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Subject[PATCH 2/2] x86/intel_rdt: Fix cleanup of plr structure on error
Date
When a resource group enters pseudo-locksetup mode a pseudo_lock_region
is associated with it. When the user writes to the resource group's
schemata file the CBM of the requested pseudo-locked region is entered
into the pseudo_lock_region struct. If any part of pseudo-lock region
creation fails the resource group will remain in pseudo-locksetup mode
with the pseudo_lock_region associated with it.

In case of failure during pseudo-lock region creation care needs to be
taken to ensure that the pseudo_lock_region struct associated with the
resource group is cleared from any pseudo-locking data - especially the
CBM. This is because the existence of a pseudo_lock_region struct with a
CBM is significant in other areas of the code, for example, the display
of bit_usage and initialization of a new resource group.

Fix the error path of pseudo-lock region creation to ensure that the
pseudo_lock_region struct is cleared at each error exit.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c | 22 ++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
index 1860ec10302d..8fd79c281ee6 100644
--- a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
+++ b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
@@ -290,6 +290,7 @@ static void pseudo_lock_region_clear(struct pseudo_lock_region *plr)
static int pseudo_lock_region_init(struct pseudo_lock_region *plr)
{
struct cpu_cacheinfo *ci;
+ int ret;
int i;

/* Pick the first cpu we find that is associated with the cache. */
@@ -298,7 +299,8 @@ static int pseudo_lock_region_init(struct pseudo_lock_region *plr)
if (!cpu_online(plr->cpu)) {
rdt_last_cmd_printf("cpu %u associated with cache not online\n",
plr->cpu);
- return -ENODEV;
+ ret = -ENODEV;
+ goto out_region;
}

ci = get_cpu_cacheinfo(plr->cpu);
@@ -312,8 +314,11 @@ static int pseudo_lock_region_init(struct pseudo_lock_region *plr)
}
}

+ ret = -1;
rdt_last_cmd_puts("unable to determine cache line size\n");
- return -1;
+out_region:
+ pseudo_lock_region_clear(plr);
+ return ret;
}

/**
@@ -365,16 +370,23 @@ static int pseudo_lock_region_alloc(struct pseudo_lock_region *plr)
*/
if (plr->size > KMALLOC_MAX_SIZE) {
rdt_last_cmd_puts("requested region exceeds maximum size\n");
- return -E2BIG;
+ ret = -E2BIG;
+ goto out_region;
}

plr->kmem = kzalloc(plr->size, GFP_KERNEL);
if (!plr->kmem) {
rdt_last_cmd_puts("unable to allocate memory\n");
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out_region;
}

- return 0;
+ ret = 0;
+ goto out;
+out_region:
+ pseudo_lock_region_clear(plr);
+out:
+ return ret;
}

/**
--
2.17.0
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