498d319bb5
This patch enhances the type safety for the kfifo API. It is now safe to put const data into a non const FIFO and the API will now generate a compiler warning when reading from the fifo where the destination address is pointing to a const variable. As a side effect the kfifo_put() does now expect the value of an element instead a pointer to the element. This was suggested Russell King. It make the handling of the kfifo_put easier since there is no need to create a helper variable for getting the address of a pointer or to pass integers of different sizes. IMHO the API break is okay, since there are currently only six users of kfifo_put(). The code is also cleaner by kicking out the "if (0)" expressions. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Hauke Mehrtens <hauke@hauke-m.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
124 lines
3.6 KiB
C
124 lines
3.6 KiB
C
/*
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* Copyright (C) 2013 Red Hat
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "drmP.h"
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#include "drm_flip_work.h"
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/**
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* drm_flip_work_queue - queue work
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* @work: the flip-work
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* @val: the value to queue
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*
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* Queues work, that will later be run (passed back to drm_flip_func_t
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* func) on a work queue after drm_flip_work_commit() is called.
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*/
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void drm_flip_work_queue(struct drm_flip_work *work, void *val)
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{
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if (kfifo_put(&work->fifo, val)) {
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atomic_inc(&work->pending);
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} else {
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DRM_ERROR("%s fifo full!\n", work->name);
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work->func(work, val);
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}
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}
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EXPORT_SYMBOL(drm_flip_work_queue);
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/**
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* drm_flip_work_commit - commit queued work
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* @work: the flip-work
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* @wq: the work-queue to run the queued work on
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*
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* Trigger work previously queued by drm_flip_work_queue() to run
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* on a workqueue. The typical usage would be to queue work (via
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* drm_flip_work_queue()) at any point (from vblank irq and/or
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* prior), and then from vblank irq commit the queued work.
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*/
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void drm_flip_work_commit(struct drm_flip_work *work,
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struct workqueue_struct *wq)
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{
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uint32_t pending = atomic_read(&work->pending);
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atomic_add(pending, &work->count);
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atomic_sub(pending, &work->pending);
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queue_work(wq, &work->worker);
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}
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EXPORT_SYMBOL(drm_flip_work_commit);
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static void flip_worker(struct work_struct *w)
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{
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struct drm_flip_work *work = container_of(w, struct drm_flip_work, worker);
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uint32_t count = atomic_read(&work->count);
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void *val = NULL;
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atomic_sub(count, &work->count);
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while(count--)
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if (!WARN_ON(!kfifo_get(&work->fifo, &val)))
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work->func(work, val);
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}
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/**
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* drm_flip_work_init - initialize flip-work
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* @work: the flip-work to initialize
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* @size: the max queue depth
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* @name: debug name
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* @func: the callback work function
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*
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* Initializes/allocates resources for the flip-work
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*
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* RETURNS:
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* Zero on success, error code on failure.
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*/
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int drm_flip_work_init(struct drm_flip_work *work, int size,
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const char *name, drm_flip_func_t func)
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{
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int ret;
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work->name = name;
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atomic_set(&work->count, 0);
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atomic_set(&work->pending, 0);
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work->func = func;
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ret = kfifo_alloc(&work->fifo, size, GFP_KERNEL);
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if (ret) {
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DRM_ERROR("could not allocate %s fifo\n", name);
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return ret;
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}
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INIT_WORK(&work->worker, flip_worker);
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return 0;
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}
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EXPORT_SYMBOL(drm_flip_work_init);
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/**
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* drm_flip_work_cleanup - cleans up flip-work
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* @work: the flip-work to cleanup
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*
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* Destroy resources allocated for the flip-work
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*/
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void drm_flip_work_cleanup(struct drm_flip_work *work)
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{
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WARN_ON(!kfifo_is_empty(&work->fifo));
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kfifo_free(&work->fifo);
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}
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EXPORT_SYMBOL(drm_flip_work_cleanup);
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