diff options
Diffstat (limited to 'recipes-kernel/linux/linux-yocto/generic-drivers/0001-FROMLIST-dma-heap-Add-proper-kref-handling-on-dma-bu.patch')
| -rw-r--r-- | recipes-kernel/linux/linux-yocto/generic-drivers/0001-FROMLIST-dma-heap-Add-proper-kref-handling-on-dma-bu.patch | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-yocto/generic-drivers/0001-FROMLIST-dma-heap-Add-proper-kref-handling-on-dma-bu.patch b/recipes-kernel/linux/linux-yocto/generic-drivers/0001-FROMLIST-dma-heap-Add-proper-kref-handling-on-dma-bu.patch new file mode 100644 index 0000000..87fefa9 --- /dev/null +++ b/recipes-kernel/linux/linux-yocto/generic-drivers/0001-FROMLIST-dma-heap-Add-proper-kref-handling-on-dma-bu.patch @@ -0,0 +1,145 @@ +From dd2c03120004f3bfed8b4f6500c33957b1bae807 Mon Sep 17 00:00:00 2001 +From: John Stultz <jstultz@google.com> +Date: Mon, 11 Sep 2023 10:30:31 +0800 +Subject: [PATCH 1/2] FROMLIST: dma-heap: Add proper kref handling on dma-buf + heaps + +Add proper refcounting on the dma_heap structure. +While existing heaps are built-in, we may eventually +have heaps loaded from modules, and we'll need to be +able to properly handle the references to the heaps + +Also moves minor tracking into the heap structure so +we can properly free things. + +[Yong: Just add comment for "minor" and "refcount"] +Signed-off-by: John Stultz <jstultz@google.com> +Signed-off-by: T.J. Mercier <tjmercier@google.com> +Signed-off-by: Yong Wu <yong.wu@mediatek.com> +Signed-off-by: Vijayanand Jitta <quic_vjitta@quicinc.com> +Signed-off-by: Atul Dhudase <quic_adhudase@quicinc.com> +Upstream-Status: Submitted [https://lore.kernel.org/lkml/20230911023038.30649-3-yong.wu@mediatek.com/] +--- + drivers/dma-buf/dma-heap.c | 38 ++++++++++++++++++++++++++++++++++---- + include/linux/dma-heap.h | 6 ++++++ + 2 files changed, 40 insertions(+), 4 deletions(-) + +diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c +index 84ae708fafe7..59328045975a 100644 +--- a/drivers/dma-buf/dma-heap.c ++++ b/drivers/dma-buf/dma-heap.c +@@ -12,6 +12,7 @@ + #include <linux/dma-buf.h> + #include <linux/err.h> + #include <linux/xarray.h> ++#include <linux/kref.h> + #include <linux/list.h> + #include <linux/slab.h> + #include <linux/nospec.h> +@@ -31,6 +32,8 @@ + * @heap_devt heap device node + * @list list head connecting to list of heaps + * @heap_cdev heap char device ++ * @minor: heap device node minor number ++ * @refcount: reference counter for this heap device + * + * Represents a heap of memory from which buffers can be made. + */ +@@ -41,6 +44,8 @@ struct dma_heap { + dev_t heap_devt; + struct list_head list; + struct cdev heap_cdev; ++ int minor; ++ struct kref refcount; + }; + + static LIST_HEAD(heap_list); +@@ -220,7 +225,6 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) + { + struct dma_heap *heap, *h, *err_ret; + struct device *dev_ret; +- unsigned int minor; + int ret; + + if (!exp_info->name || !strcmp(exp_info->name, "")) { +@@ -237,12 +241,13 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) + if (!heap) + return ERR_PTR(-ENOMEM); + ++ kref_init(&heap->refcount); + heap->name = exp_info->name; + heap->ops = exp_info->ops; + heap->priv = exp_info->priv; + + /* Find unused minor number */ +- ret = xa_alloc(&dma_heap_minors, &minor, heap, ++ ret = xa_alloc(&dma_heap_minors, &heap->minor, heap, + XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL); + if (ret < 0) { + pr_err("dma_heap: Unable to get minor number for heap\n"); +@@ -251,7 +256,7 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) + } + + /* Create device */ +- heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), minor); ++ heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor); + + cdev_init(&heap->heap_cdev, &dma_heap_fops); + ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1); +@@ -295,12 +300,37 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) + err2: + cdev_del(&heap->heap_cdev); + err1: +- xa_erase(&dma_heap_minors, minor); ++ xa_erase(&dma_heap_minors, heap->minor); + err0: + kfree(heap); + return err_ret; + } + ++static void dma_heap_release(struct kref *ref) ++{ ++ struct dma_heap *heap = container_of(ref, struct dma_heap, refcount); ++ ++ /* Note, we already holding the heap_list_lock here */ ++ list_del(&heap->list); ++ ++ device_destroy(dma_heap_class, heap->heap_devt); ++ cdev_del(&heap->heap_cdev); ++ xa_erase(&dma_heap_minors, heap->minor); ++ ++ kfree(heap); ++} ++ ++void dma_heap_put(struct dma_heap *h) ++{ ++ /* ++ * Take the heap_list_lock now to avoid racing with code ++ * scanning the list and then taking a kref. ++ */ ++ mutex_lock(&heap_list_lock); ++ kref_put(&h->refcount, dma_heap_release); ++ mutex_unlock(&heap_list_lock); ++} ++ + static char *dma_heap_devnode(const struct device *dev, umode_t *mode) + { + return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev)); +diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h +index 0c05561cad6e..f8c986dd9a8b 100644 +--- a/include/linux/dma-heap.h ++++ b/include/linux/dma-heap.h +@@ -65,4 +65,10 @@ const char *dma_heap_get_name(struct dma_heap *heap); + */ + struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info); + ++/** ++ * dma_heap_put - drops a reference to a dmabuf heap, potentially freeing it ++ * @heap: the heap whose reference count to decrement ++ */ ++void dma_heap_put(struct dma_heap *heap); ++ + #endif /* _DMA_HEAPS_H */ +-- +2.25.1 + |