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usb: usbfs: Use consistent mmap functions 

When hcd->localmem_pool is non-null, localmem_pool is used to allocate
DMA memory. In this case, the dma address will be properly returned (in
dma_handle), and dma_mmap_coherent should be used to map this memory
into the user space. However, the current implementation uses
pfn_remap_range, which is supposed to map normal pages.

Instead of repeating the logic in the memory allocation function, this
patch introduces a more robust solution. Here, the type of allocated
memory is checked by testing whether dma_handle is properly set. If
dma_handle is properly returned, it means some DMA pages are allocated
and dma_mmap_coherent should be used to map them. Otherwise, normal
pages are allocated and pfn_remap_range should be called. This ensures
that the correct mmap functions are used consistently, independently
with logic details that determine which type of memory gets allocated.

Fixes: a0e710a7de ("USB: usbfs: fix mmap dma mismatch")
Cc: stable@vger.kernel.org
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Link: https://lore.kernel.org/r/20230515130958.32471-3-lrh2000@pku.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ruihan Li 2023-05-15 21:09:56 +08:00 committed by Greg Kroah-Hartman
parent 0143d148d1
commit d0b861653f
1 changed files with 9 additions and 2 deletions
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11
drivers/usb/core/devio.c
View File

@ -235,7 +235,7 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
size_t size = vma->vm_end - vma->vm_start;
void *mem;
unsigned long flags;
dma_addr_t dma_handle;
dma_addr_t dma_handle = DMA_MAPPING_ERROR;
int ret;
ret = usbfs_increase_memory_usage(size + sizeof(struct usb_memory));
@ -265,7 +265,14 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
usbm->vma_use_count = 1;
INIT_LIST_HEAD(&usbm->memlist);
if (hcd->localmem_pool || !hcd_uses_dma(hcd)) {
/*
* In DMA-unavailable cases, hcd_buffer_alloc_pages allocates
* normal pages and assigns DMA_MAPPING_ERROR to dma_handle. Check
* whether we are in such cases, and then use remap_pfn_range (or
* dma_mmap_coherent) to map normal (or DMA) pages into the user
* space, respectively.
*/
if (dma_handle == DMA_MAPPING_ERROR) {
if (remap_pfn_range(vma, vma->vm_start,
virt_to_phys(usbm->mem) >> PAGE_SHIFT,
size, vma->vm_page_prot) < 0) {