![Gabriele Mazzotta](/assets/img/avatar_default.png)
Check whether the allocation of a new kfifo buffer failed or not before setting the update_needed flag to false. This will make iio_request_update_kfifo() try to allocate a new buffer the next time a buffer update is requested. Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
220 lines
4.7 KiB
C
220 lines
4.7 KiB
C
#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/workqueue.h>
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#include <linux/kfifo.h>
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#include <linux/mutex.h>
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#include <linux/iio/kfifo_buf.h>
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#include <linux/sched.h>
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#include <linux/poll.h>
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struct iio_kfifo {
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struct iio_buffer buffer;
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struct kfifo kf;
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struct mutex user_lock;
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int update_needed;
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};
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#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
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static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
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int bytes_per_datum, int length)
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{
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if ((length == 0) || (bytes_per_datum == 0))
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return -EINVAL;
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return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
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bytes_per_datum, GFP_KERNEL);
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}
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static int iio_request_update_kfifo(struct iio_buffer *r)
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{
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int ret = 0;
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struct iio_kfifo *buf = iio_to_kfifo(r);
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mutex_lock(&buf->user_lock);
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if (buf->update_needed) {
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kfifo_free(&buf->kf);
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ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
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buf->buffer.length);
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if (ret >= 0)
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buf->update_needed = false;
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} else {
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kfifo_reset_out(&buf->kf);
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}
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mutex_unlock(&buf->user_lock);
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return ret;
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}
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static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
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{
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struct iio_kfifo *kf = iio_to_kfifo(r);
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kf->update_needed = true;
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return 0;
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}
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static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
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{
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if (r->bytes_per_datum != bpd) {
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r->bytes_per_datum = bpd;
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iio_mark_update_needed_kfifo(r);
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}
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return 0;
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}
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static int iio_set_length_kfifo(struct iio_buffer *r, int length)
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{
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/* Avoid an invalid state */
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if (length < 2)
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length = 2;
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if (r->length != length) {
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r->length = length;
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iio_mark_update_needed_kfifo(r);
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}
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return 0;
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}
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static int iio_store_to_kfifo(struct iio_buffer *r,
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const void *data)
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{
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int ret;
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struct iio_kfifo *kf = iio_to_kfifo(r);
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ret = kfifo_in(&kf->kf, data, 1);
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if (ret != 1)
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return -EBUSY;
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return 0;
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}
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static int iio_read_first_n_kfifo(struct iio_buffer *r,
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size_t n, char __user *buf)
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{
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int ret, copied;
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struct iio_kfifo *kf = iio_to_kfifo(r);
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if (mutex_lock_interruptible(&kf->user_lock))
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return -ERESTARTSYS;
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if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
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ret = -EINVAL;
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else
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ret = kfifo_to_user(&kf->kf, buf, n, &copied);
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mutex_unlock(&kf->user_lock);
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if (ret < 0)
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return ret;
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return copied;
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}
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static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
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{
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struct iio_kfifo *kf = iio_to_kfifo(r);
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size_t samples;
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mutex_lock(&kf->user_lock);
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samples = kfifo_len(&kf->kf);
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mutex_unlock(&kf->user_lock);
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return samples;
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}
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static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
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{
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struct iio_kfifo *kf = iio_to_kfifo(buffer);
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mutex_destroy(&kf->user_lock);
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kfifo_free(&kf->kf);
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kfree(kf);
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}
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static const struct iio_buffer_access_funcs kfifo_access_funcs = {
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.store_to = &iio_store_to_kfifo,
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.read_first_n = &iio_read_first_n_kfifo,
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.data_available = iio_kfifo_buf_data_available,
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.request_update = &iio_request_update_kfifo,
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.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
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.set_length = &iio_set_length_kfifo,
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.release = &iio_kfifo_buffer_release,
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};
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struct iio_buffer *iio_kfifo_allocate(void)
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{
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struct iio_kfifo *kf;
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kf = kzalloc(sizeof(*kf), GFP_KERNEL);
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if (!kf)
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return NULL;
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kf->update_needed = true;
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iio_buffer_init(&kf->buffer);
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kf->buffer.access = &kfifo_access_funcs;
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kf->buffer.length = 2;
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mutex_init(&kf->user_lock);
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return &kf->buffer;
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}
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EXPORT_SYMBOL(iio_kfifo_allocate);
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void iio_kfifo_free(struct iio_buffer *r)
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{
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iio_buffer_put(r);
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}
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EXPORT_SYMBOL(iio_kfifo_free);
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static void devm_iio_kfifo_release(struct device *dev, void *res)
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{
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iio_kfifo_free(*(struct iio_buffer **)res);
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}
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static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
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{
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struct iio_buffer **r = res;
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if (WARN_ON(!r || !*r))
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return 0;
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return *r == data;
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}
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/**
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* devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
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* @dev: Device to allocate kfifo buffer for
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*
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* RETURNS:
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* Pointer to allocated iio_buffer on success, NULL on failure.
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*/
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struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
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{
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struct iio_buffer **ptr, *r;
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ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
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if (!ptr)
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return NULL;
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r = iio_kfifo_allocate();
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if (r) {
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*ptr = r;
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devres_add(dev, ptr);
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} else {
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devres_free(ptr);
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}
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return r;
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}
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EXPORT_SYMBOL(devm_iio_kfifo_allocate);
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/**
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* devm_iio_fifo_free - Resource-managed iio_kfifo_free()
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* @dev: Device the buffer belongs to
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* @r: The buffer associated with the device
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*/
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void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
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{
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WARN_ON(devres_release(dev, devm_iio_kfifo_release,
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devm_iio_kfifo_match, r));
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}
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EXPORT_SYMBOL(devm_iio_kfifo_free);
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MODULE_LICENSE("GPL");
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