Commit 5d920b68 authored by James Morse's avatar James Morse Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Use __set_bit()/__clear_bit() instead of open coding 



The resctrl CLOSID allocator uses a single 32bit word to track which
CLOSID are free. The setting and clearing of bits is open coded.

Convert the existing open coded bit manipulations of closid_free_map
to use __set_bit() and friends. These don't need to be atomic as this
list is protected by the mutex.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Reviewed-by: default avatarBabu Moger <babu.moger@amd.com>
Tested-by: default avatarShaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-10-james.morse@arm.com


Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
parent b30a55df

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+12 −6
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ void rdt_staged_configs_clear(void) 
 * - Our choices on how to configure each resource become progressively more

 *   limited as the number of resources grows.

 */

static int closid_free_map;

static unsigned long closid_free_map;

static int closid_free_map_len;



int closids_supported(void)
@@ -130,8 +130,8 @@ static void closid_init(void) 


	closid_free_map = BIT_MASK(rdt_min_closid) - 1;



	/* CLOSID 0 is always reserved for the default group */

	closid_free_map &= ~1;

	/* RESCTRL_RESERVED_CLOSID is always reserved for the default group */

	__clear_bit(RESCTRL_RESERVED_CLOSID, &closid_free_map);

	closid_free_map_len = rdt_min_closid;

}
@@ -139,17 +139,21 @@ static int closid_alloc(void) 
{

	u32 closid = ffs(closid_free_map);



	lockdep_assert_held(&rdtgroup_mutex);



	if (closid == 0)

		return -ENOSPC;

	closid--;

	closid_free_map &= ~(1 << closid);

	__clear_bit(closid, &closid_free_map);



	return closid;

}



void closid_free(int closid)

{

	closid_free_map |= 1 << closid;

	lockdep_assert_held(&rdtgroup_mutex);



	__set_bit(closid, &closid_free_map);

}



/**
@@ -161,7 +165,9 @@ void closid_free(int closid) 
 */

static bool closid_allocated(unsigned int closid)

{

	return (closid_free_map & (1 << closid)) == 0;

	lockdep_assert_held(&rdtgroup_mutex);



	return !test_bit(closid, &closid_free_map);

}



/**