On 2018-06-20 16:52:45 [+0200], Takashi Iwai wrote: > > 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...
okay, as you wish: > thanks, > > Takashi ----------- >8 Subject: [PATCH 8/9 v3] 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 <[email protected]> Cc: Takashi Iwai <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- sound/usb/usx2y/usbusx2yaudio.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c index 2b833054e3b0..ee8d21a784fd 100644 --- a/sound/usb/usx2y/usbusx2yaudio.c +++ b/sound/usb/usx2y/usbusx2yaudio.c @@ -425,6 +425,9 @@ 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; @@ -434,22 +437,20 @@ static int usX2Y_urbs_allocate(struct snd_usX2Y_substream *subs) usX2Y_urbs_release(subs); return -ENOMEM; } - if (!is_playback && !(*purb)->transfer_buffer) { + + 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) { + buf = kmalloc_array(subs->maxpacksize, nr_of_packs, + GFP_KERNEL); + if (!buf) { usX2Y_urbs_release(subs); return -ENOMEM; } + len = subs->maxpacksize * nr_of_packs; } - (*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; } @@ -485,12 +486,10 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
