From patchwork Fri May 28 11:39:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jia He X-Patchwork-Id: 12286817 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AE21C4708C for ; Fri, 28 May 2021 11:40:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B2D3613D1 for ; Fri, 28 May 2021 11:40:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235763AbhE1Lly (ORCPT ); Fri, 28 May 2021 07:41:54 -0400 Received: from foss.arm.com ([217.140.110.172]:39654 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233583AbhE1Llu (ORCPT ); Fri, 28 May 2021 07:41:50 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0A0241516; Fri, 28 May 2021 04:40:16 -0700 (PDT) Received: from entos-ampere-02.shanghai.arm.com (entos-ampere-02.shanghai.arm.com [10.169.214.103]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CA0963F73B; Fri, 28 May 2021 04:40:09 -0700 (PDT) From: Jia He To: Linus Torvalds , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Jonathan Corbet , Alexander Viro , Luca Coelho , Kalle Valo , "David S. Miller" , Jakub Kicinski , Heiko Carstens , Vasily Gorbik Cc: Christian Borntraeger , Johannes Berg , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, Jia He Subject: [PATCH RFCv2 1/3] fs: introduce helper d_path_fast() Date: Fri, 28 May 2021 19:39:49 +0800 Message-Id: <20210528113951.6225-2-justin.he@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210528113951.6225-1-justin.he@arm.com> References: <20210528113951.6225-1-justin.he@arm.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-State: RFC This helper is similar to d_path except that it doesn't take any seqlock/spinlock. It is typical for debugging purpose. Signed-off-by: Jia He --- fs/d_path.c | 21 +++++++++++++++++++++ include/linux/dcache.h | 1 + 2 files changed, 22 insertions(+) diff --git a/fs/d_path.c b/fs/d_path.c index 23a53f7b5c71..f9df68d62786 100644 --- a/fs/d_path.c +++ b/fs/d_path.c @@ -263,6 +263,27 @@ char *d_path(const struct path *path, char *buf, int buflen) } EXPORT_SYMBOL(d_path); +/** + * d_path_fast - fast return the full path of a dentry without taking + * any seqlock/spinlock. This helper is typical for debugging purpose + */ +char *d_path_fast(const struct path *path, char *buf, int buflen) +{ + struct path root; + struct mount *mnt = real_mount(path->mnt); + DECLARE_BUFFER(b, buf, buflen); + + rcu_read_lock(); + get_fs_root_rcu(current->fs, &root); + + prepend(&b, "", 1); + __prepend_path(path->dentry, mnt, &root, &b); + rcu_read_unlock(); + + return extract_string(&b); +} +EXPORT_SYMBOL(d_path_fast); + /* * Helper function for dentry_operations.d_dname() members */ diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 9e23d33bb6f1..c4483fc887a5 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -301,6 +301,7 @@ char *dynamic_dname(struct dentry *, char *, int, const char *, ...); extern char *__d_path(const struct path *, const struct path *, char *, int); extern char *d_absolute_path(const struct path *, char *, int); extern char *d_path(const struct path *, char *, int); +extern char *d_path_fast(const struct path *, char *, int); extern char *dentry_path_raw(const struct dentry *, char *, int); extern char *dentry_path(const struct dentry *, char *, int); From patchwork Fri May 28 11:39:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jia He X-Patchwork-Id: 12286819 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C3E2C47087 for ; Fri, 28 May 2021 11:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F54F6124B for ; Fri, 28 May 2021 11:40:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234558AbhE1LmG (ORCPT ); Fri, 28 May 2021 07:42:06 -0400 Received: from foss.arm.com ([217.140.110.172]:39690 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235632AbhE1Ll5 (ORCPT ); Fri, 28 May 2021 07:41:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B9AC8168F; Fri, 28 May 2021 04:40:22 -0700 (PDT) Received: from entos-ampere-02.shanghai.arm.com (entos-ampere-02.shanghai.arm.com [10.169.214.103]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 889003F73B; Fri, 28 May 2021 04:40:16 -0700 (PDT) From: Jia He To: Linus Torvalds , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Jonathan Corbet , Alexander Viro , Luca Coelho , Kalle Valo , "David S. Miller" , Jakub Kicinski , Heiko Carstens , Vasily Gorbik Cc: Christian Borntraeger , Johannes Berg , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, Jia He Subject: [PATCH RFCv2 2/3] lib/vsprintf.c: make %pD print full path for file Date: Fri, 28 May 2021 19:39:50 +0800 Message-Id: <20210528113951.6225-3-justin.he@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210528113951.6225-1-justin.he@arm.com> References: <20210528113951.6225-1-justin.he@arm.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-State: RFC We have '%pD' for printing a filename. It may not be perfect (by default it only prints one component.) As suggested by Linus at [1]: A dentry has a parent, but at the same time, a dentry really does inherently have "one name" (and given just the dentry pointers, you can't show mount-related parenthood, so in many ways the "show just one name" makes sense for "%pd" in ways it doesn't necessarily for "%pD"). But while a dentry arguably has that "one primary component", a _file_ is certainly not exclusively about that last component. Hence "file_dentry_name()" simply shouldn't use "dentry_name()" at all. Despite that shared code origin, and despite that similar letter choice (lower-vs-upper case), a dentry and a file really are very different from a name standpoint. Here stack space is preferred for file_d_path_name() because it is much safer. The stack size 256 is a compromise between stack overflow and too short full path. [1] https://lore.kernel.org/lkml/CAHk-=wimsMqGdzik187YWLb-ru+iktb4MYbMQG1rnZ81dXYFVg@mail.gmail.com/ Suggested-by: Linus Torvalds Signed-off-by: Jia He --- Documentation/core-api/printk-formats.rst | 5 +++-- lib/vsprintf.c | 21 +++++++++++++++++---- 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index f063a384c7c8..95ba14dc529b 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -408,12 +408,13 @@ dentry names :: %pd{,2,3,4} - %pD{,2,3,4} + %pD For printing dentry name; if we race with :c:func:`d_move`, the name might be a mix of old and new ones, but it won't oops. %pd dentry is a safer equivalent of %s dentry->d_name.name we used to use, %pd prints ``n`` -last components. %pD does the same thing for struct file. +last components. %pD prints full file path together with mount-related +parenthood. Passed by reference. diff --git a/lib/vsprintf.c b/lib/vsprintf.c index f0c35d9b65bf..2e5387b08d67 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -920,13 +921,25 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp } static noinline_for_stack -char *file_dentry_name(char *buf, char *end, const struct file *f, +char *file_d_path_name(char *buf, char *end, const struct file *f, struct printf_spec spec, const char *fmt) { + const struct path *path; + char *p; + char full_path[256]; + if (check_pointer(&buf, end, f, spec)) return buf; - return dentry_name(buf, end, f->f_path.dentry, spec, fmt); + path = &f->f_path; + if (check_pointer(&buf, end, path, spec)) + return buf; + + p = d_path_fast(path, full_path, sizeof(full_path)); + if (IS_ERR(p)) + return err_ptr(buf, end, p, spec); + + return string_nocheck(buf, end, p, spec); } #ifdef CONFIG_BLOCK static noinline_for_stack @@ -2296,7 +2309,7 @@ early_param("no_hash_pointers", no_hash_pointers_enable); * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives * (default assumed to be phys_addr_t, passed by reference) * - 'd[234]' For a dentry name (optionally 2-4 last components) - * - 'D[234]' Same as 'd' but for a struct file + * - 'D' For full path name of a struct file * - 'g' For block_device name (gendisk + partition number) * - 't[RT][dt][r]' For time and date as represented by: * R struct rtc_time @@ -2395,7 +2408,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'C': return clock(buf, end, ptr, spec, fmt); case 'D': - return file_dentry_name(buf, end, ptr, spec, fmt); + return file_d_path_name(buf, end, ptr, spec, fmt); #ifdef CONFIG_BLOCK case 'g': return bdev_name(buf, end, ptr, spec, fmt); From patchwork Fri May 28 11:39:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jia He X-Patchwork-Id: 12286821 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A090BC4708D for ; Fri, 28 May 2021 11:40:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84CE5613D1 for ; Fri, 28 May 2021 11:40:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236136AbhE1LmX (ORCPT ); Fri, 28 May 2021 07:42:23 -0400 Received: from foss.arm.com ([217.140.110.172]:39720 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234556AbhE1LmE (ORCPT ); Fri, 28 May 2021 07:42:04 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 765F41691; Fri, 28 May 2021 04:40:29 -0700 (PDT) Received: from entos-ampere-02.shanghai.arm.com (entos-ampere-02.shanghai.arm.com [10.169.214.103]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4424F3F73B; Fri, 28 May 2021 04:40:23 -0700 (PDT) From: Jia He To: Linus Torvalds , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Jonathan Corbet , Alexander Viro , Luca Coelho , Kalle Valo , "David S. Miller" , Jakub Kicinski , Heiko Carstens , Vasily Gorbik Cc: Christian Borntraeger , Johannes Berg , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, Jia He Subject: [PATCH RFCv2 3/3] s390/hmcdrv: remove the redundant directory path in debug message Date: Fri, 28 May 2021 19:39:51 +0800 Message-Id: <20210528113951.6225-4-justin.he@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210528113951.6225-1-justin.he@arm.com> References: <20210528113951.6225-1-justin.he@arm.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-State: RFC It would be better to use full file path with '%pD' instead of hard coding. Signed-off-by: Jia He --- drivers/s390/char/hmcdrv_dev.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/s390/char/hmcdrv_dev.c b/drivers/s390/char/hmcdrv_dev.c index 20e9cd542e03..cdde75508c8a 100644 --- a/drivers/s390/char/hmcdrv_dev.c +++ b/drivers/s390/char/hmcdrv_dev.c @@ -137,7 +137,7 @@ static int hmcdrv_dev_open(struct inode *inode, struct file *fp) if (rc) module_put(THIS_MODULE); - pr_debug("open file '/dev/%pD' with return code %d\n", fp, rc); + pr_debug("open file '%pD' with return code %d\n", fp, rc); return rc; } @@ -146,7 +146,7 @@ static int hmcdrv_dev_open(struct inode *inode, struct file *fp) */ static int hmcdrv_dev_release(struct inode *inode, struct file *fp) { - pr_debug("closing file '/dev/%pD'\n", fp); + pr_debug("closing file '%pD'\n", fp); kfree(fp->private_data); fp->private_data = NULL; hmcdrv_ftp_shutdown(); @@ -231,7 +231,7 @@ static ssize_t hmcdrv_dev_read(struct file *fp, char __user *ubuf, retlen = hmcdrv_dev_transfer((char *) fp->private_data, *pos, ubuf, len); - pr_debug("read from file '/dev/%pD' at %lld returns %zd/%zu\n", + pr_debug("read from file '%pD' at %lld returns %zd/%zu\n", fp, (long long) *pos, retlen, len); if (retlen > 0) @@ -248,7 +248,7 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf, { ssize_t retlen; - pr_debug("writing file '/dev/%pD' at pos. %lld with length %zd\n", + pr_debug("writing file '%pD' at pos. %lld with length %zd\n", fp, (long long) *pos, len); if (!fp->private_data) { /* first expect a cmd write */ @@ -272,7 +272,7 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf, if (retlen > 0) *pos += retlen; - pr_debug("write to file '/dev/%pD' returned %zd\n", fp, retlen); + pr_debug("write to file '%pD' returned %zd\n", fp, retlen); return retlen; }