The patch titled memcg: fix ugly initialization of return value is in caller has been added to the -mm tree. Its filename is memcg-fix-ugly-initialization-of-return-value-is-in-caller.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: memcg: fix ugly initialization of return value is in caller From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Remove initialization of vaiable in caller of memory cgroup function. Actually, it's return value of memcg function but it's initialized in caller. Some memory cgroup uses following style to bring the result of start function to the end function for avoiding races. mem_cgroup_start_A(&(*ptr)) /* Something very complicated can happen here. */ mem_cgroup_end_A(*ptr) In some calls, *ptr should be initialized to NULL be caller. But it's ugly. This patch fixes that *ptr is initialized by _start function. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 8 ++++++-- mm/memory.c | 2 +- mm/migrate.c | 2 +- mm/swapfile.c | 2 +- 4 files changed, 9 insertions(+), 5 deletions(-) diff -puN mm/memcontrol.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller mm/memcontrol.c --- a/mm/memcontrol.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller +++ a/mm/memcontrol.c @@ -2413,7 +2413,7 @@ int mem_cgroup_cache_charge(struct page /* shmem */ if (PageSwapCache(page)) { - struct mem_cgroup *mem = NULL; + struct mem_cgroup *mem; ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); if (!ret) @@ -2439,6 +2439,8 @@ int mem_cgroup_try_charge_swapin(struct struct mem_cgroup *mem; int ret; + *ptr = NULL; + if (mem_cgroup_disabled()) return 0; @@ -2854,6 +2856,8 @@ int mem_cgroup_prepare_migration(struct enum charge_type ctype; int ret = 0; + *ptr = NULL; + VM_BUG_ON(PageTransHuge(page)); if (mem_cgroup_disabled()) return 0; @@ -2996,7 +3000,7 @@ int mem_cgroup_shmem_charge_fallback(str struct mm_struct *mm, gfp_t gfp_mask) { - struct mem_cgroup *mem = NULL; + struct mem_cgroup *mem; int ret; if (mem_cgroup_disabled()) diff -puN mm/memory.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller mm/memory.c --- a/mm/memory.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller +++ a/mm/memory.c @@ -2707,7 +2707,7 @@ static int do_swap_page(struct mm_struct swp_entry_t entry; pte_t pte; int locked; - struct mem_cgroup *ptr = NULL; + struct mem_cgroup *ptr; int exclusive = 0; int ret = 0; diff -puN mm/migrate.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller mm/migrate.c --- a/mm/migrate.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller +++ a/mm/migrate.c @@ -623,7 +623,7 @@ static int unmap_and_move(new_page_t get struct page *newpage = get_new_page(page, private, &result); int remap_swapcache = 1; int charge = 0; - struct mem_cgroup *mem = NULL; + struct mem_cgroup *mem; struct anon_vma *anon_vma = NULL; if (!newpage) diff -puN mm/swapfile.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller mm/swapfile.c --- a/mm/swapfile.c~memcg-fix-ugly-initialization-of-return-value-is-in-caller +++ a/mm/swapfile.c @@ -880,7 +880,7 @@ unsigned int count_swap_pages(int type, static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, swp_entry_t entry, struct page *page) { - struct mem_cgroup *ptr = NULL; + struct mem_cgroup *ptr; spinlock_t *ptl; pte_t *pte; int ret = 1; _ Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are origin.patch memsw-handle-swapaccount-kernel-parameter-correctly.patch memsw-deprecate-noswapaccount-kernel-parameter-and-schedule-it-for-removal.patch oom-suppress-nodes-that-are-not-allowed-from-meminfo-on-oom-kill.patch oom-suppress-show_mem-for-many-nodes-in-irq-context-on-page-alloc-failure.patch oom-suppress-nodes-that-are-not-allowed-from-meminfo-on-page-alloc-failure.patch mm-add-replace_page_cache_page-function.patch memcg-fix-ugly-initialization-of-return-value-is-in-caller.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html