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 --- lib/genalloc.c | 51 +++++++++++++++++++++++++-------------------------- 1 file changed, 25 insertions(+), 26 deletions(-) (limited to 'lib') diff --git a/lib/genalloc.c b/lib/genalloc.c index 7e85d1e37a6e..770c769d7cb7 100644 --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -168,20 +168,21 @@ struct gen_pool *gen_pool_create(int min_alloc_order, int nid) EXPORT_SYMBOL(gen_pool_create); /** - * gen_pool_add_virt - add a new chunk of special memory to the pool + * gen_pool_add_owner- add a new chunk of special memory to the pool * @pool: pool to add new memory chunk to * @virt: virtual starting address of memory chunk to add to pool * @phys: physical starting address of memory chunk to add to pool * @size: size in bytes of the memory chunk to add to pool * @nid: node id of the node the chunk structure and bitmap should be * allocated on, or -1 + * @owner: private data the publisher would like to recall at alloc time * * Add a new chunk of special memory to the specified pool. * * Returns 0 on success or a -ve errno on failure. */ -int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys, - size_t size, int nid) +int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys, + size_t size, int nid, void *owner) { struct gen_pool_chunk *chunk; int nbits = size >> pool->min_alloc_order; @@ -195,6 +196,7 @@ int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phy chunk->phys_addr = phys; chunk->start_addr = virt; chunk->end_addr = virt + size - 1; + chunk->owner = owner; atomic_long_set(&chunk->avail, size); spin_lock(&pool->lock); @@ -203,7 +205,7 @@ int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phy return 0; } -EXPORT_SYMBOL(gen_pool_add_virt); +EXPORT_SYMBOL(gen_pool_add_owner); /** * gen_pool_virt_to_phys - return the physical address of memory @@ -260,35 +262,20 @@ void gen_pool_destroy(struct gen_pool *pool) EXPORT_SYMBOL(gen_pool_destroy); /** - * 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. - */ -unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) -{ - return gen_pool_alloc_algo(pool, size, pool->algo, pool->data); -} -EXPORT_SYMBOL(gen_pool_alloc); - -/** - * gen_pool_alloc_algo - allocate special memory from the pool + * gen_pool_alloc_algo_owner - allocate special memory from the pool * @pool: pool to allocate from * @size: number of bytes to allocate from the pool * @algo: algorithm passed from caller * @data: data passed to algorithm + * @owner: optionally retrieve the chunk owner * * 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. */ -unsigned long gen_pool_alloc_algo(struct gen_pool *pool, size_t size, - 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) { struct gen_pool_chunk *chunk; unsigned long addr = 0; @@ -299,6 +286,9 @@ unsigned long gen_pool_alloc_algo(struct gen_pool *pool, size_t size, BUG_ON(in_nmi()); #endif + if (owner) + *owner = NULL; + if (size == 0) return 0; @@ -326,12 +316,14 @@ retry: addr = chunk->start_addr + ((unsigned long)start_bit << order); size = nbits << order; atomic_long_sub(size, &chunk->avail); + if (owner) + *owner = chunk->owner; break; } rcu_read_unlock(); return addr; } -EXPORT_SYMBOL(gen_pool_alloc_algo); +EXPORT_SYMBOL(gen_pool_alloc_algo_owner); /** * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage @@ -367,12 +359,14 @@ EXPORT_SYMBOL(gen_pool_dma_alloc); * @pool: pool to free to * @addr: starting address of memory to free back to pool * @size: size in bytes of memory to free + * @owner: private data stashed at gen_pool_add() time * * Free previously allocated special memory back to the specified * pool. Can not be used in NMI handler on architectures without * NMI-safe cmpxchg implementation. */ -void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) +void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size, + void **owner) { struct gen_pool_chunk *chunk; int order = pool->min_alloc_order; @@ -382,6 +376,9 @@ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) BUG_ON(in_nmi()); #endif + if (owner) + *owner = NULL; + nbits = (size + (1UL << order) - 1) >> order; rcu_read_lock(); list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { @@ -392,6 +389,8 @@ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) BUG_ON(remain); size = nbits << order; atomic_long_add(size, &chunk->avail); + if (owner) + *owner = chunk->owner; rcu_read_unlock(); return; } @@ -399,7 +398,7 @@ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) rcu_read_unlock(); BUG(); } -EXPORT_SYMBOL(gen_pool_free); +EXPORT_SYMBOL(gen_pool_free_owner); /** * gen_pool_for_each_chunk - call func for every chunk of generic memory pool -- cgit v1.2.3-59-g8ed1b