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. What about pulling the overflow-mul macro out of malloc_array() and doing this instead:
----------- >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;