: Wed, 4 Jun 2014 16:07:05 -0700 Subject: mm/mmap.c: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO Fix a coccinelle error regarding usage of IS_ERR and PTR_ERR instead of PTR_ERR_OR_ZERO. Signed-off-by: Duan Jiong Acked-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index b1202cf81f4b..6cdec3a6f4bf 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2965,9 +2965,7 @@ int install_special_mapping(struct mm_struct *mm, struct vm_area_struct *vma = _install_special_mapping(mm, addr, len, vm_flags, pages); - if (IS_ERR(vma)) - return PTR_ERR(vma); - return 0; + return PTR_ERR_OR_ZERO(vma); } static DEFINE_MUTEX(mm_all_locks_mutex); -- cgit v1.2.3 From 64ac4940d557df8caab602eaea679ec7eaf9a57f Mon Sep 17 00:00:00 2001 From: Huang Shijie Date: Wed, 4 Jun 2014 16:07:33 -0700 Subject: mm/mmap.c: remove the first mapping check Remove the first mapping check for vma_link. Move the mutex_lock into the braces when vma->vm_file is true. Signed-off-by: Huang Shijie Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index 6cdec3a6f4bf..8a56d39df4ed 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -640,11 +640,10 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, { struct address_space *mapping = NULL; - if (vma->vm_file) + if (vma->vm_file) { mapping = vma->vm_file->f_mapping; - - if (mapping) mutex_lock(&mapping->i_mmap_mutex); + } __vma_link(mm, vma, prev, rb_link, rb_parent); __vma_link_file(vma); -- cgit v1.2.3 From b1de0d139c97a6078bbada6cf2d27c30ce127a97 Mon Sep 17 00:00:00 2001 From: Mitchel Humpherys Date: Fri, 6 Jun 2014 14:38:30 -0700 Subject: mm: convert some level-less printks to pr_* printk is meant to be used with an associated log level. There are some instances of printk scattered around the mm code where the log level is missing. Add a log level and adhere to suggestions by scripts/checkpatch.pl by moving to the pr_* macros. Also add the typical pr_fmt definition so that print statements can be easily traced back to the modules where they occur, correlated one with another, etc. This will require the removal of some (now redundant) prefixes on a few print statements. Signed-off-by: Mitchel Humpherys Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index ced5efcdd4b6..129b847d30cc 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -6,6 +6,8 @@ * Address space accounting code */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include #include #include @@ -37,6 +39,7 @@ #include #include #include +#include #include #include @@ -361,20 +364,20 @@ static int browse_rb(struct rb_root *root) struct vm_area_struct *vma; vma = rb_entry(nd, struct vm_area_struct, vm_rb); if (vma->vm_start < prev) { - printk("vm_start %lx prev %lx\n", vma->vm_start, prev); + pr_info("vm_start %lx prev %lx\n", vma->vm_start, prev); bug = 1; } if (vma->vm_start < pend) { - printk("vm_start %lx pend %lx\n", vma->vm_start, pend); + pr_info("vm_start %lx pend %lx\n", vma->vm_start, pend); bug = 1; } if (vma->vm_start > vma->vm_end) { - printk("vm_end %lx < vm_start %lx\n", + pr_info("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); bug = 1; } if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { - printk("free gap %lx, correct %lx\n", + pr_info("free gap %lx, correct %lx\n", vma->rb_subtree_gap, vma_compute_subtree_gap(vma)); bug = 1; @@ -388,7 +391,7 @@ static int browse_rb(struct rb_root *root) for (nd = pn; nd; nd = rb_prev(nd)) j++; if (i != j) { - printk("backwards %d, forwards %d\n", j, i); + pr_info("backwards %d, forwards %d\n", j, i); bug = 1; } return bug ? -1 : i; @@ -423,17 +426,17 @@ static void validate_mm(struct mm_struct *mm) i++; } if (i != mm->map_count) { - printk("map_count %d vm_next %d\n", mm->map_count, i); + pr_info("map_count %d vm_next %d\n", mm->map_count, i); bug = 1; } if (highest_address != mm->highest_vm_end) { - printk("mm->highest_vm_end %lx, found %lx\n", + pr_info("mm->highest_vm_end %lx, found %lx\n", mm->highest_vm_end, highest_address); bug = 1; } i = browse_rb(&mm->mm_rb); if (i != mm->map_count) { - printk("map_count %d rb %d\n", mm->map_count, i); + pr_info("map_count %d rb %d\n", mm->map_count, i); bug = 1; } BUG_ON(bug); @@ -3280,7 +3283,7 @@ static struct notifier_block reserve_mem_nb = { static int __meminit init_reserve_notifier(void) { if (register_hotmemory_notifier(&reserve_mem_nb)) - printk("Failed registering memory add/remove notifier for admin reserve"); + pr_err("Failed registering memory add/remove notifier for admin reserve\n"); return 0; } -- cgit v1.2.3