From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755973AbcAMSZy (ORCPT ); Wed, 13 Jan 2016 13:25:54 -0500 Received: from mail-wm0-f44.google.com ([74.125.82.44]:36342 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752072AbcAMSZw (ORCPT ); Wed, 13 Jan 2016 13:25:52 -0500 Subject: Re: [PATCHv2 1/2] usb: gadget: f_midi: use flexible array member for gmidi_in_port elements To: Michal Nazarewicz , Felipe Balbi , Greg Kroah-Hartman , Dan Carpenter References: <1452311230-21431-1-git-send-email-mina86@mina86.com> Cc: Robert Baldyga , Andrzej Pietrasiewicz , Pawel Szewczyk , linux-kernel@vger.kernel.org From: Felipe Ferreri Tonello X-Enigmail-Draft-Status: N1111 Message-ID: <569696CE.1000707@felipetonello.com> Date: Wed, 13 Jan 2016 18:26:22 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <1452311230-21431-1-git-send-email-mina86@mina86.com> Content-Type: multipart/mixed; boundary="------------040208040003020905040708" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------040208040003020905040708 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Hi Michael, On 09/01/16 03:47, Michal Nazarewicz wrote: > Reduce number of allocations, simplify memory management and reduce > memory usage by stacking the gmidi_in_port elements at the end of the > f_midi structure using a flexible array. > > Also, observe that gmidi_in_port::midi pointer is *never* used for any > purpose so it can be safely removed. > > Signed-off-by: Michal Nazarewicz > --- > drivers/usb/gadget/function/f_midi.c | 43 ++++++++++++------------------------ > 1 file changed, 14 insertions(+), 29 deletions(-) > > On Tue, Jan 05 2016, Dan Carpenter wrote: >> On Tue, Jan 05, 2016 at 02:55:31PM +0100, Michal Nazarewicz wrote: >>> @@ -568,12 +568,12 @@ static int f_midi_in_open(struct snd_rawmidi_substream *substream) >>> { >>> struct f_midi *midi = substream->rmidi->private_data; >>> >>> - if (!midi->in_port[substream->number]) >>> + if (substream->number > midi->in_ports) >> >> This is off by one. It should be >= midi->in_ports. > > Fixed. > > Since there were no objections to this small patch set (i.e. there was > mostly silence about it), I’ll go ahead and interpret it as ‘go ahead > and properly submit it’. :) > > diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c > index 898a570..fd67af2 100644 > --- a/drivers/usb/gadget/function/f_midi.c > +++ b/drivers/usb/gadget/function/f_midi.c > @@ -55,7 +55,6 @@ static const char f_midi_longname[] = "MIDI Gadget"; > * USB <- IN endpoint <- rawmidi > */ > struct gmidi_in_port { > - struct f_midi *midi; This change is unrelated. I sent a patch removing this pointer as well. > int active; > uint8_t cable; > uint8_t state; > @@ -78,7 +77,6 @@ struct f_midi { > > struct snd_rawmidi_substream *in_substream[MAX_PORTS]; > struct snd_rawmidi_substream *out_substream[MAX_PORTS]; > - struct gmidi_in_port *in_port[MAX_PORTS]; > > unsigned long out_triggered; > struct tasklet_struct tasklet; > @@ -87,6 +85,8 @@ struct f_midi { > int index; > char *id; > unsigned int buflen, qlen; > + > + struct gmidi_in_port in_ports_array[/* in_ports */]; > }; > > static inline struct f_midi *func_to_midi(struct usb_function *f) > @@ -529,11 +529,11 @@ static void f_midi_transmit(struct f_midi *midi, struct usb_request *req) > req->length = 0; > req->complete = f_midi_complete; > > - for (i = 0; i < MAX_PORTS; i++) { > - struct gmidi_in_port *port = midi->in_port[i]; > + for (i = 0; i < midi->in_ports; i++) { > + struct gmidi_in_port *port = midi->in_ports_array + i; > struct snd_rawmidi_substream *substream = midi->in_substream[i]; > > - if (!port || !port->active || !substream) > + if (!port->active || !substream) > continue; > > while (req->length + 3 < midi->buflen) { > @@ -568,12 +568,12 @@ static int f_midi_in_open(struct snd_rawmidi_substream *substream) > { > struct f_midi *midi = substream->rmidi->private_data; > > - if (!midi->in_port[substream->number]) > + if (substream->number >= midi->in_ports) > return -EINVAL; > > VDBG(midi, "%s()\n", __func__); > midi->in_substream[substream->number] = substream; > - midi->in_port[substream->number]->state = STATE_UNKNOWN; > + midi->in_ports_array[substream->number].state = STATE_UNKNOWN; > return 0; > } > > @@ -589,11 +589,11 @@ static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up) > { > struct f_midi *midi = substream->rmidi->private_data; > > - if (!midi->in_port[substream->number]) > + if (substream->number >= midi->in_ports) > return; > > VDBG(midi, "%s() %d\n", __func__, up); > - midi->in_port[substream->number]->active = up; > + midi->in_ports_array[substream->number].active = up; > if (up) > tasklet_hi_schedule(&midi->tasklet); > } > @@ -1067,14 +1067,11 @@ static void f_midi_free(struct usb_function *f) > { > struct f_midi *midi; > struct f_midi_opts *opts; > - int i; > > midi = func_to_midi(f); > opts = container_of(f->fi, struct f_midi_opts, func_inst); > kfree(midi->id); > mutex_lock(&opts->lock); > - for (i = opts->in_ports - 1; i >= 0; --i) > - kfree(midi->in_port[i]); > kfree(midi); > --opts->refcnt; > mutex_unlock(&opts->lock); > @@ -1115,26 +1112,16 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi) > } > > /* allocate and initialize one new instance */ > - midi = kzalloc(sizeof(*midi), GFP_KERNEL); > + midi = kzalloc( > + sizeof(*midi) + opts->in_ports * sizeof(*midi->in_ports_array), > + GFP_KERNEL); Is there a garantee that the compiler will always use in_ports_array at the end of the allocated block? > if (!midi) { > mutex_unlock(&opts->lock); > return ERR_PTR(-ENOMEM); > } > > - for (i = 0; i < opts->in_ports; i++) { > - struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL); > - > - if (!port) { > - status = -ENOMEM; > - mutex_unlock(&opts->lock); > - goto setup_fail; > - } > - > - port->midi = midi; > - port->active = 0; > - port->cable = i; > - midi->in_port[i] = port; > - } > + for (i = 0; i < opts->in_ports; i++) > + midi->in_ports_array[i].cable = i; > > /* set up ALSA midi devices */ > midi->id = kstrdup(opts->id, GFP_KERNEL); > @@ -1161,8 +1148,6 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi) > return &midi->func; > > setup_fail: > - for (--i; i >= 0; i--) > - kfree(midi->in_port[i]); > kfree(midi); > return ERR_PTR(status); > } > Felipe --------------040208040003020905040708 Content-Type: application/pgp-keys; name="0x92698E6A.asc" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="0x92698E6A.asc" -----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG v2 mQINBFYedIcBEACVKGKoEjb3zlvAz5SUvBej7Sx13BPd8hVulQD+mqjfuRFPmZA5 LBXPX1zTRWwGEbbZegP3tLfKP+XekzO6BQhDihMmKuRusdgDsdMtldwhjHuUwKn7 kxB2k79jSG802lAjIv2l5hijOfKIGTATKwiMijuXho54DGltIgNyN/Onwk9HnM6d jsV5uubaI468JRH6j8HXXievo24BDvsimIE75ImiM53ruiwPwEry1hi1CnE5OpqG oe/lt27+nLXijfNZOpBZ3Q+RPVBdqPTkMlBJAa4sg+qwZoSMvQJFAGROiJ7+ICCW O4GPMrAn8CRcCI9ENKBj2dQ4bBEP1a+f16GNMUUU37wocqtyNHo0Pa/DnFh91kcu /2dvUX4XPeEimEoSKroRLOXC9RGSFYB/r9UXqFgbmyQ4TZLx0mAWIjoUQtbIJNRz Pt46UeznCVLJTg7CzIvtv8vwmMFvaepr8ONoZn+tpX8VW4dgzsMZDrVspE0Vg3oo K9JRi1nN3GcJJK4zG2ShvEkPffRHuBuyX5wR8MPRYTShKnJR5qd1cCSK73fCv4DP bjywmGjucqcLiyYbByjmHaqzRaKJclmT/jhs6qZHs+pVLkmHkHdf/WLP6Xgcvmo8 c+SATrJwRsyW9riyMB7uNg3T84umbQrl00nAhcq73rem/602H+Qrh8rEfQARAQAB tC1GZWxpcGUgRmVycmVyaSBUb25lbGxvIDxldUBmZWxpcGV0b25lbGxvLmNvbT6J AjwEEwEIACYCGyMHCwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAIZAQUCVlXsdwAK CRDMRLTQkmmOapJFD/9XZZdX5XdXrQ2Qr7znQCOMPfOFiTqK8A1vVJPfLcPdkDyW iDfV2w4jyxKjgkcO8hgjZWAGdXhKxEXt8bQIZ+Po3eOqKo/O69+WyYS33uAKfNbr t4BcJOM2Vh2MwTymzh5EKjsKi/vmqFqvcpa81Jc4exDaHhb2mqMW8DZc96nMPwij +Z4vVooOVt5DVGeG4o2rztoti+KaXys6nycm8ErMmqWmL0viEnXHDRTOUHpnhEQY Vlg+hfxYrk00DphAePrpRp/HaxNncxR+ID0SHmYlLCaEy7s5ksOORjlKSk+7Nqat X69ymfXeEI84ror11IR7kuAA+rkhHMacWXANPkXtuEBi9Nl3V5Rvud4f/RL3Sh2x lwPfxca9rIR/7JYwoCzQ8iORok3VqKOtpufLKMsIl9sdj7ZxI6f6tZDm5uAaCZAt f15EcGiVWZgGdKlXzIWFkUsdRhtGYEQBF1Li/qLrnoS5T32eSCt8cgJlkDyKqNbX fxvV0KON8tJ9jBnMmoADetF/9V3A6EIBtTdxsz+UKjk6PV0bx398AbdvNB22r6Kw n1E2ZqzfNIaAOv5lEHh7VP7+s3vdXcKfnfobW0qd56NpAGTPhAN00wl7T5oMN3xS MNTPIC4316E8KChA5CQ3h6RRlZYvAJx7QWfJKX5zb8EVcJb0ul67V8hn1h/s54kC PwQTAQgAKQUCVh50hwIbIwUJCWYBgAcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheA AAoJEMxEtNCSaY5qHxAP/0LmkXtaZvFelixfYibDHwpz+62mWydYN8I13ikV7uK0 DxpN6W3SeoAY6mF6mwHKyhsNhlOYPR8Rb+CpJxjIez6sPHAA02m4HqfTiNRuAeLM hSpiMIVesGgR9Lt/2gnCcF/R/pNJd5RC7wWzeeiS9/b2XtFImRSFvctyHwGXLBYM nlRx/o34kWscTCqixBF7lm3umAErDUd0fvL4oV2sC3W8Ncjfk/WQWfschV50lNtO h1Imvt+5ud3AJEcwXew0pbHKHvtrVc7toIO3jhZypD9YXP3aR9ZEkHS/bnd5HRHV t3iEwXH+bNu/evEB5dQcSf6M6Bwt7Ty2fqFx2PUmnZ22W4HGelPmE5aCqkBQqAkR kBmPEPlUIz6GLoj8jUL1ey+T+oCyD5wZoVb841bJDKIPxAa+P+MjFtQUpSXgyi8x G0Ic10pK9u3xsu5xzqLoAwt+pK+oxeWrZhJXg9/MFmqQQTX2dH8lIrgIOsHis5uK ySohiPwYQ0HUbbSFB9wM6e5dq621RvOkMA/myFtdjJX+Ynr7FmIpIZQiWZvOv0nM 0CeF7MotMIVa1ioh9K6/Z5WLjTBQh32DrGL07H0h+SMOvcL1IJuw9aG5qDKH4VW9 VSbHAogVSntamVrCg8jcT8uxEtwZNZH3aBqoYv4pa4MJsIs6vI0/9Y/mVyYVhQPN tDFGZWxpcGUgRmVycmVyaSBUb25lbGxvIDxmZWxpcGUudG9uZWxsb0BnbWFpbC5j b20+iQI5BBMBCAAjAhsjBwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AFAlZV7HoA CgkQzES00JJpjmqexA//UHC0P+5NMN0HS0EC3vqdf+9AFfX/Gx+q6BjlaYh8gkGI 5SNGGb25dooGBRhXzFvp5UmxQjngvZO0Jl071kbqOs7IylZWvUB0tIB/9kcvIgJM U13CvdD2XwHDgKoCCS07ymFd9j31FhfYK6eRpr72oGHtjhGOSIj1u8T/4mJDstoc zK39gZjTQjzT/2sDbr2sd41KLJ9Ly3H67EgoxYIAQQwwT1Z7x88a8BORIXS8iZPw z3D8A1r2BT55qukwEP7GktNArKlhrieFRHCxk8PAtZRj8TrOEyG9nnuZWZQWcb6M suIY6s4cyL5KRTUgGfnpc+VMcNKnm0WmKg5jZXRFwg0DECZi0wJqsS8GPrq4La+K laxPcXj3ShJePj0YuTcJ/fPYoqqelcbmlqg6m+S9s8PRKPzlESt2jYPbgqMzE0Lu DLRGT7SBYgHgDVFwIuFyHQaqEhnU/nLWmyMSuTOE5L4s/CR1xY4qQUtOTnDFbwqL 125kbOCiRSMBBMOB4Q+UW3+dJ7uqo6LSqIKa/LWvzRmn5po4iSHAD18ivOh1wTe6 0d/ngjzpTm80uFrwfgkQTexxESYjlBbceBC8kpb1zPFrip41hIi3iPP9UQnnpOO2 hDrQu5z0N8HMIFg3kciR22wUMzQnyVN4iKfkrhERjjuYWOXJmC5I76DBqlEKLCWJ Aj8EEwEIACkFAlYyWW0CGyMFCQlmAYAHCwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIX gAAKCRDMRLTQkmmOakxGD/4xoYnRMuy8m6IwT1Y6mWzXZMkcClxwisUkwgF37jMR Xk7aitPqlD7AOn/jzKZBmKqOokyH3Y65u/AV6O7jXWWM3Ru0fDYYt0RZR0CkE0c2 Rio64ol6GWnF4dIiyTTSyxBNadVJXRYBpp5G78ie495ZOp35WUoz2RhExeIQGkBb ++UIyCh3eK70PPJ+1/dDV9sSRncIBZLSv+4hc4gS6YoprtSgiS8sdf8uBVtjT3r0 nmrKfTpktADqOOACd/K3LIdf6rlvAYsuWdQ/q32MF7Clrlpt9e5oqi+ASJcLNWUz cT8nFyvjJzM5kQEBblT6uzyWE5N6+K/t23Uw13vSx3Z2uhhfRQjcSOcZgHdvc8w1 3UXhE+XRCMmtA7jonJuFLYOXbjeeNEbJj5ManrOQMSnVy+kRlf3pLoc7VjJGd2k9 w1U+62b1IVypQCoDNhIy3YTjw7D151z/i5tK5yBvntswji10InowqPRuvt3C3fpW kv2MnB6qI+u6M5bP/1CvkLSC9vX+gavUFYZ/wCESVrl1FYQPfOoEgvEId9Ajzx0B qyR/5jXY3ZzWhnXNtYpHXy5/mJdvZ+v5ra5JLWKVA3pa+QbTd3v6ELo9NKavylcD FX9X2l2s7kp/FRVUZg3mr/3Pf0R1EFZAwM2Fgb5iKPLPjGi4b4sVtMxeXfbXRMBf 5rQwRmVsaXBlIEZlcnJlcmkgVG9uZWxsbyA8ZmVsaXBlLnRvbmVsbG9Acm9saS5j b20+iQI5BBMBCAAjAhsjBwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AFAlZV7HoA CgkQzES00JJpjmrkTA//YiyBcGn+hjsKsVxFHseUw0ygN7TDLGeG7z0sP7AybVXR h4AwVcqyNkJjJ1UPXxPm5ra6/TbJf3XEalhIJtqh0MI0p+NQTFVOcGG58e6oMWj1 yBHAPmCyMJCi3GrB1/weP3qMiCdKWOWjxt+NoWss3pqqpSKHGW2rgmM3VP60iheR uZDDDI9DtoDz1ePT2AQZnopez2k75syZix1zkAI/VM/T3Y5lcnbaO4C+akDusfN0 galjwveYPIv6bBY6gd3B/7leSe2l4M3VIahj/1e4R2aLB78/pyy5BaI47zprkzPF zOAtZTurrwnE/1s3qWMP3OFeKiD1NLCm8kkvVakk/FjG8avFTAB3idNjpRT3wyPp nGv3G5Bp2jII35l7L5e2/zGcIigDNAUtdL3IgszfqtTVwGgISZDoxHIyBucqpYqV +ZesP1CpvyXaG4ME1QNTYZcVj1VTtz97IwntHw51r0d4IXjTbbrwJYR/g15XqNRB HwQyumPr3kMXLKTHCroK0z1OoT+pwNAO/XEWqQ5NQwyjalkFa1PzSPgcbTH46gs+ lilkrSgDuj/Amt0pkBSadgviJhsq2nQU49E8OOrrgDab0Z+6ur2lTENPWD4U9PS1 PisVd3ZAm8WmLx1ZktMgv2IPS9Tm+HlIdTPcw8OY12iPP1tRcE7pu23HLP3Un++0 KEZlbGlwZSBGZXJyZXJpIFRvbmVsbG8gPGZlbGlwZUByb2xpLmNvbT6JAjkEEwEI ACMCGyMHCwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAUCVlXsegAKCRDMRLTQkmmO aoymD/94mkk+RCXUQI6i3Z5qfenWHaJF86SH1tekpJl3eFHEUji0JWICOWS9225E 3oBbLDAA3szFWFxXNA2JdOv0ljwqWHT/aRXJlQ19LHMItguUyxfoELf818aym8bL MtazXRrYTy71SfvJwIleMYrNeodZnC4GwSOaKz5Rh/Qbnfzz/wG4dCNtGTcQ+EKP vcA06bNbYaqGA+qtrZ3st3lEmz/OPqRox7LqZTs/fvdAo49F8BlTZ6p09s2u7wVF UfYbi4+PQonGpn47QTx41OjFzzeA3NnCDak6JuSYa92QznShP0b03G5g4LdonwbU P/ivpzkSdWYVNwp/a7GfuhBAyk2VP/StF6WzzGC0j4TyBx+H5RzU32brNNsye1bL 8AMvHl9C3BEdgLnIlsTRMRCjs7f4EoFyEzmW40FUXPaJzxF6bCY/+GzDIhtMisjK fUFyakHnjITZSjo7Wqhp3W6a64esqPFbuFoX7sp5mWYzqDuKy0yD7S9vjA8wLdCt usBRw6TvVhaxmnOOa8zkyhOLqJ6le+zw8mW+Cot4LFFkeXyySNyRbrqOx3JqezRc olouAh2AJEir2sW3kdP53xRwUE5CJogC2QPuGSl5T1pcARmQJmudco2dk7C+hriF hkCHjp5ue9evv6u/Z7m+AcPJguVlq21ynYRrTeFJXCd2rgkAWbkCDQRWHnSHARAA yrLAhPO4JiqRk2sem+8bweimfnKmIm+ttTqjDni1DdBKtCZFUxPwEKzuOpU4aals 9Ohk4rQMnm6Q2XaJxIs0lijQJjVFbExtm9G2R2gkPJ5fnk4+k2mvps5F/iJjQk0k zWMITEA6cJzt9B8YC4dfsIq3lhCInOvSMBIVtDapruDGU4OskFBiKfzIq8diq/Ep qNfwCxZX2IcPhFv2+SJjph60oUC4WJ4zgINfJWdUGlIZrQp8sr/aEa77BVtLnTsu MHwqOF7P7yk4qpb3EFuyNCsJVAirYTqZeMWEv/pYiwtAgYOewdwptP8+5lbcXAor Y8Cs0GdW0r7LUzQjfhXl67EQWJuvGDBKMQ35LyUJtOm5m+qAnalz9Eyb0xRc9Arl rzH2GfCIr4ga+2RPw7fq7fZcbBcJDs770Mz0kVrLv3IAcc6fmnvuo30TFeIPB62/ c4xIe8njJ8RxbfwYAtd2KoAzwRQEqJQECyNnqENFHj2cimEueXf7NAw+z1nl1HIl 7MrHUeA0FQTw4WdGCahTuFRaJCjmODmKCFAooDWEek6jwNv18hCDJytSDc7uLAvH D2b9Sd40P1V2ochSf/DS/osfEIEeBf5mkG/MHBBbNxvSGP1h2yUM5C7g4nc6B+nz 5bIULhw0ojZx+U1i63gJkMsVMjKDAa+mGsWu0vAI3v0AEQEAAYkCHwQYAQgACQIb DAUCVlXsegAKCRDMRLTQkmmOao4vD/9GYLw5VmydK5BJ0sX12QmR7oMK4skMkcg/ gofkJ6njI4ETDG/pQfgBSQ/P0gUMXmhHgmpaRgs0tkS2NwsvURianXiQNpJwUA2g qKngqWlEvGOVkgOw7JKpdLWBvEW4vfP0Z0Q9brdeQG//9T9xyoyTC/jPM9A33NtI KlexBfBT7lXBy/y4tqf96KTOXk3STmI6nmSwmpPPtjxXXGQiMExGxAru+VX0HFxi JBS2fw/ucluVk2kffAO0y7DTL0UH3IWq4wEtHJQlEcujmUkP8PJSVIkhJpNlppR2 97DVxLcMAbnyxCW+ms1lCuZ5KB98KtowipqY9jhAPeP06W2WikENdmpLfNHhyIaM NKF7J+4zqPda7jZN1aKqs5OguJ4V82xXRJ0O6qSAd3Kvwi3MaKtNAv09JFG7UIcK ALJ+OQBzc00z54ii19ZPHjER6cYmcVutBUGOssqtyCOZymVbc7VYecdjxVrLwdDp LHHpcIjFn5ADjIAwGlt5ttkPvFTmqLeSWG9+vtoBShzQdeKJ4AN4r6/for/XsmF4 Jf7qGK8RamVX8lpWaNjUGtVSUOMTaSR1pmQJERDO2/WEZCm5hUFkYDbu+h+9m1W+ KL2ZkyGRC8FoZ46ly1J8koEeEoa57Au/uyK3KyvzlXuCI5zgGE+TohIjOr6d3TN4 SkAyCfQaSw=3D=3D =3DJwBB -----END PGP PUBLIC KEY BLOCK----- --------------040208040003020905040708--