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After commit18a9ec886d("usb: uhci: Add Aspeed AST2700 support"), clang incorrectly warns: In file included from drivers/usb/host/uhci-hcd.c:855: drivers/usb/host/uhci-platform.c:69:32: error: shift count >= width of type [-Werror,-Wshift-count-overflow] 69 | static const u64 dma_mask_64 = DMA_BIT_MASK(64); | ^~~~~~~~~~~~~~~~ include/linux/dma-mapping.h:93:54: note: expanded from macro 'DMA_BIT_MASK' 93 | #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1)) | ^ ~~~ clang has a long outstanding and complicated problem [1] with generating a proper control flow graph at global scope, resulting in it being unable to understand that this shift can never happen due to the 'n == 64' check. Restructure the code to only use DMA_BIT_MASK() within uhci_hcd_platform_probe() (i.e., function scope) to avoid this global scope issue, similar to the approach of commit274f2232a9("usb: ehci: Add Aspeed AST2700 support"). Closes: https://github.com/ClangBuiltLinux/linux/issues/2136 Link: https://github.com/ClangBuiltLinux/linux/issues/92 [1] Reviewed-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Ryan Chen <ryan_chen@aspeedtech.com> Link: https://patch.msgid.link/20251015-usb-uhci-avoid-bogus-clang-shift-warning-v2-1-68532d2f6114@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.