From: Jonathan Cameron Date: Sat, 30 Jun 2012 12:52:00 +0000 (+0100) Subject: iio:kfifo_buf Take advantage of the fixed record size used in IIO X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c559afbfb08c7eac215ba417251225d3a8e01062;p=deliverable%2Flinux.git iio:kfifo_buf Take advantage of the fixed record size used in IIO By bypassing the standard macros for setting up the kfifo we can take advantage of the fixed record size implementation without having to have a type to pass in (from which the size of an element is normally established). In IIO we have variable 'scans' as our records in which any element can be present or not. They do not however vary when we are actually filling or reading from the buffer. Thus we have a fixed record size whenever we are actually running. As setup and tear down are not in the fast path we can take the overhead of reinitializing the kfifo every time. Signed-off-by: Jonathan Cameron Tested-by: Lars-Peter Clausen --- diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c index 6bf9d05f4841..8a6d28ce21b2 100644 --- a/drivers/iio/kfifo_buf.c +++ b/drivers/iio/kfifo_buf.c @@ -22,7 +22,8 @@ static inline int __iio_allocate_kfifo(struct iio_kfifo *buf, return -EINVAL; __iio_update_buffer(&buf->buffer, bytes_per_datum, length); - return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL); + return __kfifo_alloc((struct __kfifo *)&buf->kf, length, + bytes_per_datum, GFP_KERNEL); } static int iio_request_update_kfifo(struct iio_buffer *r) @@ -94,9 +95,10 @@ static int iio_store_to_kfifo(struct iio_buffer *r, { int ret; struct iio_kfifo *kf = iio_to_kfifo(r); - ret = kfifo_in(&kf->kf, data, r->bytes_per_datum); - if (ret != r->bytes_per_datum) + ret = kfifo_in(&kf->kf, data, 1); + if (ret != 1) return -EBUSY; + return 0; } @@ -109,7 +111,6 @@ static int iio_read_first_n_kfifo(struct iio_buffer *r, if (n < r->bytes_per_datum) return -EINVAL; - n = rounddown(n, r->bytes_per_datum); ret = kfifo_to_user(&kf->kf, buf, n, &copied); return copied;