Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932295AbbBYWAD (ORCPT ); Wed, 25 Feb 2015 17:00:03 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:60126 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753708AbbBYV6z (ORCPT ); Wed, 25 Feb 2015 16:58:55 -0500 From: Davidlohr Bueso To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, cmetcalf@ezchip.com, Davidlohr Bueso Subject: [PATCH 1/3] tile/elf: reorganize notify_exec() Date: Wed, 25 Feb 2015 13:58:35 -0800 Message-Id: <1424901517-25069-2-git-send-email-dave@stgolabs.net> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1424901517-25069-1-git-send-email-dave@stgolabs.net> References: <1424901517-25069-1-git-send-email-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3708 Lines: 141 In the future mm->exe_file will be done without mmap_sem serialization, thus isolate and reorganize the tile elf code to make the transition easier. Good users will, make use of the more standard get_mm_exe_file(), requiring only holding the mmap_sem to read the value, and relying on reference counting to make sure that the exe file won't dissappear underneath us. The visible effects of this patch are: o We now take and drop the mmap_sem more often. Instead of just in arch_setup_additional_pages(), we also do it in: 1) get_mm_exe_file() 2) to get the mm->vm_file and notify the simulator. [Note that 1) will disappear once we change the locking rules for exe_file.] o We avoid getting a free page and doing d_path() while holding the mmap_sem. This requires reordering the checks. Cc: Chris Metcalf Signed-off-by: Davidlohr Bueso --- completely untested. arch/tile/mm/elf.c | 47 +++++++++++++++++++++++++++++------------------ 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c index 23f044e..f7ddae3 100644 --- a/arch/tile/mm/elf.c +++ b/arch/tile/mm/elf.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -39,30 +40,34 @@ static void sim_notify_exec(const char *binary_name) static int notify_exec(struct mm_struct *mm) { + int ret = 0; char *buf, *path; struct vm_area_struct *vma; + struct file *exe_file; if (!sim_is_simulator()) return 1; - if (mm->exe_file == NULL) - return 0; - - for (vma = current->mm->mmap; ; vma = vma->vm_next) { - if (vma == NULL) - return 0; - if (vma->vm_file == mm->exe_file) - break; - } - buf = (char *) __get_free_page(GFP_KERNEL); if (buf == NULL) return 0; - path = d_path(&mm->exe_file->f_path, buf, PAGE_SIZE); - if (IS_ERR(path)) { - free_page((unsigned long)buf); - return 0; + exe_file = get_mm_exe_file(mm); + if (exe_file == NULL) + goto done_free; + + path = d_path(&exe_file->f_path, buf, PAGE_SIZE); + if (IS_ERR(path)) + goto done_put; + + down_read(&mm->mmap_sem); + for (vma = current->mm->mmap; ; vma = vma->vm_next) { + if (vma == NULL) { + up_read(&mm->mmap_sem); + goto done_put; + } + if (vma->vm_file == exe_file) + break; } /* @@ -80,14 +85,20 @@ static int notify_exec(struct mm_struct *mm) __insn_mtspr(SPR_SIM_CONTROL, (SIM_CONTROL_DLOPEN | (c << _SIM_CONTROL_OPERATOR_BITS))); - if (c == '\0') + if (c == '\0') { + ret = 1; /* success */ break; + } } } + up_read(&mm->mmap_sem); sim_notify_exec(path); +done_put: + fput(exe_file); +done_free: free_page((unsigned long)buf); - return 1; + return ret; } /* Notify a running simulator, if any, that we loaded an interpreter. */ @@ -109,8 +120,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, struct mm_struct *mm = current->mm; int retval = 0; - down_write(&mm->mmap_sem); - /* * Notify the simulator that an exec just occurred. * If we can't find the filename of the mapping, just use @@ -119,6 +128,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, if (!notify_exec(mm)) sim_notify_exec(bprm->filename); + down_write(&mm->mmap_sem); + retval = setup_vdso_pages(); #ifndef __tilegx__ -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/