| Message ID | 20180620143922.nkcazvbcrmkyvm2c@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 20 Jun 2018 16:39:22 +0200, Sebastian Andrzej Siewior wrote: > > On 2018-06-20 14:51:12 [+0200], Takashi Iwai wrote: > > On Tue, 19 Jun 2018 23:55:20 +0200, > > Sebastian Andrzej Siewior wrote: > > > - (*purb)->transfer_buffer = > > > - kmalloc_array(subs->maxpacksize, > > > - nr_of_packs(), GFP_KERNEL); > > > - if (NULL == (*purb)->transfer_buffer) { > > > + len = subs->maxpacksize * nr_of_packs(); > > > + buf = kmalloc(len, GFP_KERNEL); > > > > I'd keep kmalloc_array() as is, and just put subs->maxpacksize * > > nr_of_packs() in usb_fill_int_urb(). Otherwise it's a step backward. > > but then we end up with two multiplications. Yes, but it's no hot path, and the code won't bigger. And I bet you won't notice any performance lost by that :) > What about pulling the > overflow-mul macro out of malloc_array() and doing this instead: Well, it's neither smaller nor more readable... thanks, Takashi > > ----------- >8 > > Subject: [PATCH 8/9 v2] ALSA: usx2y: usbusx2yaudio: use usb_fill_int_urb() > > Using usb_fill_int_urb() helps to find code which initializes an > URB. A grep for members of the struct (like ->complete) reveal lots > of other things, too. > > The "&& !(*purb)->transfer_buffer" check has been removed because the > URB has been freshly allocated a few lines above so ->transfer_buffer > has to be NULL here. > The `dev' and `transfer_size' assignments have been moved from > usX2Y_urbs_start() to usX2Y_urbs_allocate() because they don't change > overtime. > The multiplication via check_mul_overflow() has been extracted from > kmalloc_array() to avoid two multiplication (one with overflow check and > one without for the length argument). This requires to change the type > `maxpacksize' to int so there is only one type involved in the > multiplication. > > Cc: Jaroslav Kysela <perex@perex.cz> > Cc: Takashi Iwai <tiwai@suse.com> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > sound/usb/usx2y/usbusx2y.h | 2 +- > sound/usb/usx2y/usbusx2yaudio.c | 38 ++++++++++++++++----------------- > 2 files changed, 20 insertions(+), 20 deletions(-) > > diff --git a/sound/usb/usx2y/usbusx2y.h b/sound/usb/usx2y/usbusx2y.h > index e0f77172ce8f..2bec412589b4 100644 > --- a/sound/usb/usx2y/usbusx2y.h > +++ b/sound/usb/usx2y/usbusx2y.h > @@ -56,7 +56,7 @@ struct snd_usX2Y_substream { > struct snd_pcm_substream *pcm_substream; > > int endpoint; > - unsigned int maxpacksize; /* max packet size in bytes */ > + int maxpacksize; /* max packet size in bytes */ > > atomic_t state; > #define state_STOPPED 0 > diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c > index 2b833054e3b0..e5580cb59858 100644 > --- a/sound/usb/usx2y/usbusx2yaudio.c > +++ b/sound/usb/usx2y/usbusx2yaudio.c > @@ -425,33 +425,35 @@ static int usX2Y_urbs_allocate(struct snd_usX2Y_substream *subs) > /* allocate and initialize data urbs */ > for (i = 0; i < NRURBS; i++) { > struct urb **purb = subs->urb + i; > + void *buf = NULL; > + int len = 0; > + > if (*purb) { > usb_kill_urb(*purb); > continue; > } > *purb = usb_alloc_urb(nr_of_packs(), GFP_KERNEL); > - if (NULL == *purb) { > - usX2Y_urbs_release(subs); > - return -ENOMEM; > - } > - if (!is_playback && !(*purb)->transfer_buffer) { > + if (NULL == *purb) > + goto err_free; > + > + if (!is_playback) { > /* allocate a capture buffer per urb */ > - (*purb)->transfer_buffer = > - kmalloc_array(subs->maxpacksize, > - nr_of_packs(), GFP_KERNEL); > - if (NULL == (*purb)->transfer_buffer) { > - usX2Y_urbs_release(subs); > - return -ENOMEM; > - } > + if (check_mul_overflow(subs->maxpacksize, > + nr_of_packs(), > + &len)) > + goto err_free; > + buf = kmalloc(len, GFP_KERNEL); > + if (!buf) > + goto err_free; > } > - (*purb)->dev = dev; > - (*purb)->pipe = pipe; > + usb_fill_int_urb(*purb, dev, pipe, buf, len, > + i_usX2Y_subs_startup, subs, 1); > (*purb)->number_of_packets = nr_of_packs(); > - (*purb)->context = subs; > - (*purb)->interval = 1; > - (*purb)->complete = i_usX2Y_subs_startup; > } > return 0; > +err_free: > + usX2Y_urbs_release(subs); > + return -ENOMEM; > } > > static void usX2Y_subs_startup(struct snd_usX2Y_substream *subs) > @@ -485,12 +487,10 @@ static int usX2Y_urbs_start(struct snd_usX2Y_substream *subs) > unsigned long pack; > if (0 == i) > atomic_set(&subs->state, state_STARTING3); > - urb->dev = usX2Y->dev; > for (pack = 0; pack < nr_of_packs(); pack++) { > urb->iso_frame_desc[pack].offset = subs->maxpacksize * pack; > urb->iso_frame_desc[pack].length = subs->maxpacksize; > } > - urb->transfer_buffer_length = subs->maxpacksize * nr_of_packs(); > if ((err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) { > snd_printk (KERN_ERR "cannot submit datapipe for urb %d, err = %d\n", i, err); > err = -EPIPE; > -- > 2.17.1 >
diff --git a/sound/usb/usx2y/usbusx2y.h b/sound/usb/usx2y/usbusx2y.h index e0f77172ce8f..2bec412589b4 100644 --- a/sound/usb/usx2y/usbusx2y.h +++ b/sound/usb/usx2y/usbusx2y.h @@ -56,7 +56,7 @@ struct snd_usX2Y_substream { struct snd_pcm_substream *pcm_substream; int endpoint; - unsigned int maxpacksize; /* max packet size in bytes */ + int maxpacksize; /* max packet size in bytes */ atomic_t state; #define state_STOPPED 0 diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c index 2b833054e3b0..e5580cb59858 100644 --- a/sound/usb/usx2y/usbusx2yaudio.c +++ b/sound/usb/usx2y/usbusx2yaudio.c @@ -425,33 +425,35 @@ static int usX2Y_urbs_allocate(struct snd_usX2Y_substream *subs) /* allocate and initialize data urbs */ for (i = 0; i < NRURBS; i++) { struct urb **purb = subs->urb + i; + void *buf = NULL; + int len = 0; + if (*purb) { usb_kill_urb(*purb); continue; } *purb = usb_alloc_urb(nr_of_packs(), GFP_KERNEL); - if (NULL == *purb) { - usX2Y_urbs_release(subs); - return -ENOMEM; - } - if (!is_playback && !(*purb)->transfer_buffer) { + if (NULL == *purb) + goto err_free; + + if (!is_playback) { /* allocate a capture buffer per urb */ - (*purb)->transfer_buffer = - kmalloc_array(subs->maxpacksize, - nr_of_packs(), GFP_KERNEL); - if (NULL == (*purb)->transfer_buffer) { - usX2Y_urbs_release(subs); - return -ENOMEM; - } + if (check_mul_overflow(subs->maxpacksize, + nr_of_packs(), + &len)) + goto err_free; + buf = kmalloc(len, GFP_KERNEL); + if (!buf) + goto err_free; } - (*purb)->dev = dev; - (*purb)->pipe = pipe; + usb_fill_int_urb(*purb, dev, pipe, buf, len, + i_usX2Y_subs_startup, subs, 1); (*purb)->number_of_packets = nr_of_packs(); - (*purb)->context = subs; - (*purb)->interval = 1; - (*purb)->complete = i_usX2Y_subs_startup; } return 0; +err_free: + usX2Y_urbs_release(subs); + return -ENOMEM; } static void usX2Y_subs_startup(struct snd_usX2Y_substream *subs) @@ -485,12 +487,10 @@ static int usX2Y_urbs_start(struct snd_usX2Y_substream *subs) unsigned long pack; if (0 == i) atomic_set(&subs->state, state_STARTING3); - urb->dev = usX2Y->dev; for (pack = 0; pack < nr_of_packs(); pack++) { urb->iso_frame_desc[pack].offset = subs->maxpacksize * pack; urb->iso_frame_desc[pack].length = subs->maxpacksize; } - urb->transfer_buffer_length = subs->maxpacksize * nr_of_packs(); if ((err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) { snd_printk (KERN_ERR "cannot submit datapipe for urb %d, err = %d\n", i, err); err = -EPIPE;