[PATCH v6 09/24] x86/resctrl: Use set_bit()/clear_bit() instead of open coding

James Morse
2023-09-14T17:22:48Z

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

A subsequent patch adds resctrl_closid_is_free(), which adds more open
coded bitmaps operations. These will eventually need changing to use
the bitops helpers so that a CLOSID bitmap of the correct size can be
allocated dynamically.

Convert the existing open coded bit manipulations of closid_free_map
to use set_bit() and friends.

Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-By: Peter Newman <peternewman@google.com>
Signed-off-by: James Morse <james.morse@arm.com>
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index ac1a6437469f..fa449ee0d1a7 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -106,7 +106,7 @@ 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)
@@ -126,7 +126,7 @@ 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;
+ clear_bit(0, &closid_free_map);
closid_free_map_len = rdt_min_closid;
}

@@ -137,14 +137,14 @@ static int closid_alloc(void)
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;
+ set_bit(closid, &closid_free_map);
}

/**
@@ -156,7 +156,7 @@ void closid_free(int closid)
*/
static bool closid_allocated(unsigned int closid)
{
- return (closid_free_map & (1 << closid)) == 0;
+ return !test_bit(closid, &closid_free_map);
}

/**
--
2.39.2