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Violators will be prosecuted for from ; Mon, 27 Aug 2018 13:52:38 +0100 Date: Mon, 27 Aug 2018 15:52:27 +0300 From: Mike Rapoport Subject: Re: [PATCH 2/2] clk: pmc-atom: use devm_kstrdup_const() References: <20180827082101.5036-1-brgl@bgdev.pl> <20180827082101.5036-2-brgl@bgdev.pl> <20180827103915.GC13848@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Message-Id: <20180827125226.GD13848@rapoport-lnx> Sender: owner-linux-mm@kvack.org List-ID: To: Bartosz Golaszewski Cc: Michael Turquette , Stephen Boyd , Greg Kroah-Hartman , "Rafael J . Wysocki" , Arend van Spriel , Ulf Hansson , Bjorn Helgaas , Vivek Gautam , Robin Murphy , Joe Perches , Heikki Krogerus , Andrew Morton , Michal Hocko , Al Viro , Jonathan Corbet , Roman Gushchin , Huang Ying , Kees Cook , Bjorn Andersson , linux-clk , Linux Kernel Mailing List , linux-mm@kvack.org On Mon, Aug 27, 2018 at 02:28:45PM +0200, Bartosz Golaszewski wrote: > 2018-08-27 12:39 GMT+02:00 Mike Rapoport : > > On Mon, Aug 27, 2018 at 10:21:01AM +0200, Bartosz Golaszewski wrote: > >> Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as > >> an example of how to use this new routine to shrink driver code. > >> > >> While we're at it: replace a call to kcalloc() with devm_kcalloc(). > >> > >> Signed-off-by: Bartosz Golaszewski > >> --- > >> drivers/clk/x86/clk-pmc-atom.c | 19 ++++--------------- > >> 1 file changed, 4 insertions(+), 15 deletions(-) > >> > >> diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c > >> index 08ef69945ffb..daa2192e6568 100644 > >> --- a/drivers/clk/x86/clk-pmc-atom.c > >> +++ b/drivers/clk/x86/clk-pmc-atom.c > >> @@ -253,14 +253,6 @@ static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data, > >> plt_clk_unregister_fixed_rate(data->parents[i]); > >> } > >> > >> -static void plt_clk_free_parent_names_loop(const char **parent_names, > >> - unsigned int i) > >> -{ > >> - while (i--) > >> - kfree_const(parent_names[i]); > >> - kfree(parent_names); > >> -} > >> - > >> static void plt_clk_unregister_loop(struct clk_plt_data *data, > >> unsigned int i) > >> { > >> @@ -286,8 +278,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev, > >> if (!data->parents) > >> return ERR_PTR(-ENOMEM); > >> > >> - parent_names = kcalloc(nparents, sizeof(*parent_names), > >> - GFP_KERNEL); > >> + parent_names = devm_kcalloc(&pdev->dev, nparents, > >> + sizeof(*parent_names), GFP_KERNEL); > >> if (!parent_names) > >> return ERR_PTR(-ENOMEM); > >> > >> @@ -300,7 +292,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev, > >> err = PTR_ERR(data->parents[i]); > >> goto err_unreg; > >> } > >> - parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL); > >> + parent_names[i] = devm_kstrdup_const(&pdev->dev, > >> + clks[i].name, GFP_KERNEL); > >> } > >> > >> data->nparents = nparents; > >> @@ -308,7 +301,6 @@ static const char **plt_clk_register_parents(struct platform_device *pdev, > >> > >> err_unreg: > >> plt_clk_unregister_fixed_rate_loop(data, i); > >> - plt_clk_free_parent_names_loop(parent_names, i); > > > > What happens if clks[i].name is not a part of RO data? The devm_kstrdup_const > > will allocate memory and nothing will ever free it... > > > > I'm looking at it and trying to see if I'm missing something, but > AFAIK the whole concept of devm_* is to leave out the resource > management part. > > devm_kstrdup_const() will internally call devm_kstrdup() for strings > that are not in .rodata and once the device is detached, the string > will be freed (or not if it's in .rodata). And when it's going to be freed, how the resource management will know whether it's .rodata or not? > BR > Bart > > > And, please don't drop kfree(parent_names) here. > > > >> return ERR_PTR(err); > >> } > >> > >> @@ -351,15 +343,12 @@ static int plt_clk_probe(struct platform_device *pdev) > >> goto err_unreg_clk_plt; > >> } > >> > >> - plt_clk_free_parent_names_loop(parent_names, data->nparents); > >> - > >> platform_set_drvdata(pdev, data); > >> return 0; > >> > >> err_unreg_clk_plt: > >> plt_clk_unregister_loop(data, i); > >> plt_clk_unregister_parents(data); > >> - plt_clk_free_parent_names_loop(parent_names, data->nparents); > > > > Ditto. > > > >> return err; > >> } > >> > >> -- > >> 2.18.0 > >> > > > > -- > > Sincerely yours, > > Mike. > > > -- Sincerely yours, Mike.