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[35.169.212.159]) by smtp.gmail.com with ESMTPSA id 18sm16043166qkr.90.2021.03.30.02.59.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Mar 2021 03:00:00 -0700 (PDT) From: SeongJae Park X-Google-Original-From: SeongJae Park To: Greg KH Cc: sj38.park@gmail.com, akpm@linux-foundation.org, SeongJae Park , Jonathan.Cameron@huawei.com, acme@kernel.org, alexander.shishkin@linux.intel.com, amit@kernel.org, benh@kernel.crashing.org, brendanhiggins@google.com, corbet@lwn.net, david@redhat.com, dwmw@amazon.com, elver@google.com, fan.du@intel.com, foersleo@amazon.de, gthelen@google.com, guoju.fgj@alibaba-inc.com, mgorman@suse.de, minchan@kernel.org, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, riel@surriel.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, shakeelb@google.com, shuah@kernel.org, snu@amazon.de, vbabka@suse.cz, vdavydov.dev@gmail.com, zgf574564920@gmail.com, linux-damon@amazon.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v26 07/13] mm/damon: Implement a debugfs-based user space interface Date: Tue, 30 Mar 2021 09:59:50 +0000 Message-Id: <20210330095950.33427-1-sjpark@amazon.de> X-Mailer: git-send-email 2.17.1 In-Reply-To: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C183D132 X-Stat-Signature: zcmc8yofo6x4n9wxip6yma5iceh54ao1 Received-SPF: none (gmail.com>: No applicable sender policy available) receiver=imf04; identity=mailfrom; envelope-from=""; helo=mail-qk1-f177.google.com; client-ip=209.85.222.177 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617098399-736609 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: SeongJae Park On Tue, 30 Mar 2021 11:22:45 +0200 Greg KH wrote: > On Tue, Mar 30, 2021 at 09:05:31AM +0000, sj38.park@gmail.com wrote: > > +static int __init __damon_dbgfs_init(void) > > +{ > > + struct dentry *dbgfs_root; > > + const char * const file_names[] = {"monitor_on"}; > > + const struct file_operations *fops[] = {&monitor_on_fops}; > > + int i; > > + > > + dbgfs_root = debugfs_create_dir("damon", NULL); > > + > > + for (i = 0; i < ARRAY_SIZE(file_names); i++) > > + debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL, > > + fops[i]); > > + dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]); > > + > > + dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL); > > No error checking for memory allocation failures? Oops, I will add the check in the next spin. > > > > + dbgfs_dirs[0] = dbgfs_root; > > + > > + return 0; > > +} > > + > > +/* > > + * Functions for the initialization > > + */ > > + > > +static int __init damon_dbgfs_init(void) > > +{ > > + int rc; > > + > > + dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL); > > No error checking? Will add in the next spin. > > > + dbgfs_ctxs[0] = dbgfs_new_ctx(); > > + if (!dbgfs_ctxs[0]) > > + return -ENOMEM; > > + dbgfs_nr_ctxs = 1; > > + > > + rc = __damon_dbgfs_init(); > > + if (rc) > > + pr_err("%s: dbgfs init failed\n", __func__); > > Shouldn't the error be printed out in the function that failed, not in > this one? I thought some other functions (in future) might want to use '__damon_dbgfs_init()' but siletnly handles it's failure. Therefore I made the function fails silently but returns the error code explicitly. Am I missing somthing? Thanks, SeongJae Park > > thanks, > > greg k-h