Hi Andrew, I am sorry to repost this kind of trivial cleanup for the 4th time, but after recent discussion (https://lkml.org/lkml/2011/5/3/323) with Hugh I think that it makes sense to keep the original expand_{upwards,downwards} without being explicit about the stack in the name. As Hugh pointed out, IA64 uses expand_upwards for something that is not really a stack (it is a backing storage for registers). The following patch reworks the original one so it is not incremental. If you prefer incremental one I can send that one instead. Just for record this patch obsoletes: mm-make-expand_downwards-symmetrical-with-expand_upwards.patch mm-make-expand_downwards-symmetrical-with-expand_upwards-v3.patch in your current (2011-04-29-16-25) mm tree. --- >From 1b679558f464530c59c93930b958a3436a250c25 Mon Sep 17 00:00:00 2001 From: Michal Hocko <mhocko@xxxxxxx> Date: Fri, 15 Apr 2011 14:56:26 +0200 Subject: [PATCH] mm: make expand_downwards symmetrical to expand_upwards Currently we have expand_upwards exported while expand_downwards is accessible only via expand_stack or expand_stack_downwards. check_stack_guard_page is a nice example of the asymmetry. It uses expand_stack for VM_GROWSDOWN while expand_upwards is called for VM_GROWSUP case. Let's clean this up by exporting both functions and make those names consistent. Let's use expand_{upwards,downwards} because expanding doesn't always involve stack manipulation (an example is ia64_do_page_fault which uses expand_upwards for registers backing store expansion). expand_downwards has to be defined for both CONFIG_STACK_GROWS{UP,DOWN} because get_arg_page calls the downwards version in the early process initialization phase for growsup configuration. CC: Hugh Dickins <hughd@xxxxxxxxxx> Signed-off-by: Michal Hocko <mhocko@xxxxxxx> --- fs/exec.c | 2 +- include/linux/mm.h | 8 +++++--- mm/memory.c | 2 +- mm/mmap.c | 7 +------ 4 files changed, 8 insertions(+), 11 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 5e62d26..c2668ff 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -194,7 +194,7 @@ struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, #ifdef CONFIG_STACK_GROWSUP if (write) { - ret = expand_stack_downwards(bprm->vma, pos); + ret = expand_downwards(bprm->vma, pos); if (ret < 0) return NULL; } diff --git a/include/linux/mm.h b/include/linux/mm.h index 692dbae..2d4f62b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1494,15 +1494,17 @@ unsigned long ra_submit(struct file_ra_state *ra, struct address_space *mapping, struct file *filp); -/* Do stack extension */ +/* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */ extern int expand_stack(struct vm_area_struct *vma, unsigned long address); + +/* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */ +extern int expand_downwards(struct vm_area_struct *vma, + unsigned long address); #if VM_GROWSUP extern int expand_upwards(struct vm_area_struct *vma, unsigned long address); #else #define expand_upwards(vma, address) do { } while (0) #endif -extern int expand_stack_downwards(struct vm_area_struct *vma, - unsigned long address); /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr); diff --git a/mm/memory.c b/mm/memory.c index ce22a25..f404fb6 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2969,7 +2969,7 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo if (prev && prev->vm_end == address) return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; - expand_stack(vma, address - PAGE_SIZE); + expand_downwards(vma, address - PAGE_SIZE); } if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { struct vm_area_struct *next = vma->vm_next; diff --git a/mm/mmap.c b/mm/mmap.c index e27e0cf..4c10287 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1782,7 +1782,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) /* * vma is the first one with address < vma->vm_start. Have to extend vma. */ -static int expand_downwards(struct vm_area_struct *vma, +int expand_downwards(struct vm_area_struct *vma, unsigned long address) { int error; @@ -1829,11 +1829,6 @@ static int expand_downwards(struct vm_area_struct *vma, return error; } -int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address) -{ - return expand_downwards(vma, address); -} - #ifdef CONFIG_STACK_GROWSUP int expand_stack(struct vm_area_struct *vma, unsigned long address) { -- 1.7.4.4 -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>