From 795ee30648c708502da9df637f83c33361d68dcc Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 13 Jun 2019 15:56:27 -0700 Subject: lib/genalloc: introduce chunk owners MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The p2pdma facility enables a provider to publish a pool of dma addresses for a consumer to allocate. A genpool is used internally by p2pdma to collect dma resources, 'chunks', to be handed out to consumers. Whenever a consumer allocates a resource it needs to pin the 'struct dev_pagemap' instance that backs the chunk selected by pci_alloc_p2pmem(). Currently that reference is taken globally on the entire provider device. That sets up a lifetime mismatch whereby the p2pdma core needs to maintain hacks to make sure the percpu_ref is not released twice. This lifetime mismatch also stands in the way of a fix to devm_memremap_pages() whereby devm_memremap_pages_release() must wait for the percpu_ref ->release() callback to complete before it can proceed to teardown pages. So, towards fixing this situation, introduce the ability to store a 'chunk owner' at gen_pool_add() time, and a facility to retrieve the owner at gen_pool_{alloc,free}() time. For p2pdma this will be used to store and recall individual dev_pagemap reference counter instances per-chunk. Link: http://lkml.kernel.org/r/155727338118.292046.13407378933221579644.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reviewed-by: Ira Weiny Reviewed-by: Logan Gunthorpe Cc: Bjorn Helgaas Cc: "Jérôme Glisse" Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/genalloc.h | 55 ++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 49 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h index dd0a452373e7..a337313e064f 100644 --- a/include/linux/genalloc.h +++ b/include/linux/genalloc.h @@ -75,6 +75,7 @@ struct gen_pool_chunk { struct list_head next_chunk; /* next chunk in pool */ atomic_long_t avail; phys_addr_t phys_addr; /* physical starting address of memory chunk */ + void *owner; /* private data to retrieve at alloc time */ unsigned long start_addr; /* start address of memory chunk */ unsigned long end_addr; /* end address of memory chunk (inclusive) */ unsigned long bits[0]; /* bitmap for allocating memory chunk */ @@ -96,8 +97,15 @@ struct genpool_data_fixed { extern struct gen_pool *gen_pool_create(int, int); extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); -extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, - size_t, int); +extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t, + size_t, int, void *); + +static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr, + phys_addr_t phys, size_t size, int nid) +{ + return gen_pool_add_owner(pool, addr, phys, size, nid, NULL); +} + /** * gen_pool_add - add a new chunk of special memory to the pool * @pool: pool to add new memory chunk to @@ -116,12 +124,47 @@ static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, return gen_pool_add_virt(pool, addr, -1, size, nid); } extern void gen_pool_destroy(struct gen_pool *); -extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); -extern unsigned long gen_pool_alloc_algo(struct gen_pool *, size_t, - genpool_algo_t algo, void *data); +unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size, + genpool_algo_t algo, void *data, void **owner); + +static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool, + size_t size, void **owner) +{ + return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data, + owner); +} + +static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool, + size_t size, genpool_algo_t algo, void *data) +{ + return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL); +} + +/** + * gen_pool_alloc - allocate special memory from the pool + * @pool: pool to allocate from + * @size: number of bytes to allocate from the pool + * + * Allocate the requested number of bytes from the specified pool. + * Uses the pool allocation function (with first-fit algorithm by default). + * Can not be used in NMI handler on architectures without + * NMI-safe cmpxchg implementation. + */ +static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) +{ + return gen_pool_alloc_algo(pool, size, pool->algo, pool->data); +} + extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma); -extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); +extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, + size_t size, void **owner); +static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr, + size_t size) +{ + gen_pool_free_owner(pool, addr, size, NULL); +} + extern void gen_pool_for_each_chunk(struct gen_pool *, void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); extern size_t gen_pool_avail(struct gen_pool *); -- cgit v1.2.3-58-ga151