In preparation for modularizing io-pgtable formats, add support for reference counting the io-pgtable format modules to ensure that the modules are not unloaded while they are in use.
Signed-off-by: Isaac J. Manjarres isaacm@codeaurora.org --- drivers/iommu/io-pgtable-arm-v7s.c | 1 + drivers/iommu/io-pgtable-arm.c | 5 +++++ drivers/iommu/io-pgtable.c | 12 ++++++++++-- include/linux/io-pgtable.h | 2 ++ 4 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c index 89aad2f..a5cb755a 100644 --- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -840,6 +840,7 @@ static struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns = { .fmt = ARM_V7S, .alloc = arm_v7s_alloc_pgtable, .free = arm_v7s_free_pgtable, + .owner = THIS_MODULE, };
#ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S_SELFTEST diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index ff0ea2f..e8b1e34 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -1049,26 +1049,31 @@ static struct io_pgtable_init_fns io_pgtable_arm_lpae_init_fns[] = { .fmt = ARM_32_LPAE_S1, .alloc = arm_32_lpae_alloc_pgtable_s1, .free = arm_lpae_free_pgtable, + .owner = THIS_MODULE, }, { .fmt = ARM_32_LPAE_S2, .alloc = arm_32_lpae_alloc_pgtable_s2, .free = arm_lpae_free_pgtable, + .owner = THIS_MODULE, }, { .fmt = ARM_64_LPAE_S1, .alloc = arm_64_lpae_alloc_pgtable_s1, .free = arm_lpae_free_pgtable, + .owner = THIS_MODULE, }, { .fmt = ARM_64_LPAE_S2, .alloc = arm_64_lpae_alloc_pgtable_s2, .free = arm_lpae_free_pgtable, + .owner = THIS_MODULE, }, { .fmt = ARM_MALI_LPAE, .alloc = arm_mali_lpae_alloc_pgtable, .free = arm_lpae_free_pgtable, + .owner = THIS_MODULE, }, };
diff --git a/drivers/iommu/io-pgtable.c b/drivers/iommu/io-pgtable.c index 2c6eb2e..cc83542 100644 --- a/drivers/iommu/io-pgtable.c +++ b/drivers/iommu/io-pgtable.c @@ -10,6 +10,7 @@ #include <linux/bug.h> #include <linux/io-pgtable.h> #include <linux/kernel.h> +#include <linux/module.h> #include <linux/rwlock.h> #include <linux/slab.h> #include <linux/types.h> @@ -52,9 +53,14 @@ struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt, if (!fns) return NULL;
+ if (!try_module_get(fns->owner)) + return NULL; + iop = fns->alloc(cfg, cookie); - if (!iop) + if (!iop) { + module_put(fns->owner); return NULL; + }
iop->fmt = fmt; iop->cookie = cookie; @@ -79,8 +85,10 @@ void free_io_pgtable_ops(struct io_pgtable_ops *ops) iop = io_pgtable_ops_to_pgtable(ops); io_pgtable_tlb_flush_all(iop); fns = io_pgtable_get_init_fns(iop->fmt); - if (fns) + if (fns) { fns->free(iop); + module_put(fns->owner); + } } EXPORT_SYMBOL_GPL(free_io_pgtable_ops);
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h index 45b367ce..a03b262 100644 --- a/include/linux/io-pgtable.h +++ b/include/linux/io-pgtable.h @@ -169,11 +169,13 @@ struct io_pgtable_ops { * @fmt: The page table format. * @alloc: Allocate a set of page tables described by cfg. * @free: Free the page tables associated with iop. + * @owner: Driver module providing these ops. */ struct io_pgtable_init_fns { enum io_pgtable_fmt fmt; struct io_pgtable *(*alloc)(struct io_pgtable_cfg *cfg, void *cookie); void (*free)(struct io_pgtable *iop); + struct module *owner; };
/**