staging: gasket: page_table: simplify gasket_components_to_dev_address (4a966fa2) · Commits · 戴 / test

Refactor gasket_components_to_dev_address to be faster and easier to understand. The old implementation was unnecessarily complex and masked the page_index for simple addresses but not extended ones. It makes the most sense for this function to perform no such masking. Signed-off-by:

Nick Ewalt <nicholasewalt@google.com> Signed-off-by:

Todd Poynor <toddpoynor@google.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gasket/gasket_page_table.c

+2 −19

Original line number	Diff line number	Diff line
		@@ -699,26 +699,9 @@ static ulong gasket_components_to_dev_address(struct gasket_page_table *pg_tbl,
		int is_simple, uint page_index,
		uint offset)
		{
		ulong lvl0_index, lvl1_index;
		ulong dev_addr = (page_index << GASKET_SIMPLE_PAGE_SHIFT) \| offset;

		if (is_simple) {
		/* Return simple addresses directly. */
		lvl0_index = page_index & (pg_tbl->config.total_entries - 1);
		return (lvl0_index << GASKET_SIMPLE_PAGE_SHIFT) \| offset;
		}

		/*
		* This could be compressed into fewer statements, but
		* A) the compiler should optimize it
		* B) this is not slow
		* C) this is an uncommon operation
		* D) this is actually readable this way.
		*/
		lvl0_index = page_index / GASKET_PAGES_PER_SUBTABLE;
		lvl1_index = page_index & (GASKET_PAGES_PER_SUBTABLE - 1);
		return (pg_tbl)->extended_flag \|
		(lvl0_index << GASKET_EXTENDED_LVL0_SHIFT) \|
		(lvl1_index << GASKET_EXTENDED_LVL1_SHIFT) \| offset;
		return is_simple ? dev_addr : (pg_tbl->extended_flag \| dev_addr);
		}

		/*

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